Human Anatomy Complete Notes

Human Anatomy
Doctor of Pharmacy, PharmD
PharmoHub Pakistan
1st Professional, PharmD

From Cells to Or
ganisms
Dr Ahmad Ali Qureshi
(MBBS,GMC)
PharmoHub Pakistan

1. Define: Cell, Tissue, organ, and organ sys
tem (DK).
2. Describe two types of tissue (DK)
3. Describe two types of organs (DK)
4. Create a flow chart illustrating relationshi
p between cells, tissues, organs, systems an
d organisms (PK)
Lesson Objectives

Levels of Organization
 Cell—Basic unit of structure and function in orga
nisms.
 Some organisms, like bacteria and protists, are
unicellular (made entirely of one cell).
 Some organisms, like fungi, plants, and animal
s, are multicellular (made of many cells).
 In multicellular organisms, cells exhibit cell spe
cialisation. They take on specific jobs and loo
k different from each other.
 The cells also exhibit division of labor. They spli
t up the work of the organism.

 Tissues—Groups of similar cells that work to
gether to perform a specific function.
 4 major tissue types in animals
 Epithelial tissue
 Connective tissue
 Muscle tissue
 Nervous tissue

 Organs—structures made of different types of
tissues that work together to perform a specifi
c function.
 Examples
 Heart
 Lungs
 Stomach
 Small intestine
 Liver
 Large Intestine
 Gall Bladder
 Plant Roots
 Plant Stems
 Plant Leaves

 Organ Systems—Groups of organs that w
ork together to perform a specific functio
n.
 Examples:
 Digestive system
 Circulatory system
 Respiratory system
 Nervous system
 Muscular system
 Skeletal system
 Integumentary system (skin)
 Vascular system in plants

 Organism—A complete, individual living t
hing.
 Examples:
 A single person
 A single plant
 A single bacterium
 A single protist

Write your answers in complete sentences
Q 1: A (tissue, organ, system) is a group of the same kinds of cells that work together.
Choose the right answer.
system
organ
tissue
Q 2: Some tissues and organs work together like the members of the team. The parts
that work together are called a _____________.
cell
system
group
Q 3: The mouth, teeth, tongue, stomach and intestines all work together. Therefore th
ey are called the important parts of __________________.
digestive system
circulatory system
muscular system
Q 4: Brain, heart and lungs are some of the important _______________ in a body.
organs
tissues
cells
system
Q 5: Different tissues work together to form _________ .
cells
system
organs
Q 6: Different systems work together to form organs. True or false?
false
true

11
Organization of Vertebrate Bo
dy
Tissues are groups of cells that are sim
ilar in structure and function
In humans, there are four primary tiss
ues:
-Epithelial, connective, muscle and
nerve

12
Organization of Vertebrate Bo
dy
Organs are combinations of different tissues
that form a structural and functional unit
Organ systems are groups of organs that co
operate to perform the major activities of
the body
-The human body contains 11 principal or
gan systems

Organ Systems
 The five main organ systems that we will b
e focusing on in this unit are:
 The Respiratory System
 The Circulatory System
 The Reproductive System
 The Digestive System
 The Excretory System

14
Organization of Human Body
NO Thank you!

15
Digestive System
NO Thank
you!
The organs or parts of the
body that work together
to break down food into
a smaller, more useable f
orm.

16
Circulatory System
NO Thank
you!
The system that carries ox
ygen and nutrients to all
cells in the body and tak
es wastes away from the
cells; it consists of the he
art, blood vessels and blo
od.

17
Respiratory System
NO
Thank you!
The system involved in th
e inhalation of and diffusi
on of oxygen into the blo
od stream, and the remo
val of carbon dioxide fro
m the body via exhalatio
n

Excretory System
The system resp
onsible for the r
emoval of exce
ss water and w
aste from cell r
eactions in the
body

Reproductive System
The male and female reproductive systems are responsi
ble for the production of sperm and ova (eggs), the fertil
isation of ova by sperm, and the gestation of a fertilised
ova into a foetus (unborn baby)

1
Dr. Ahmad Ali Qureshi
(MBBS,GMC)
PharmoHub Pakistan

Human Anatomy:
Its is defined in various ways :-
“It is the study of structure of human body”

c) Its is defined as an important scientific
discipline which is concerned with the i
nvestigation of biological structure by :
i) Dissection ;
ii) Microdissection ;
iii) Light microscopy ;
iv)Electron microscopy ;
v) Radiology ;

Regional anatomy :
Its deals with anatomy of various structures as they
lie in relationship with one another in different re
gion of the body . It is valuable for surgeons.
.

invisible
Surface anatomy:
It deals with the study and identification
of various structures in the living person
by methods of inspection and palpation
It helps to enhance the knowledge acqui
red through dissection of the cadaver by
either of line of study, Regional or syste
matic. It is helpful both in health and di
sease and is daily used in medical practi
ce.

Radiological Anatomy
It deals with the study of structure of hu
man body with the aid of X-Rays. It helps
to investigate the anatomical facts which
cannot be understood by any other meth
od. It is very useful both in health and di
sease and is in current use in modern m
edical practice.

Embryology
It is the study of various changes in the developing orga
nism from the fertilization of ovum up to the birth of t
he baby.

Cytology
It is the study of the cells by various biological methods.

Histology
It is the study of various tissues by various scientific met
hod (microscopy ; histochemistry etc.).

Applied / Clinical Anatomy
It is the direct application of facts of human anatomy to
medicine and surgery. The students are advised to lay t
he stress on applied aspects while they are studying gr
oss anatomy in dissection hall.

Systemic Anatomy
The description of several systems of organs separately a
nd in logical order comes under the head of systematic
anatomy. The several parts of each system not only sho
w a certain similarity of structure but are also associate
d in specialized functions.

Anatomical
Terminologies
 Anatomic position is a specific
body position in which an indi
vidual stands upright with the
feet parallel and flat on the fl
oor.
 The head is level, and the eye
s look forward toward the obs
erver.
 The arms are at either side of
the body with the palms facin
g forward and the thumbs poi
nting away from the body.

Anatomical Terminology
A plane is an imaginary surface that slices t
he body into specific sections.
The three major anatomic planes of referen
ce are the coronal, transverse, and sagittal
planes.

Sections and
Planes
A coronal plane, also ca
lled a frontal plane, is a
vertical plane that divid
es the body into anterio
r (front) and posterior (
back) parts.

Sections and
Planes
 A transverse plane, also cal
led a cross-sectional plane
or horizontal plane, cuts p
erpendicularly along the lo
ng axis of the body or orga
n separating it into both su
perior (upper) and inferior
(lower) parts.

Sections and
Planes
A sagittal plane or m
edian plane, extends
through the body or
organ vertically and
divides the structure
into right and left hal
ves.

Sections and Planes
A sagittal plane in the body midline is a midsagitta
l plane.
A plane that is parallel to the midsagittal plane, b
ut either to the left or the right of it, is termed a p
arasagittal (or sagittal) plane.
A minor plane, called the oblique plane, passes th
rough the specimen at an angle.

Directional Terms of the Bod
y
Directional terms are precise and brief, and
for most of them there is a correlative term
that means just the opposite.

Relative and Directional Terms of
the Body
 Relative to front (belly side) or back (
back side) of the body :
 Anterior = In front of; towar
d the front surface
 Posterior = In back of; towa
rd the back surface
 Dorsal =At the back side of
the human body
 Ventral = At the belly side o
f the human body

the Body
Relative to the head or t
ail of the body:
 Superior = Toward the head o
r above
 Inferior = Toward feet not he
ad
 Caudal = At the rear or tail en
d
 Cranial = At the head end

the Body
 Relative to the midline or center of th
e body:
 Medial = Toward the midlin
e of the body
 Lateral = Away from the mi
dline of the body
 Deep = On the inside, under
neath another structure
 Superficial = On the outside

the Body
Relative to point of atta
chment of the appenda
ge:
 Proximal = Closest to
point of attachment t
o trunk
 Distal = Furthest fro
m point of attachme
nt to trunk

Body Regions
The human body is partitioned into two ma
in regions, called the axial and appendicular
regions.
 the axial region includes the head, neck, and tr
unk which comprise the main vertical axis of o
ur body
 our limbs, or appendages, attach to the body’s
axis and make up the appendicular region

7-30
Skeletal System
 The axial skeleton is composed of the bones along the ce
ntral axis of the body,
 the skull
 the vertebral column
 the thoracic cage
 The appendicular skeleton consists of the bones of the a
ppendages
 upper and lower limbs
 the bones that hold the limbs to the trunk of the body.

CELL AND ITS
STRUCTURE
(MBBS,GMC)
PharmoHub Pakistan

CELL STRUCTURE
Cell form the basic structural and functional
unit of human body. These are of two types
1:somatic cells
2:sex cells

CELL mEmbRANE
The cell membrane is a biological membrane
that separates the interior of all cells from the
outside environment which protects the cell
from its environment. The cell membrane
consists of a lipid bilayer, including cholesterols
that sit between phospholipids to maintain
their fluidity at various temperatures.

FUNCTIONS OF CELL mEmbRANE
● 1_ it forms cell boundaries and acts as a barrier between
cytoplasm and extracellular fluid environment.
2_ through it substances are exchanged between cell
and its environment.compounds of high molecular weight
are exchanged by special processes known as
endocytosis and exocytosis.
3_ it plays an important role in the maintainance of cell
shape.
4_ in certain cells it acts as a medium for conduction of
electrical impulses.

TRANSPORT ACROSS CELL
mEmbRANE

NUCLEUS
It contains the genetic materials and has a direct
influence on metabolic activities of cytoplasm. It is
surrounded by a membrane called NUCLEAR
ENVELOPE. There are one or more rounded darkly
staining bodies called NUCLEOLI. A semi fluid
material called the nuclear ground substance or
NUCLEAR SAP fills the space within the nucleus.
NUCLEAR ENVELOPE consists of two
closely apposed membranes. At numerous points there
are openings in envelope also known as NUCLEAR
PORES. These serve as channels through which
substances pass into and out of the nucleus.

●CHROmATIN which is the granules and
particles of a basophilic material consists of DNA and
associated basic proteins. DNA exists in the form of
flexible rod like structures called CHROMOSOMES. The
number and characteristics of chromosomes encountered
in an individual is known as karyotype.
NUCLEOLIare rounded dense well defined
bodies not curcumscribed by a membrane. It is composed
of ribonucleic acid RNA and associated proteins.

CYTOPLASm
● Most of the metabolic processes of cell occurr in
cytoplasm. It is often divided in three parts
1: centrosome
2: endoplasm
3: ectoplasm
the term CYTOSOL are used for the component
of cytoplasm which occupies space between
organelles inclusions and elements of cytoplasm.

ORGANELLES
● The term organelle literally means little organs. They carry out various special functions essential to life and metabolism of cell.
1_ mITOCHONDRIA
mitochondrion is bounded by two unit membranes. The inner one is
thrown into folds called CRISTAE. The inner surface of internal
membrane as well as cristae is lined by elemantary particles which are
connected to membrane by means of a slender stalk.
FUNCTIONS OF mITOCHONDRIA
these are the major energy source of the cell. They transform
chemical energy of metabolites present in the cytoplasm into
available energy easily accessible to the cell.

GOLGI APPARATUS
● GOLGI APPARATUS appears as a number of curved
stacks of closely packed membranous cisternae
associated with small vesicles and large vacuoles. These
are completely devoid of ribosomes. Their chief function
is the concentration and packing of secretory products of
the cell.
● RIbOSOmES are small bodies present in all
animal cells except mature RBCs. These are the sites
where amino acids are incorporated into polypeptides
and

LYSOSOmES
●are small roughly spherical bodies limited by a single
membrane. These contain hydrolytic enzymes which are
capable of degrading almost all types of biological
macromolecules. These carry out intracellular digestion.
●
CYTOPLASmIC INCLUSIONS
1: LIPIDS
2:GLYCOGEN
3:PIGMENTS
4:CRYSTALS
5:SECETORY GRANULES

CYTOSKELETON
●consists of a complex network of filaments and
microtubules. It plays an important role in
maintenance of cell shape, stabilization of cell
attachments and cellular movements.
FILAMENTS include thick, thin and intermediate
filaments.
MICROTUBULES are long hollow cylindrical
structures which do not branch. They are formed by
polymerization of a protein called tubulin.
Polymerization occurs at microtubules organizing
centers.

VACUOLE
● A vacuole is a membrane-bound cell organelle.
In animal cells, vacuoles are generally small and
help sequester waste products. In plant
cells, vacuoles help maintain water balance.
Sometimes a single vacuole can take up most of
the interior space of the plant cell.

ENDOPLASmIC RETICULUm
● The endoplasmic reticulum (ER) is a
large organelle made of membranous sheets
and tubules that begin near the nucleus and
extend across the cell. The endoplasmic
reticulum creates, packages, and secretes many
of the products created by a cell. Ribosomes,
which create proteins, line a portion of the
endoplasmic reticulum.

Rough Endoplasmic Reticulum (RER) Smooth Endoplasmic Reticulum
(SER)
It possesses ribosomes attached to its
membrane.
It does not have ribosomes on its
membrane.
Formed of cisternae and a few tubules. Formed of vesicles and tubules.
It participates in the synthesis of
enzymes and proteins.
Synthesises glycogen, lipids and
steroids.
It helps in the formation of lysosomes. Gives rise to
Spherosomes/ Oleosomes
It is internal and connected with the
nuclear envelope.
It is peripheral and may be connected
to plasmalemma.
Ribophorins are present and help
ribosomes attach to ER
Devoid of Ribophorins.
It might develop from the nuclear
envelope
Develops from Rough Endoplasmic
Reticulum.
Provides proteins and lipids for Golgi
apparatus.
Provides vesicles for cis-face of Golgi
apparatus.

 Dr Ahmad Ali Qureshi
 (MBBS,GMC)
PharmoHub Pakistan

 As human body develops from
single to multicellular, cells
specialize.
 Body is interdependent system,
malfunction of one group of cells
is catastrophic.
 Cells specialize into types of
tissues, then interspersed into
organs.

 Epithelium
◦ Coverings
◦ Linings of
surfaces
 Connective
◦ Support
◦ Bone, ligaments,
fat
 Muscle
◦ Movement
 Nervous
◦ Control
◦ Brain, nerves,
spinal cord

 Protection
◦ Skin protects from sunlight & bacteria & physical
damage.
 Absorption
◦ Lining of small intestine, absorbing nutrients into
blood
 Filtration
◦ Lining of Kidney tubules filtering wastes from
blood plasma
 Secretion
◦ Different glands produce perspiration, oil,
digestive enzymes and mucus

 Form continuous sheets (fit like tiles)
 Apical Surface
◦ All epithelial cells have a top surface that borders
an open space – known as a lumen
 Basement Membrane
◦ Underside of all epithelial cells which anchors them
to connective tissue
 Avascularity (a = without)
◦ Lacks blood vessels
◦ Nourished by connective tissue
 Regenerate & repair quickly

 Cell Shape
◦ Squamous – flattened like fish
scales
◦ Cuboidal - cubes
◦ Columnar - columns
 Cell Layers
◦ Simple (one layer)
◦ Stratified (many layers)
 Named for the type of cell at the
apical surface.

 Structure
◦ Single Layer of flattened cells
 Function
◦ Absorption, and filtration
◦ Not effective protection – single layer of cells.
 Location
◦ Walls of capillaries, air sacs in lungs
◦ Form serous membranes in body cavity

 Structure
◦ Single layer of cube shaped cells
 Function
◦ Secretion and transportation in glands, filtration in
kidneys
 Location
◦ Glands and ducts (pancreas & salivary), kidney
tubules, covers ovaries

 Structure
◦ Elongated layer of cells with nuclei at same level
 Function
◦ Absorption, Protection & Secretion
◦ When open to body cavities – called mucous
membranes
 Special Features
◦ Microvilli, bumpy extension of apical surface,
increase surface area and absorption rate.
◦ Goblet cells, single cell glands, produce
protective mucus.
 Location
◦ Linings of entire digestive tract

 Structure
◦ Irregularly shaped cells with nuclei at different
levels – appear stratified, but aren’t.
◦ All cells reach basement membrane
 Function
◦ Absorption and Secretion
◦ Goblet cells produce mucus
◦ Cilia (larger than microvilli) sweep mucus
 Location
◦ Respiratory Linings & Reproductive tract

 Structure
◦ Many layers (usually cubodial/columnar at bottom
and squamous at top)
 Function
◦ Protection
◦ Keratin (protein) is accumulated in older cells near
the surface – waterproofs and toughens skin.
 Location
◦ Skin (keratinized), mouth & throat

Keratin
Stratified
Cubodial (layers
of cubodial only)

 Structure
◦ Many layers
◦ Very specialized – cells at base are cuboidal or
columnar, at surface will vary.
◦ Change between stratified & simple as tissue is
stretched out.
 Function
◦ Allows stretching (change size)
 Location
◦ Urinary bladder, ureters & urethra

 One or more cells that make and secrete a
product.
 Secretion = protein in aqueous solution:
hormones, acids, oils.
 Endocrine glands
◦ No duct, release secretion into blood vessels
◦ Often hormones
◦ Thyroid, adrenal and pituitary glands
 Exocrine glands
◦ Contain ducts, empty onto epithelial surface
◦ Sweat, Oil glands, Salivary glands, Mammary
glands.

Branching
 Simple – single, unbranched duct
 Compound – branched.
Shape: tubular or alveolar
 Tubular – shaped like a tube
 Alveolar – shaped like flasks or sacs
 Tubuloalveolar – has both tubes and sacs in
gland

 The basement membrane is a thin, pliable
sheet-like type of extracellular matrix, that
provides cell and tissue support and acts as a
platform for complex signalling.
 The basement membrane is composed of
collagen type IV, laminins, entactin/nidogen,
and proteoglycans that the epithelial cells
themselves secrete.
 It is a non-cellular structure.

 It serves to bind the epithelium with the
underlying or surrounding connective tissue.
 It serves as a sieve or ultrafilter i.e passes
small molecules and impedes transport of
large molecules.
 It serves as a scaffold during epithelial
regeneration or wound healing.
 Plays an important role in cell growth ,
proliferation and differentiation.

Connective Tissue
Dr AhmAD Ali Qureshi
(mBBs,GmC)
PharmoHub Pakistan

 KinDly reCite DurooD e PAK

Connective Tissue
 Function:
- Binds structures together
- Provides support & protection
- Fills spaces
- Produces blood cells
- Stores fat
 For energy, insulation, organ protection

 Structure:
- Tissue cells are widely separated by
extracellular matrix
- Can be solid, semisolid, or liquid
 Matrix of connective tissue determine its
properties

Fibers of the Matrix
 White fibers – contain collagen which
gives the fibers flexibility and strength
 Yellow fibers – contain elastin more elastic
than collagen but not as strong
 Reticular fibers – thin, highly branched
collagenous fibers that provide support

1. Fibrous Connective Tissue
 Loose (areolar) connective tissue
adipose
 Dense connective tissue
Regular
irregular
 Reticular connective tissue

A. Loose (areolar) Connective Tissue
 Lies between other
tissues or between
organs binding them
 Cells made of
fibroblasts – large,
star-shaped cells
 Contains many white
fibers (strong and
flexible) and yellow
fibers (very elastic)

 Adipose tissue is a
type of loose
connective tissue
- stores fats,
provides insulation
- found beneath
skin, around kidney
& heart, breast

B. Dense Connective Tissue
Regular
 Consists of parallel
bundles of
collagenous fibers
 Found in tendons &
ligaments
 Binds organs together
Irregular
 Bundles run in
different direction
 Found in inner portion
of skin

C. Reticular Connective
 Has reticular cells and
reticular fibers
 Also called lymphatic
tissue
 Found in lymph nodes,
spleen, thymus, and red
bone marrow
 Store and produce white
blood cells
 Part of immune system

2. Cartilage
 The cell
(chondrocytes)
lies in small
chambers called
lacunae
 Matrix is solid yet
flexible
 Lacks direct
blood supply, as
a result, it heals
slowly

3 types
- Hyaline cartilage
- Elastic cartilage
- Fibrocartilage

A. Hyaline Cartilage
 Most common
 Matrix contains fine collagenous fibers
Glassy, white, opaque
 Found in the nose, ends of the long bones
and ribs, rings in the trachea

B. Elastic Cartilage
 Contains elastic and
collagenous fibers
 Found in the outer
ear

C. Fibrocartilage
 Matrix contains strong
collagenous fibers
 Function: absorbs
shocks and reduces
friction between joints
 Found in the pads
between the
vertebrae and knee
joints

 Dr AhmAD Ali Qureshi
 (mBBs,GmC)
PhArmohuB PAkistAn

Definition of Bone...
“Bone is the substance that forms the skeleton of the body. It is
composed chiefly of calcium phosphate and calcium carbonate”
funCtions of Bone…
The human skeleton serves six major functions
 Support
 Movement
 Protection
 Production of blood cells
 Storage of iron
 Endocrine regulation

(1) What are the Bone Regions?
 Axial
 Down the center of body
 Skull, vertebral column, rib cage, center pelvis
 Appendicular
 Off the sides of body
 Upper and lower limbs, shoulder and hip bones

 Axial Skeleton (Head + Neck +Trunk)
SKULL 22 Bones
Ear Ossicle (3+3) 6 Bones
Hyoid 1 Bone
Vertebral coloumn 33 Bones
Ribs (12+12) 24 Bones
Sternum 1 bones
Total = 80 Bones
 Appendicular Skeleton (upper lim+lower limb)
Upper limb (Right 32+ Left 32) 64 Bones
Lower limb (Right 31+ Left 31) 62 Bones
Total = 126 Bones
GrAnD totAl 80+126=206 Bones

DeveloPmentAl ClAssifiCAtion
 memBrAne Bones…
Bone formed directly in connective tissue, i.e. by intramembranous
ossification, rather than by replacing cartilage (compare cartilage bone). Small
areas of membrane become jelly-like and attract calcium salts
Examples = Some face bones, skull bones, and part of the clavicle
are membrane bones.
 CArtilAGenous BoBes…
Intracartilaginous ossification • In intra cartilaginous ossification →
cartilaginous model is formed which is closely resemble the bone to be formed.
•This cartilage is subsequently replaced by (not converted into) bone. eg.
Almost all of the long bones.
 memBrAnoCArtilAGenous Bones…
These bones develop partly in membranes and partly in cartilage.
Example=Occipital,Temporal,sphenoid bones of the skull, mandible, clavicle

(2) What are the types of Bones?
 Long
 Short
 Flat
 Irregular

(3) Long Bones
 Longer than they are wide
 Has a shaft and 2 ends
 Weight bearing bones (like steel beams)
 Provide the greatest structure and support
 Examples:
 All limb bones
 Except…. Kneecap,Wrist and Ankle bones

(4) Short Bones
 Nearly same length,width,thickness but shape irregularly
 Allow for wider range of movement
 Examples:
 Wrist (carpals)
 Ankle (tarsals)

(5) Flat Bones
 Thin, flat and curved
 Protect soft tissue (like plates of armor)
 Examples:
 Sternum
 Shoulder blades
 Ribs
 Skull bones

(6) Irregular Bones
 Complicated, unusual shapes
 Muscles, tendons, ligaments usually attach to these
 Examples:
 Vertebrae
 Hip bones

(8) Bone Structure
 Unique based on location + bone type.
 Compact Bone (Outer Layer):
 Dense
 Smooth and Solid to naked eye
 Spongy Bone (Inner Layer):
 Hole-y (like a honeycomb)
 Made of small needle-like, flat pieces called “trabeculae”
 Open spaces between trabeculae are filled with red or yellow bone marrow

(9) Structure of a Long Bone
 Diaphysis:
 Center, main shaft
 Long part of bone
 Made of very thick compact bone surrounding a central marrow cavity
 Epiphysis:
 Ends of bone
 Wider than diaphysis
 Made of compact bone which surrounds spongy bone.
 Joint surface of each epiphysis is covered with hyaline cartilage

 Epiphyseal Line:
 Remnant of Epiphyseal Plate
 Found in adult bones
 Shows amount of cartilage growth during adolescence
 Membranes:
 Periosteum = Around the outside
 Richly supplied with nerve fibers, lymphatic vessels and blood vessels
 Provides anchoring points for tendons and ligaments
 Endosteum = Around the inside
 Surrounds the spongy bone

(12) Chemical Composition of Bone
 Contains organic & inorganic components
 Organic:
 Cells (osteoblasts, osteocytes, osteoclasts)
 Osteoid
 Made of glycoproteins and collagen fibers
 Secreted by osteoblasts
 “filler matrix” around cells
 Contribute to flexibility and tensile strength
 Inorganic:
 Mineral Salts (calcium phosphates)
 Contribute to hardness of bone (allowing for compression resistance)

to Be Cont….
thAnk you…

PARTS OF BONES
&
BLOOD SUPPLY OF BONES
Dr Ahmad Ali Qureshi (MBBS,GMC)
PharmoHub Pakistan

BLOOD SUPPLY OF THE
LONG BONES

Rule of direction of nutrient foramen
 Nutrient foramen directed against the growing end
“ Towards the Elbow we go; from the knee we flee.”
 Nutrient artery
 Metaphysial arteries
 Epiphyseal arteries
 Periosteal arteries

Venous Drainage
 Venous sinus in centre of
 medullary cavity
 Receives blood from medullary
 sinusoids from end arterial loops
 Diaphyseal vein
 Periosteal veins
 Metaphyseal veins
 Epiphyseal veins

ELEVATIONS
 Lines
 Ridges
 crest

Articular surfaces
Head—a large rounded
elevation
Capitulum --a small rounded
elevation
Trochlea---pully shaped
articular surface
Condyles---a rounded knuckle
like articular area

Non articular surfaces
 Processes
 any prominent projection
 Trochenter
 Large blunt process
 Tuberosities
 Large rounded eminence
 Tubercle
 Small rounded eminence
 Malleolus
 A small rounded process

 Epicondyles
 A projection on or
above condyles
 Spine
 A short pointed
projection
 Styloid process
 A long pointed
projection
 Hamulus
 A hook like projection

 Line
 A slight ridge
 Crest
 A prominent border or
ridge
 Fovea
 A small shallow
depression
 Notch
 Indentation in edge of
bone

Facet ---Small,
smooth and
flat areas of
the bone.
Hollow
depression---
Fossa

Nerve supply of bones
 Periosteum at ends-----nerve supplying overlaying
muscle
 Periosteum of subcutaneous bone-----nerve
supplying overlaying skin
 Enter with nutrient artery-----supply bone tissue
 Periosteum is most sensitive region of bone
 Spongy bone more sensitive as compared to
compact bone

Rule of direction of nutrient foramen
 Growing end of bone
 Nutrient foramen directed against the growing end
 Towards the elbow we go
 Growing ends away from elbow
 From the knee we flee
 Growing ends towards the knee

QUEsTION
 Which artery enter
through the nutient
foramina
 Periosteal
 Diaphysial*
 metaphysial
 Endosteal
 cortical
 SEQ’S
 Briefly explain the
blood supply of
mature long bone?

 Unused bones, such as in a paralyzed limb, atrophy
(decrease in size).
 Bone may be absorbed, which occurs in the
mandible when teeth are extracted.
 Bones hypertrophy (enlarge) when they support
increased weight for a long period.

 Trauma to a bone break it.
 Open fracture
 Close fracture
 Healing of fracture the broken ends must be
brought together, approximating their normal
position. This is called
 reduction of a fracture.
Fracture of bone

Bone healing
 surrounding fibroblasts
(connective tissue cells)
proliferate
 secrete collagen
 forms a collar of callus to hold
the bones together
 Bone remodeling in fracture
area & callus calcifies.
 callus resorbed and replaced
by bone.
 After several months, little
evidence of the fracture
remains, especially in young
people

OsTEOPOROsIs
 aging process
 organic and inorganic components
of bone decrease
 resulting in osteoporosis,
 reduction in the quantity of bone,
 atrophy of skeletal tissue
 bones become brittle, lose their
elasticity, and fracture easily.
 Bone scanning is an imaging
method used to assess normal and
diminished bone mass

 Loss of arterial supply to an epiphysis or other
parts of a bone results in the death of bone
tissue—avascular necrosis.
 In some fractures avascular necrosis may occur.
 A number of clinical disorders of epiphyses in
children result from avascular necrosis of unknown
etiology (cause). These disorders are referred to as
osteochondroses.
Avascular Necrosis

 many of breaks in bones are greenstick fractures
 (incomplete breaks caused by bending of the bones).
 Fractures in growing bones heal faster than those in
adult bones.
Greenstick fractures

 Rickets is a softening of bones in children
 due to deficiency or impaired metabolism of vitamin D ,
phosphorus or calcium
 potentially leading to fractures and deformity.
 Osteomalacia is a similar condition
occurring in adults, generally due to a deficiency
of vitamin D.

(mBBs,GmC)
PharmoHub Pakistan

The skeleton
 The study of bones is termed
osteology.
 The adult is composed of
approximately 206 bones. Each
bone is an organ of the skeletal
system. Start at 270 at birth,
decreases with fusion.
 For the convenience of study, the
skeleton is divided into axial and
appendicular parts.

The axial skeleton
The axial skeleton
consists of 80 bones that
form the axis of the body
and which supports and
protects the organs of the
head, neck, and trunk.
 Skull
 Auditory ossicles
 Hyoid bone
 Vertebral column
 Thoracic cage

The appendicular
skeleton
The appendicular skeleton is composed of
126 bones of the upper and lower limbs and
the bony girdles, which anchor the
appendages to the axial skeleton.
 The shoulder girdle (the scapula
and clavicle)
 The upper limb (the humerus,
ulna, radius and bones of the
hand)
 The pelvic girdle (the hip bone)
 The lower limb (the femur, tibia,
fibula and bones of the foot)

Functions of the skeleton
Biological functions
Mechanical functions

Biological functions of the skeleton
a) Haemopoiesis
b)Mineral storage.

Mechanical functions of the skeleton
a) Support
b) Protection
c) Body movement

Classification of bones
Tubular bones
a) Long tubular bones
 humerus,
 radius, ulna,
 femur,
 tibia, fibula
b) Short tubular bones
 metacarpal,
 metatarsal bones and phalanges

Spongy bones
a) Long spongy bones
 sternum,
 ribs, etc
b) Short spongy bones
 carpal and tarsal bones
c) Sesamoid bones
 knee-cap
 pisiform bone, etc.

Flat bones
Skull bones
 Bones of the vault of the
skull
Girdle bones
 The scapula
 The hip bone, etc.

Mixed bones
The vertebrae are mixed, or
irregular bones (their
bodies are referred to
spongy bones, but their
arches and processes are
referred to flat bones).

The Skull
 The skull proTeCTs
 The brain
 Entrances to respiratory system
 Entrance to digestive system
 The skull ConTAins 22 Bones
 8 cranial bones:
 Form the braincase or cranium
 14 facial bones:
 Protect and support entrances to digestive and respiratory tracts

 There Are eiGhT CrAniAl Bones, eACh wiTh A
uniQue shApe:
 Frontal bone (1). This is the flat bone that makes up
your forehead. ...
 Parietal bones (2). This a pair of flat bones located on
either side of your head, behind the frontal bone.
 Temporal bones(2) ...
 Occipital bone(1) ...
 Sphenoid bone(1) ...
 Ethmoid bone(1).

 The mAjor suTures of The skull inCluDe The
followinG:
 Metopic suture. This extends from the top of the head
down the middle of the forehead, toward the nose. ...
 Coronal suture. This extends from ear to ear. ...
 Sagittal suture. ...
 Lambdoid suture.

CrAniAl fossA
 3 basins that comprise the cranial floor or base
 anterior fossa holds the frontal lobe of the brain
 middle fossa holds the temporal lobes of the brain
 posterior fossa contains the cerebellum
 Swelling of the brain may force tissue through foramen
magnum resulting in death
8-19

A fonTAnelle (or fontanel) (colloquially, soft spot) is an
anatomical feature of the infant human skull comprising
any of the soft membranous gaps (sutures) between the
cranial bones that make up the calvaria of a fetus or an
infant.
The fonTAnelle allows the skull to deform during birth
to ease its passage through the birth canal and for expansion
of the brain after birth. The anterior fontanelle typically
closes between the ages of 12 and 18 months.

rAmus, AnGle AnD BoDy of
mAnDiBle
8-24

 At the end of lectures student should able to
 Define arthrology
 Define joints
 Know the various types (classification) of
joints.
 Classify the fixed joints
 Classify slightly moveable joints
 Classify highly moveable joints

 The study of joints is known as arthrology

 JOINT/ ARTHROSES
 A joint is the location at which two or more
Bones/ cartilage make contact.
 They are constructed to allow movement
and provide mechanical support

 Mobility of joints depends on following
factors..
 The shape of articulating surfaces
 Arrangement of various structure which unite
them
 Stucture of joint is index of its functional
activity.i.e; movement

 Synarthroses or immovable/
Solid joint/ non cavitated joint
 Amphiarthroses or slightly
movable
 Diarthroses or freely movable/
Cavitated joint

 The surfaces of the bones are in almost
direct contact
 Fastened together by intervening
connective tissue or hyaline cartilage
 and in which there is no appreciable
motion, as in the joints between the bones
of the skull

Solid joints
(Synarthrosis)
Fibrous Cartilaginous Mixed solid

• Suture
• Gomphosis
• syndesmosis
Fibrous
• Synchondrosis/ Primary
cartilaginous
• Symphsis/Secondary
cartilaginous
Cartilaginous

 Plane
 Squamous
 Serrate

 Limbous
 Both serrated
+ squamous
 Denticulate
 Schindylesis

 An immovable junction between two bones,
such as those of the skull. E.g…
 In a SERRATE SUTURE, the edges are saw like
e.g Sagittal suture.
 A DENTICULATE SUTURE has small tooth like
processes e.g Lambdoid suture.
 In a SQUAMOUS SUTURE reciprocally bevelled
bone margins overlap each other e.g
Temporoparietal suture.
 In a PLANE SUTURE there is simple apposition
of relatively flat bones e.g intermaxillary
suture.

A gomphosis is a fibrous mobile peg-and-
socket joint. The roots of the teeth (the
pegs) fit into their sockets in the mandible
and maxilla and are the only examples of this
type of joint.

 The syndesmosis is a fibrous joint held together
by ligaments. It's located near the ankle joint,
between the tibia, or shinbone, and the distal
fibula, or outside leg bone. That's why it's also
called the distal tibiofibular syndesmosis. It's
actually made up of several ligament

TEMPORARY/ Primary (synchondroses)
 They show intra cartilagenous method of
ossification. They remain in Hyaline cartilage
till completion of growth of bone.
 Strong & immobile
 Sternales
 Epipysial plate
 1st sternocostalis

 Intra articular fibrocartilagenous disc
 Slight movement due to deformation of disc
 In median plane of body
 Intermediate stage of
evolution
 FIBROCARTILAGE WITH CAVITIES
 WITHOUT CAVITY

 Define suture? Classify various types of
sutures with one example .
 Classify non- cavitated joints

 Define sutures
 Give example of serrate suture
 What do you mean by syndesmosis?
 How we differentiate between primary &
secondary cartilaginous joints

 Diarthrosis. A freely mobile joint is classified
as a diarthrosis. These types
of joints include all synovial joints of the
body, which provide the majority of body
movements. Most diarthrotic joints are found
in the appendicular skeleton and thus give
the limbs a wide range of motion.
 Lets have a look on Articular cartilage,
Fibrous Capsule, Ligaments, Synovial
membrane, Synovial fluid,Articular discs.

 ArtiCulAr CArtilAGe : the bones of a synovial joint are
covered by this layer of Hyaline cartilage that lines the epiphyses
of joint end of bone with a smooth, slippery surface that does not
bind them together; articular cartilage functions to absorb shock
and reduce friction during movement.
 FiBrous CApsule : the fibrous capsule, continuous with the
periosteum of articulating bones, surrounds the diarthrosis and
unites the articulating bones; the joint capsule consists of two
layers - (1) the oute rfibrous membrane that may contain
ligaments and (2) the inner synovial membrane that secretes the
lubricating, shock absorbing, and joint-nourishing synovial fluid;
the joint capsule is highly innervated, but without blood and
lymph vessels, and receives nutrition from the surrounding blood
supply via either diffusion (a slow process) or by convection, a far
more efficient process achieved through exercise.
 liGAments : Ligaments are a type of connective tissue and are
tough, fibrous and slightly elastic. They connect bone to bone and
help keep the joint together. They stabilise the joints during
movement and prevent dislocation by restricting actions outside
the normal joint range.

 A synoviAl memBrAne (or synovium) is the soft tissue found
between the articular capsule (joint capsule) and the joint cavity
of synovial joints.
 synoviAl FluiD is the clear, viscid, lubricating fluid secreted
by synovial membranes. The morphology of synovial
membranes may vary, but it often consists of two layers. Volume
of synovial fluid is 0.5 ml in knees.
 Egg albumin like fluid present in joint cavities, bursa and tendon
sheath
 PH- alkaline, turns to acidic
 0.5ml volume
 Hyluronic acid
 Proteins
 Cells – macrophages, lymphocytes, neutrophils, synovial cell
 ArtiCulAr DisC - the fibrocartilage pads between opposing
surfaces in a joint

 Gliding
 Angular
 Rotatory
 Circumductory

Gliding
(a) Gliding movements at the wrist

(b) Angular movements: flexion, extension, and
hyperextension of the neck
Hyperextension Extension
Flexion

Abduction
Adduction
(e) Angular movements: abduction, adduction, and
circumduction of the upper limb at the shoulder
Circumduction

Osteoarthritis Rheumatoid arthritis
Nature of disease Degenerative disease
& inflammatory
Autoimmune &
inflammatory
Tissue effected Articular cartilage Synovial membrane
Joints effected Larger weight bearing
joint
Smaller joints of hand
& feet

CLASSIFICATION OF
SYNOVIAL JOINTS
(MBBS,GMC)
PharmoHub Pakistan

RECAP
 Articular cartilage
 Joint capsule
 Synovial cavity
 Synovial membrane
 Synovial fluid
 Ligaments
 Articular disc

OBJECTIVES
 At the end of lecture you should able to;
 Classify various types of synovial joints.
 Identify the synovial joints according to
the structures.
 Classify joints according to their
articulating surfaces.
 Classify joints according to complexity of
organization

ARCHITECTURAL
OR
STRUCTURAL
CLASSIFICATION
OR
GENERAL CLASSIFICATION

I. PLANE JOINT/ ANTHROIDAL
JOINT
• Bone surfaces are slightly curved/ almost flat.
• Side to side movement/ gliding only
• Rotation prevented by
ligaments
• Examples:
- Intercarpal
- intertarsal joints
- sternoclavicular joint

HINGE JOINT/ GINGLYMOID
• Convex surface of bone fits in concave surface of
2nd bone
• like a door hinge
• Examples:
- Knee, elbow,
- interphalangeal
 Uniaxial
• Movements produced:
- flexion
- Extension
- To and fro

PIVOT / ROTATORY/ TROCHOID
JOINT
• Rounded surface of bone articulates with the ring
formed by the 2nd bone & ligament
 Monoaxial
• since it only allows rotation around longitudinal axis
• Examples:
 Pivot rotates inside
stationary osseofibrous ring
 proximal radioulnar
 Ring rotates around stationary
pivot
 atlanto-axial joint

CONDYLAR/CONDYLOID
• Convex articular surface fits into oval
depression
 Biaxial
• Examples: metacarpophelangeal
joints for 2 to 5 digits

BICONDYLAR JOINT
 Two convex surfaces articulate with two
concave surfaces
Uniaxial
 Two subtypes
 Both condyles present on single capsule
◦ Knee joint
 Both condyles lie at a distance and each
having a separate capsule
◦ Temporomandibular joint

SADDLE/ SELLER/ RECEPTIVE
• One bone saddle-shaped, other bone fits like a
person riding on the saddle
 Biaxial
• Examples:
- Trapezium of carpus and metacarple of
thumb

BALL & SOCKET/ SPHEROIDAL
• Ball fitting into a cup-like depression
• Multiaxial
- flexion/extension
- abduction/adduction
- rotation
• Examples:
- shoulder joint
- hip joint

ELLIPSOID
 Oval convax surface fix into elliptical
concavity
Biaxial
 Example
 Wrist joint

ACCORDING TO DEGREE OF
FREEDOM OF
MOVEMENT(AXIS OF
MOVEMENT)

DEPENDING UPON TYPE OF MOVEMENT/ AXIS
OF MOVEMENT/ DEGREE OF FREEDOM OF
MOVEMENT
 Uniaxial
 Biaxial
 Polyaxial

Uniaxial joint
• Hinge
• Pivot
• Biconylar
Biaxial joint
• Ellipsoid
• Saddle
• Condylar
Multiaxial
joint
• Shoulder
• Hip

DEPENDING UPON COMPLEXITY
OF ORGANIzATION
 SIMPLE :When two bones participating
 COMPOUND : More than two bones
 COMPLEX : Intra articular disc or menisci
present

Simple joint
• When two articulating
surfaces are plane
• Plane joint
• Saddle joint
Homomorphic
• When varied appearance
of articulating surface
• Ball &socket
• Condyloid joint
• Ellipsoid joint
Hetromorphic

NERVE SUPPLY OF JOINTS
(HILTON’S LAw)
 Hilton’s Law; joints are innervated with
the nerve of supply to the muscles, which
act on them
 Motor nerve to the muscle acting on
joints tend to give branch to
 Capsule of that joint
 Skin covering that joint

The
Muscular
sysTeM
Dr ahMaD ali
Qureshi
(MBBs,GMc)
PharmoHub Pakistan

The Muscular System
Slide 6.1
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
 Muscles are responsible for all types of
body movement – they contract or
shorten and are the machine of the
body
 Three basic muscle types are found in
the body
Skeletal muscle
Cardiac muscle
Smooth muscle

Characteristics of Muscles
Slide 6.2
 Muscle cells are elongated
(muscle cell = muscle fiber)
 Contraction of muscles is due to the
movement of microfilaments
 Muscles are derived from MESODERM.
 Prefix myo/mys refers to muscle.

Skeletal Muscle Characteristics
Slide 6.3
 Most are attached by tendons to bones
 Cells are multinucleate
 Striated – have visible banding
 Voluntary – subject to conscious control
 Cells are surrounded and bundled by
connective tissue = great force, but tires
easily

Connective Tissue Wrappings of
Skeletal Muscle
Slide 6.4a
 Endomysium –
around single
muscle fiber
 Perimysium –
around a
fascicle
(bundle) of
fibers Figure 6.1

Connective Tissue Wrappings of
Skeletal Muscle
Slide 6.4b
 Epimysium –
covers the
entire skeletal
muscle
 Fascia – on the
outside of the
epimysium
Figure 6.1

Skeletal Muscle Attachments
Slide 6.5
 Epimysium blends into a connective
tissue attachment
Tendon – cord-like structure
Aponeuroses – sheet-like structure
 Sites of muscle attachment
Bones
Cartilages
Connective tissue coverings

Smooth Muscle Characteristics
Slide 6.6
 Has no striations
 Spindle-shaped cells
 Single nucleus
 Involuntary – no
conscious control
 Found mainly in the
walls of hollow
organs
 Slow, sustained and
tireless
Figure 6.2a

Cardiac Muscle Characteristics
Slide 6.7
 Has striations
 Usually has a single
nucleus
 Joined to another
muscle cell at an
intercalated disc
 Involuntary
 Found only in the
heart
 Steady pace!
Figure 6.2b

Function of Muscles
Slide 6.8
 Produce movement
 Maintain posture
 Stabilize joints
 Generate heat

Microscopic Anatomy of Skeletal
Muscle
Slide 6.9a
 Cells are multinucleate
 Nuclei are just beneath the sarcolemma
Figure 6.3a

Muscle
Slide 6.9b
 Sarcolemma – specialized plasma
membrane
 Sarcoplasmic reticulum – specialized
smooth endoplasmic reticulum
Figure 6.3a

Muscle
Slide
6.10a
 Myofibril
Bundles of myofilaments
Myofibrils are aligned to give distrinct bands
I band =
light band
A band =
dark band
Figure 6.3b

Muscle
Slide
6.10b
 Sarcomere
Contractile unit of a muscle fiber
Figure 6.3b

Muscle
Slide
6.11a
 Organization of the sarcomere
Thick filaments = myosin filaments
Composed of the protein myosin
Has ATPase enzymes
Figure 6.3c

Muscle
Slide
6.11b
 Organization of the sarcomere
Thin filaments = actin filaments
Composed of the protein actin
Figure 6.3c

Muscle
Slide
6.12a
 Myosin filaments have heads
(extensions, or cross bridges)
 Myosin and
actin overlap
somewhat
Figure 6.3d

Properties of Skeletal Muscle
Activity (single cells or fibers)
Slide 6.13
 Irritability – ability to receive and
respond to a stimulus
 Contractility – ability to shorten when an
adequate stimulus is received

Nerve Stimulus to Muscles
Slide 6.14
 Skeletal
muscles must
be stimulated
by a nerve to
contract (motor
neruron)
 Motor unit
One neuron
Muscle cells
stimulated by
that neuron Figure 6.4a

Slide
6.15a
 Neuromuscular
junctions –
association site
of nerve and
muscle
Figure 6.5b

Slide
6.15b
 Synaptic cleft –
gap between
nerve and
muscle
Nerve and
muscle do not
make contact
Area between
nerve and muscle
is filled with
interstitial fluid Figure 6.5b

Transmission of Nerve Impulse to
Muscle
Slide
6.16a
 Neurotransmitter – chemical released by nerve
upon arrival of nerve impulse
 The neurotransmitter for skeletal muscle is
acetylcholine. Others include
Epinephrine,norepinephrine,dopamine,serot
onin.
 Neurotransmitter attaches to receptors on the
sarcolemma
 Sarcolemma becomes permeable to sodium
(Na+)

Transmission of Nerve Impulse to
Muscle
Slide
6.16b
 Sodium rushing into the cell generates
an action potential
 Once started, muscle contraction
cannot be stopped

The Sliding Filament Theory of
Muscle Contraction
Slide
6.17a
 Activation by nerve
causes myosin
heads
(crossbridges) to
attach to binding
sites on the thin
filament
 Myosin heads then
bind to the next site
of the thin filament
Figure 6.7

The Sliding Filament Theory of
Muscle Contraction
Slide
6.17b
 This continued
action causes a
sliding of the myosin
along the actin
 The result is that the
muscle is shortened
(contracted)
Figure 6.7

The Sliding Filament Theory
Slide 6.18
Figure 6.8

Contraction of a Skeletal Muscle
Slide 6.19
 Muscle fiber contraction is “all or none”
 Within a skeletal muscle, not all fibers
may be stimulated during the same
interval
 Different combinations of muscle fiber
contractions may give differing
responses
 Graded responses – different degrees
of skeletal muscle shortening, rapid
stimulus = constant contraction or
tetanus

Energy for Muscle Contraction
Slide 6.23
 Initially, muscles used stored ATP for
energy
Bonds of ATP are broken to release energy
Only 4-6 seconds worth of ATP is stored by
muscles
 After this initial time, other pathways
must be utilized to produce ATP

Slide 6.24
 Direct phosphorylation
 Muscle cells contain creatine
phosphate (CP)
 CP is a high-energy
molecule
 After ATP is depleted, ADP is
left
 CP transfers energy to ADP,
to regenerate ATP
 CP supplies are exhausted in
about 20 seconds
Figure 6.10a

Slide
6.26a
 Anaerobic glycolysis
Reaction that breaks
down glucose without
oxygen
Glucose is broken down
to pyruvic acid to
produce some ATP
Pyruvic acid is
converted to lactic acid
Figure 6.10b

Slide
6.26b
 Anaerobic glycolysis
(continued)
This reaction is not as
efficient, but is fast
Huge amounts of
glucose are needed
Lactic acid produces
muscle fatigue
Figure 6.10b

Slide 6.25
 Aerobic Respiration
Series of metabolic
pathways that occur in
the mitochondria
Glucose is broken down
to carbon dioxide and
water, releasing energy
This is a slower reaction
that requires continuous
oxygen
Figure 6.10c

Muscle Fatigue and Oxygen Debt
Slide 6.27
 When a muscle is fatigued, it is unable to
contract
 The common reason for muscle fatigue is
oxygen debt
Oxygen must be “repaid” to tissue to remove
oxygen debt
Oxygen is required to get rid of accumulated
lactic acid
 Increasing acidity (from lactic acid) and lack
of ATP causes the muscle to contract less

Types of Muscle Contractions
Slide 6.28
 Isotonic contractions
Myofilaments are able to slide past each
other during contractions
The muscle shortens
 Isometric contractions
Tension in the muscles increases
The muscle is unable to shorten

Muscle cONTracTiON
TONIC (normal muscle tone)
PHASIC (It is of 2 types i.e ISOTONIC and
ISOMETRIC )
 Isotonic (Length changes , tension same)
 Isometric ( Length same , tension changes )
Isotonic is further of two types i.e CONCENTRIC
and ECCENTRIC.
REFLEXIVE (spontaneous movement due to O2 or
CO2 concentrations e.g knee reflex)

 cONceNTric MOveMeNT…
 Movement occurs by
shortening of muscles.
 Eg biceps brachi.
 ecceNTric MOveMeNT…
 Movement occurs by
contraction of muscles.
 Eg Lowering a weight
during a shoulder press.
 The downward motion of
squatting.
 The downward motion of a
push-up.
 Lowering the body during a
crunch.
 Lowering the body during a
pull-up.

Muscles and Body Movements
Slide
6.30a
 Movement is
attained due to
a muscle
moving an
attached bone
Figure 6.12

Muscles and Body Movements
Slide
6.30b
 Muscles are
attached to at
least two points
Origin –
attachment to a
moveable bone
Insertion –
attachment to an
immovable bone
Figure 6.12

Effects of Exercise on Muscle
Slide 6.31
 Results of increased muscle use
Increase in muscle size
Increase in muscle strength
Increase in muscle efficiency
Muscle becomes more fatigue resistant

Types of Ordinary Body
Movements
Slide 6.32
 Flexion – decreases angle of joint and
brings two bones closer together
 Extension- opposite of flexion
 Rotation- movement of a bone in
longitudinal axis, shaking head “no”
 Abduction/Adduction (see slides)
 Circumduction (see slides)

Body Movements
Slide 6.33
Figure 6.13

Left:
Abduction –
moving the
leg away
from the
midline
Above –
Adduction-
moving
toward the
midline
Right:
Circumduction: cone-
shaped movement,
proximal end doesn’t
move, while distal end
moves in a circle.

Types of Muscles
Slide 6.35
 Prime mover – muscle with the major
responsibility for a certain movement eg
biceps
 Antagonist – muscle that opposes or
reverses a prime mover eg triceps
 Synergist – muscle that aids a prime
mover in a movement and helps prevent
rotation

D U R I N G F O R E A R M F L EX I O N, F O R E X A MP L E L I F T I NG
A C U P , A MU S C L E C A L L ED T H E B I C E P S B R A C HI I I S
T H E PR I M E MO V E R . B E C A U S E I T C A N B E A S S I S T ED
B Y T H E B R A C H I A L I S , T HE B R A C H I A L I S I S C A L L E D
A S Y N E R G I S T I N T H I S A C T I O N ( F I G U R E 1 1 . 1 . 1 ) .
A S Y N E R G I S T C A N A L S O B E A F I X A T O R T H A T
S T A B I L I Z E S T HE M U S C L E' S O R I G I N .

DisOrDers relaTiNG TO The Muscular
sysTeM
 Muscular Dystrophy: inherited, muscle enlarge due
to increased fat and connective tissue, but fibers
degenerate and atrophy
 Duchenne MD: lacking a protein to maintain the
sarcolemma
 Myasthemia Gravis: progressive weakness due to a
shortage of acetylcholine receptors

(mBBs,GmC)
inteGumentAry system
PharmoHub Pakistan

the sKin
• The integumentary system consists of the skin
(cutaneous membrane) and its accessory organs.
• The skin is composed of three layers of tissue: the
outer epidermis (made of stratified squamous
epithelium ), the middle dermis (made of fibrous
connective tissue ), and the inner subcutaneous layer
or hypodermis (made of adipose tissue and loose
connective tissue).
• Accessory organs include the hair (hair root and hair
shaft) , hair follicle , pili arrector muscle, sebaceous
gland , sudoriferous gland , nails , and mammary
gland.
ebneshahidi

FunCtiOns OF the inteGumentAry
ssystemystem
1. protection
a) chemical factors in the skin:
Sebum (or oil) from the sebaceous glands is slightly
acidic, retarding bacterial colonization on the skin
surface.
Sweat from the sudoriferous glands is slightly
hypertonic and can flush off most bacteria on the skin
surface.
Melanin (skin pigment ) from melonocytes avoids
excessive ultraviolet radiation from penetrating the
skin layers . ebneshahidi

b) physical factors in the skin:
Stratified squamous epithelium in the epidermis
layer provides a large number of layers of cells,
preventing most bacteria invasion.
Keratinized cells in the stratum corneum layer of
the epidermis provides a physical barrier against
most invasion.
c) biological factor in the skin:
White blood cells such as macrophages destroy
most invaded bacteria and other foreign
substances.
ebneshahidi

2. Excretion
waste materials such as ammonia , urea , and excessive
salt are eliminated from sweating .
3. Body temperature regulation
Sweating by the sweat glands promotes evaporation ,
resulting in a loss of excessive body heat.
Vasoconstriction by arterioles (small arteries ) in the
dermis layer provides a smaller surface area in the
blood vessels, resulting in less heat loss .
Vasodilatation by arterioles in the dermis layer
provides a larger surface area in the blood vessels ,
resulting in greater heat loss .
ebneshahidi

4. Cutaneous sensation
Nerve receptors in the dermis layers detect
sensations such as heat, cold, pain, pressure, and
touch, allowing the body to be aware of these
stimuli.
5. Vitamin D synthesis
Ultraviolet radiation in the sunlight activates a
series of chemical reactions in the epidermis
layer, resulting in the synthesis of vitamin D
from the modification of cholesterol for the
absorption of calcium.
ebneshahidi

FunCtiOns OF the sKin
• maintains homeostasis.
• prevents the body from the penetration of harmful
substances.
• Prevents water loss(desiccation) .
• help to regulate body temperature .
• contains nerve receptors for various sensations .
• synthesizes chemical substances such as keratin,
melanin, and vitamin D.
• excretes waste materials such as ammonia , urea , and
salts.
• produces skin pigment (melanin) in the epidermis and
hair to avoid excessive penetration of UV radiation .
ebneshahidi

ePiDermis
• Being made of stratified squamous epithelium , there is no blood
vessels to supply nutrients to its cells.
• Nutrients from the arterioles in the dermis layer diffuse upward
into the epidermis layer, especially to the stratum basale and
spinosum layers.
• Cuboidal cells at the stratum basale (stratum germinativum)
layer receive most of the nourishment . These cells reproduce
rapidly using mitosis . New daughter cells will be pushed upward
into higher layers , and they become flattened as they move
upward .
• Squamous cells moving upward in the epidermis receive less and
less nutrients as diffusion distance increases. By the time they
form stratum corneum , the cells are dead and will be shed off
from the skin .
ebneshahidi

• Epidermal cells in stratum granulosum and stratum corneum
undergo “keratinization " to produce a protein called keratin,
allowing these cells to be tough and waterproof. These cells are
now called " karatinocytes " where they develop desmosomes
between the cells and allow the epidermis to become a stronger
physical barrier .
• F i v e layer of cells are found in the epidermis of the body
stratum basale , stratum spinosum , stratum granulosum , and
stratum corneum. In the palms and soles , an extra layer beneath
stratum coruneum is formed , called stratum Lucidum.
• Specialized cells called melanocytes in the stratum basale layer
produce the skin pigment, melanin. The number of melanocytes
and the amount of melanin production are genetically inherited .
ebneshahidi

lAyers OF ePiDermis
 The 5 Layers of Your Skin
 Stratum Basale or Basal Layer.The deepest layer of the
epidermis is called the stratum basale, sometimes called the
stratum germinativum. ...
 Stratum Spinosum or the Spiny layer.This layer gives
the epidermis its strength. ...
 Stratum Granulosum or the Granular Layer. ...
 Stratum Lucidum. ...
 Stratum Corneum.
NEMONIC : (CLG-SB)

Dermis
• made of fibrous connective tissue that contains
arterioles for supplying nutrients (i.e. oxygen ,
glucose , water , and ions ) to its structures and to the
epidermis .
• also contains pilo-errector muscles (made of skeletal
muscle, under involuntary control) to wrinkle the skin
and erect the hairs .
• contains nerves and nerve receptors to detect the
sensations of heat, cold, pressure, touch, and pain .
• also contains hair follicles to develop the hair .
• contains sebaceous gland to secrete sebum onto skin
surface, and sudoriferous glands to secrete sweat.
ebneshahidi

hyPODermis
– Made of adipose tissue and loose connective
tissue.
– Collagen and elastic fibers in the loose connective
tissue are continuous with the fibers in the dermis
layer.
– Adipose tissue serves as a heat insulator against
cold climate and as a fat storage.
– Loose connective tissue allows the skin to be
bound with underlying muscles.
– Also contains large blood vessels (arteries and
veins).
ebneshahidi

Cells in sKin
KerAtinOCytes
melAnOCytes
merKel Cells
lAnGerhAns Cells

ACCessOry struCtures OF the sKin
1. Hair
– produced by epithelial cells at the hair papilla .
– made of keratinized cells .
– consists two regions: hair root (in the hair follicle
, embedded in the dermis layer), and hair shaft
(protruded through the epidermis to the outside).
– Hair pigment (melanin) is produced by
melonocyets in hair papilla .
– Hair growth is affected by nutrition and hormones
(i.e. testosterone).
ebneshahidi

2. Pili erreCtOr musCle
• made of skeletal muscle ,
but under involuntary
control.
• attached to each hair
follicle, for erecting the
hair.
• situations such as extreme
emotions or extreme
temperatures can activate
its involuntary contraction
, resulting in hair erection
or skin wrinkling.
ebneshahidi

3. seBACeOus GlAnD
• Oil gland that is made of
modified cuboidal epithelium.
• Occurs all over the body
except in the palm and sole.
• Attached to each hair follicle,
so that sebum can be secreted
into the hair root and diffuse
upward .
• Sebum helps the skin and hair
to be waterproof, and retards
bacterial growth on skin
surface(due to its acidity).
ebneshahidi

4. suDOriFerOus GlAnD
• sweat gland that secretes
sweat to promote
evaporation.
• found all over the body
except the lips, nipples,
and external genitalia.
• referred to as "tubular
gland" where it is a long
tubule coiled in the
dermis layer , and uses a
long duct to release
sweat onto skin surface
through a pore.
ebneshahidi

5. nAils
• scale like
modification of
epithelial cells in the
epidermis.
• made of keratin.
• Protect ends of fingers
and toes and prevent
over sensitization of
the never receptors in
extremities.
• Growing cells are
derived form a region
at base of nail called
"lunula".
ebneshahidi

Burns
• First degree burns: only the epidermis is
damaged with redness and swelling .
• Second degree burns: epidermis & upper
region of dermis is involved. There is Redness,
swelling, and blisters.
• Third degree burns: all layers of skin burned
(most severe). Skin graft is necessary to repair.
Skin looks cherry red or blacken
ebneshahidi

sKin CAnCer
• Most skin tumors are benign
• Cause of cancer is unknown, but probably due to
overexposure to ultraviolet radiation in the sunlight .
• Three main types of skin cancer :
• Basal cell carcinoma
• The most common type of skin tumor; usually benign.
• Cells of stratum basale are affected , as a result they
cannot form keratin and begin to invade into the
dermis.
• Surgical removal (given that early detection is done)
is 99% successful .
ebneshahidi

sQuAmOus Cell CArCinOmA
• arises form keratinocytes in stratum spinosum .
• mostly in the scalp , ears , or hands.
• grows and migrates rapidly.
• early detection is critical for successful treatment.
Malignant Melanoma – most dangerous
• cancer of the melanocyets in stratum basale.
• only 5% of all skin cancer , but the frequency is increasing.
• grow and migrates extremely rapidly .
• usually deadly.
Note: To avoid these skin tumors , it is advised that we should stay
away from the sun during its most intense period: from 10 am to 2
pm . ebneshahidi

CliniCAl terms
• Albinism – inherited, melanocytes do not produce melanin.
• Boils and carbuncles – inflammation of hair follicles and
sebaceous glands, infection spread to dermis .
• Contact dermatitis – itching and redness and swelling forming
blisters. It is caused by chemical burns.
• Psoriasis : characterized by reddened epidermal lesions
covered by dry silvery scales.
• Roscea : redness of skin around eyes and nose accompanied by
rash – like lesions, It gets worse with alcohol , hot H2O, and
spicy food .
• Vitiligo : skin pigmentation disorder caused by loss of melan-
octyts and uneven dispersal of melanin (unpigmented skin
surrounded by normally pigmented areas) .
ebneshahidi

AnAtomy of DIGEStIVE
SyStEm
Dr AhmAD AlI QurEShI
mBBS (GmC)
PharmoHub Pakistan

OUTLINE
 Introduction to the Digestive System
 Divisions
 Alimentary Canal
 Accessory Organs
 Organs
 Location
 Functions
THE ROLE OF COMPUTERS IN MEDICAL PHYSICS. VICTOR EKPO. CMUL - LAGOS

INTRODUCTION
The Digestive System is a group of
organs working together to
convert food into energy and
basic nutrients to feed/nourish the
body.
ANATOMY OF THE DIGESTIVE SYSTEM. VICTOR EKPO. CMUL - LAGOS

Fig: Anterior view of the Digestive System

DIVISIONS
The Digestive System consists of 2 parts: the
Alimentary Canal, and their Accessory Organs.
The alimentary canal is also called the digestive tract
OR gastrointestinal tract GIT (though GIT is
technically stomach + intestines only).
The alimentary canal is the long tube that runs from
the mouth through to the anus.

ALIMENTARY CANAL
The main parts of the Alimentary Canal are:
* Mouth (Oral cavity)
* Pharynx (Throat) * Oesophagus (also esophagus)
* Stomach * Small intestine
* Large intestine * Rectum and anal canal (anus).

ACCESSory orGAnS
The Accessory Organs include other organs (mainly glands) that aid
digestion. These include:
Tongue, salivary glands and tonsils (for mouth)
Tubular mucous glands (for pharynx, oesophagus, large intestine)
 Liver, Gallbladder, and Pancreas (for small intestine);
Epiglottis: which tips posteriorly at the pharynx to prevent food
from entering the larynx/respiratory tract.
Mesentery* (newly discovered organ that helps hold the intestines
to the posterior abdominal cavity).

Digestion starts in the mouth, where food is chewed and
mixed with saliva to form a bolus.
The bolus produced is then swallowed down the pharynx and
oesophagus via peristaltic contractions and into the stomach.
In the stomach, it is mixed with gastric juice to form a
semifluid substance called chyme, then moved to the
duodenum (small intestine).
Most of the digestion takes place in the stomach and
duodenum of the small intestine.
Water and some minerals are reabsorbed in the colon of the
large intestine. The chyme is turned to faeces. The faeces is
defecated from the anus via the rectum.

LOCATION OF ORGANS
Fig: Abdominopelvic Regions

ABDomInAl SurfACE AnAtomy CAn BE DESCrIBED whEn VIEwED from In
front of thE ABDomEn In 2 wAyS: DIVIDED Into 9 rEGIonS By two VErtICAl
AnD two horIzontAl ImAGInAry PlAnES. DIVIDED Into 4 QuADrAntS By
SInGlE VErtICAl AnD horIzontAl ImAGInAry PlAnES.

MOUTH (ORAL CAVITY)
The mouth or oral cavity is
bounded by muscles and bones:
Anteriorly – by the lips
Posteriorly – it is continuous with
the oropharynx (part of pharynx)
Laterally – by the muscles of the
cheeks
Superiorly – by the bony hard
palate and muscular soft palate
Inferiorly – by the muscular tongue
and the soft tissues of the floor of
the mouth.

SAlIVAry GlAnDS
Most animals have three major pairs of salivary glands
and hundreds of minor salivary that differ in the type of
secretion they produce:
1-Parotid glands produce a serous, watery secretion.
2-Submaxillary (mandibular) glands produce a mixed
serous and mucous secretion.
3-Sublingual glands secrete a saliva that is predominantly
mucous in character.

TONGUE
The tongue is a large, muscular organ
that occupies most of the oral cavity.
It is attached by its base to the hyoid
bone, and by thin fold of tissue called the
frenulum, to the floor of the mouth.
A groove called the terminal sulcus
divides the tongue into two parts.
• Anterior: covered by papillae (contains
some taste buds).
• Posterior: contains few small glands
and a large amount of lymphoid tissue,
the lingual tonsil. Fig: Dorsal surface of tongue & tonsils

tonGuE PAPPIlAE
Papillae are the tiny raised protrusions on the
tongue that contain taste buds. The three types of
papillae are:
1-Fungiform (mushroom like)
2-Filiform (filum - thread like)
3-Crcumvallate.
4-Folliate
Except for the filiform, these papillae allow us to
differentiate between sweet, salty, bitter, sour, and
umami (or savory) flavors.

TEETH (SKELETAL) The teeth are embedded in
the mandible and maxilla
bones.
Movement of the mandible
(lower jaw) allows chewing.
The mandible is the only
moveable bone in the jaw.
There are 20 temporary teeth.
Later, 32 permanent teeth
replace the 20.
There are incisors (8), canines
(4), premolars (8), and molars
(12).
Fig: Skeletal system of the mouth

PHARYNX
It connects to the oral cavity anteriorly, and is continuous
with the oesophagus. Food passes from the oral cavity into
the pharynx then to the oesophagus below it.
The pharynx consists of three parts:
 nasopharynx,
 oropharynx, and the
 laryngopharynx.
It prevents food from entering the nasal cavity (by the soft
palate) and the lower respiratory tract (by the epiglottis).

EPIGLOTTIS
Figs: Actions of soft palate and Epiglottis in Pharynx during swallowing

OESOPHAGUS
Also called gullet or esophagus, it
is an organ through which food
passes from the pharynx to the
stomach, aided by peristaltic
contractions, of its musculature.
It is about 25 cm long and 2 cm in
diameter, and lies in the median
plane (mediasternum) in the
thorax, anterior to the spinal
column, but posterior to the
trachea.

CONSTRICTIONS OF THE OESOPHAGUS
The oesophagus follows the curvature of the
vertebral column.
It also has 3 constrictions (narrowing), where
adjacent structures produce impressions:
1. Cervical Constriction (Upper Oesophageal
Sphincter) – where Pharynx meets
Oesophagus.
2. Thoracic (Broncho-Aortic) Constriction –
where it is first crossed by arch of aorta.
3. Diaphragmatic Constriction: where it
passes through the oesophageal hiatus of
the diaphragm at t10, before entering the
stomach.

OESOPHAGUS (contd.)
Immediately the oesophagus has
passed through the esophageal
hiatus (opening) of the diaphragm, it
curves upwards before opening into
the stomach.
This sharp angle, as well as the
sphincters at each end (e.g. cardiac
sphincter), prevents the regurgitation
(backflow) of gastric contents into the
oesophagus.
The oesophagus has thick walls consisting of the four layers/tunics common
to the digestive tract: mucosa (innermost), submucosa, muscularis, and
serosa/adventitia (outermost).

STOMACH
Fig: Anterior view of stomach and its adjacent structures

LOCATION OF THE STOMACH
It is the enlarged hollow part of
the digestive tract specialized in
the accumulation of ingested
food, and also acts as food
blender.
It is located between the
oesophagus and the small
intestine.
It is located in the epigastric,
umbilical & left hypochondriac
regions of the abdominal cavity. Gastroenterology deals with the study of
diseases of the stomach and intestines
and their associated organs

PARTS OF THE STOMACH
The stomach has four (4) parts:
 Cardiac
 Fundus
 Body
 Pylorus
The stomach is continuous with the
oesophagus at the Cardiac Sphincter,
and with the Duodenum at the Pyloric
Sphincter.
The Pyloric Sphincter guards the opening between the stomach and the
duodenum. When the stomach is inactive, the pyloric sphincter is relaxed and
open, and when the stomach contains food, the sphincter is closed.

CEllS In StomACh
Four different types of cells make up the gastric
glands:
1-Mucous cells … secrete an alkaline mucus that
protects the epithelium against shear stress and acid.
2-Parietal cells … secrete hydrochloric acid and
INTRINSIC FACTOR.
3-Chief cells … secrete pepsin, a proteolytic enzyme.
4-G cells … which are endocrine cells that synthesize
and secrete the hormone gastrin.

IntrInSIC fACtor
Intrinsic factor is a glycoprotein secreted by
parietal (humans) or chief (rodents) cells of the
gastric mucosa. In humans, it has an important role
in the absorption of vitamin B12 (cobalamin) in the
intestine, and failure to produce or utilize intrinsic
factor results in the condition pernicious anemia. A
small amount of vitamin B12 is absorbed by passive
diffusion without intrinsic factor.

SMALL INTESTINE
The small intestine is the part of the
GIT between the stomach and large
intestine.
The small intestine is continuous
with the stomach at the Pyloric
Sphincter and leads into the large
intestine at the ileocaecal valve.
It is about 2.75 – 10.49 m long. For
an average person, it is 3-5m.
It lies in the abdominal cavity
surrounded by the large intestine.

PARTS OF SMALL INTESTINE
There are 3 parts of the Small Intestine:
Duodenum: First, shortest, widest and
most fixed part (0.25m long).
Jejunum: This is the middle section of
the small intestine (about 2.5m long) –
about 2/5th
Ileum: Joins the large intestine at the
Ileocecal Junction
(3- 3.5m long) – about 3/5th
The mesentery, a double layer of peritoneum, supports and attaches the
jejunum and ileum (small intestine) to the posterior abdominal wall.

PERITONEUM & MESENTERY
The peritoneum (yellow portion) is the largest
serous membrane of the body. It is a closed sac,
containing a small amount of serous fluid, within
the abdominal cavity.
It provides attachment to organs of the GIT, and
acts as a physical barrier to localize spread of
infection.
It invaginates the stomach, small intestine, liver,
pancreas, kidney, spleen, and other pelvic
organs.
The mesentery associated with the small
Intestine is sometimes called the Mesentery Proper. There are mesenteries of
other parts, e.g. of the colon: transverse mesocolon.

The structures within the intraperitoneal space are called "intraperitoneal" (e.g., the stomach
and intestines),
the structures in the abdominal cavity that are located behind the intraperitoneal space are
called "retroperitoneal" (e.g., the kidneys).
The term subperitoneal refers to tissue that is deep to the peritoneum and includes the
extraperitoneal space, the ligaments and the mesenteries and their suspended organs . Organs
whose surfaces are covered by peritoneum are therefore subperitoneal.

Intraperitoneal Structures…
Intraperitoneal organs include the stomach, the first five centimeters and
the fourth part of the the duodenum, the jejunum, the ileum, the cecum,
the appendix, the transverse colon, the sigmoid colon, and the upper third
of the rectum.
Retroperitoneal Organs…
S = Suprarenal (adrenal) Glands.
A = Aorta/IVC.
D =Duodenum (except the proximal 2cm, the duodenal cap)
P = Pancreas (except the tail)
U = Ureters.
C = Colon (ascending and descending parts)
K = Kidneys.
E = (O)esophagus.
R = Rectum

LIVER & GALL BLADDER
The liver is an accessory digestive gland,
and largest internal organ.
It is involved in the:
• Synthesis of glucose from amino acid
• Breaking down of carbohydrates
• Synthesis of cholesterol
• Production of fat, through lipogenesis.
• Production of bile.
The bile produced is stored in the gall bladder, and secreted to the small
intestine during food digestion. The gallbladder is a saclike structure on the
inferior surface of the liver that is about 8 cm long and 4 cm wide.

PANCREAS
The pancreas is a pale grey
gland weighing about 60g. It is
about 12–15 cm long and is
situated in the
epigastric and left
hypochondriac regions of the
abdominal cavity.
It consists of a broad head, a
body and a narrow tail.
It secrets pancreatic juice
(exocrine pancreas), and insulin
and glucagon (endocrine
pancreas).

Your pancreas plays a big role in digestion.
It is located inside your abdomen, just
behind your stomach. It's about the size of
your hand. During digestion, your
pancreas makes pancreatic juices called
enzymes. These enzymes break down
sugars, fats, and starches
It's possible to live without a pancreas. But when the entire pancreas is removed, people are
left without the cells that make insulin and other hormones that help maintain safe blood
sugar levels. These people develop DIABETES (DM TYPE 2), which can be hard to manage
because they are totally dependent on insulin shots. There are a few things you must
completely avoid, such as alcohol and fried/greasy/high fat foods (such as creamy sauces,
fast food, full fat meat and dairy, and anything fried). These foods can cause your pancreas to
release more enzymes at once than it normally would, leading to an attack

LARGE INTESTINE
The Large Intestine meets the Small
Intestine at the ileocaecal valve,
then continues to the anal canal.
It is about 1.5m long and 6.5cm
wide (Small Intestine: 2.5cm).
It consists of the
Cecum (proximal end),
Appendix
Colon (ascending, descending,
sigmoid, transverse),
Rectum,
Anal canal (distal end)
Fig: Parts of the Large Intestine

SPECIAl StruCturES of lArGE IntEStInE
Three features are unique to the large intestine…
Teniae coli
Haustra
Epiploic appendages
The teniae coli are three bands of smooth muscle that make up the longitudinal
muscle layer of the muscularis of the large intestine, except at its terminal end.
The haustra refer to the small segmented pouches of bowel separated by the
haustral folds. They are formed by circumferential contraction of the inner
muscular layer of the colon. Epiploic appendages are peritoneal structures that
arise from the outer serosal surface of the bowel wall towards the peritoneal
pouch. They are filled with adipose tissue and contain a vascular
stalk. Epiploic appendagitis is a rare cause of acute lower abdominal pain.

funCtIonS of thE DIGEStIVE
SyStEm
 Ingestion,
 Mastication,
 Propulsion,
 Mixing,
 Secretion,
 Digestion,
 Absorption, and
 Elimination.

ORGAN FUNCTIONS
Ingestion, T
aste, Mastication, Digestion,
Swallowing, Communication, Protection.
Mouth
Swallowing, Breathing, Protection
Propulsion, Protection.
Pharynx
Oesophagus
Storage, Digestion, Absorption, Mixing and
Propulsion, Protection.
Stomach
Neutralization, Digestion, Absorption, Mixing and
Propulsion, Excretion, Protection.
Absorption, Storage, Mixing and Propulsion,
Protection, Excretion.
Small Intestine
Large Intestine

THANK YOU
THE DIGESTIVE SYSTEM. VICTOR EKPO. CMUL - LAGOS

MBBS (GMC)
PharmoHub Pakistan

LIVER
 The liver is
located in the upper
right-hand portion
of the abdominal
cavity, beneath the
diaphragm, and on
top of the stomach,
right kidney, and
intestines. Shaped
like a cone, the liver
is a dark reddish-
brown organ that
weighs about 3
pounds.

PORTA HEPATIS
 The porta hepatis is a deep fissure in the inferior
surface of the liver through which all the neurovascular
structures (except hepatic veins) and hepatic ducts enter or
leave the liver 1. It runs in the hepatoduodenal ligament
and contains: right and left hepatic ducts. right and left
branches of hepatic artery. CONTENTS :
 The portal vein (RT and LT branches)
 The hepatic artery (RT and LT branches)
 The hepatic ducts (RT and LT branches)
 The hepatic nervous plexus
 The lymphatic vessels

BARE AREA OF LIVER
 The bare area of the liver (nonperitoneal area) is a
large triangular area on the diaphragmatic surface
of the liver, devoid of peritoneal covering. It is
attached directly to the diaphragm by loose connective
tissue.
 The bare area of the liver is clinically important
because of the portacaval anastomosis and it
represents a site where infection can spread from the
abdominal cavity to the thoracic cavity.

INTRODUCTION…
 When the liver cells secrete bile, it is collected by a
system of ducts that flow from the liver through the
right and left hepatic ducts. These ducts ultimately
drain into the common hepatic duct. The common
hepatic duct then joins with the cystic duct from the
gallbladder to form the common bile duct.
 The organs and ducts that make and store bile (a fluid
made by the liver that helps digest fat), and release it
into the small intestine. The biliary system
includes the gallbladder and bile ducts inside and
outside the liver. Also called biliary tract.

BILE CANALICULI…
 Bile canaliculi are tiny, 1- to 2-μm wide tissue spaces
formed by the apical membranes of adjacent
hepatocytes.
 Bile canaliculi also known as bile capillaries are thin
tubes that receive bile secreted by hepatocytes. The
bile canaliculi eventually merge and form bile
ductules. The bile passes through canaliculi to the
hepatic bile ducts and then into the common hepatic
duct which drains directly into the duodenum.

BILE…
Bile is a fluid that is made and released by the liver and stored in
the gallbladder. Bile helps with digestion. It breaks down fats into
fatty acids, which can be taken into the body by the digestive tract. ...
Bile acids (also called bile salts) Bilirubin (a breakdown product or red
blood cells)
Hepatocytes produce bile by secreting conjugated bilirubin, bile
salts, cholesterol, phospholipids, proteins, ions, and water into their
canaliculi (thin tubules between adjacent hepatocytes that eventually
join to form bile ducts
 Bile is usually yellow or green.
 Bile is secreted into the small intestine where it has two effects:
 it neutralises the acid - providing the alkaline conditions needed in the
small intestine.
 it emulsifies fats - providing a larger surface area over which the lipase
enzymes can work.

COMPONENTS OF BILIARY SYSTEM
 The biliary system consists of the organs and ducts
(bile ducts, gallbladder, and associated
structures) that are involved in the production and
transportation of bile.
 From the right and left hepatic ducts, bile then flows
into the common hepatic duct. The common hepatic
duct joins the cystic duct, where the bile then flows.
The cystic duct is connected to the gallbladder. Bile
flows from the cystic duct into the common bile duct.

EXTRAHEPATIC BILIARY
SYSTEM
 RT hepatic duct
 LT hepatic duct
 Common hepatic duct
 Cystic duct
 Common bile duct
 Gallblader

PORTAL TRIAD
 The portal triad is a
TRIANGULAR area at the
liver named after its
triangular shape and its
three major
components: the hepatic
artery, the hepatic portal
vein, and the hepatic
ducts, or bile ducts. The
term, however, can be
considered a misnomer,
since it contains other
structures as well.

BILIARY TREE…
 The biliary tree is a system of vessels that directs
these secretions from the liver, gallbladder and
pancreas through a series of ducts into the
duodenum
 The ampulla of Vater is a small opening that enters
into the first portion of the small intestine, known
as the duodenum. The ampulla of Vater is the spot
where the pancreatic and bile ducts release their
secretions into the intestines.

CALLOT`S TRIANGLE
 The triangle of Calot is an important landmark whose
boundaries include the common hepatic duct medially,
the cystic duct laterally, and the inferior edge of the
liver superiorly.
 SIGNIFICANCE :
 This triangular space is dissected to allow the surgeon
to identify, divide, and ligate the cystic duct and artery.

HEPATOCYSTIC TRIANGLE
SUPERIORLY… the inferior border of
liver.
LATERALY… the cystic duct and the neck
of the gallbladder.
MEDIALLY… the common hepatic duct.

Symptoms of possible biliary
disease
 Jaundice (yellowing of the skin and whites of the eyes)
 Abdominal pain, especially in the upper right side of
the abdomen under the rib cage.
 Nausea or vomiting.
 Loss of appetite, which may result in weight loss.
 Fatigue.
 Fever or chills.
 Itching.
 Light brown urine.

DISEASES OF BILIARY SYSTEM
 Gallstones and Cholecystitis
 Gallbladder Tumors
 Choledocholithiasis
 Acute cholangitis

Gallstones and Cholecystitis
 Gallbladder stones are an extremely common disorder
and are usually asymptomatic. Some patients
experience biliary colic, an intermittent and often
severe pain in the epigastrium or right upper quadrant,
and at times between the scapula because of
temporary obstruction of the cystic duct with a
gallstone. If the cystic duct obstruction persists, the
gallbladder becomes inflamed and the patient
develops cholecystitis, an acute inflammation and
infection of the gallbladder.

ACUTE CHOLANGITIS…
 CHOLANGIOCYTES are the epithelial cells of the
bile duct.
 Acute cholangitis is bacterial infection of the extra-
hepatic biliary system. As it is caused by gallstones
blocking the common bile duct in most of the
cases, its prevalence is greater in ethnicities with high
prevalence of gallstones.

URINARY SYSTEM
DR. AhMAD AlI QUREShI
MBBS (GMC)
PharmoHub Pakistan

lEARNING oUTCoMES…
 Name
 Structures of organs of
urinary system
 Their interrelationship

GENERAl STRUCTURE AND FUNCTIoNS
oF ThE URINARY SYSTEM
● The urinary system, also known as the renal system
● The urinary system refers to the structures that produce and conduct
urine to the point of excretion.
■ Organs of the Urinary System:
■ Kidneys (2)
■ Ureters (2)
■ Urinary Bladder
■ Urethra
■ Primary organs: kidneys
■ filter waste products from the bloodstream
■ convert the filtrate into urine.
■ The Urinary Tract:
■ Includes:
■ ureters
■ urinary bladder
■ urethra
They transport the urine out of the body.

27-7
KIDNEYS: GRoSS AND SECTIoNAl
ANAToMY
■ Retroperitoneal
■ Anterior surface covered with peritoneum
■ Posterior surface against posterior abdominal
wall
■ Superior pole: T-12
■ Inferior pole: L-3
■ Right kidney ~ 2cm lower than left due to
left lobe of liver.
■ Adrenal glands on superior pole

PRoTECTED BY ThREE CoNNECTIvE TISSUE
lAYERS
●  RENAl FASCIA
 Attaches to abdominal wall
●  ADIPoSE CAPSUlE
 Fat cushioning kidney
●  RENAl CAPSUlE
Fibrous sac
Protects from trauma and infection
27-9

27-11
ANAToMY
■ Hilum: concave medial border
■ Renal sinus: internal space
■ Houses blood vessels, lymphatic vessels,
nerves
■ Houses renal pelvis, renal calyces
■ Also fat

27-12
ANAToMY
■ Sectioned on a coronal plane:
■ Renal Cortex
■ Renal Medulla
■ Divided into renal pyramids
■ 8 to 15 per kidney
■ Base against cortex
■ Apex called renal papilla

27-13
ANAToMY
■ Minor calyx:
■ Funnel shaped
■ Receives renal papilla
■ 8 to 15 per kidney, one per pyramid
■ Major calyx
■ Fusion of minor calyces
■ Major calyces merge to form renal pelvis
■ Renal Lobe
■ Pyramid plus some cortical tissue

Renal sinus
 Surrounded by renal parenchyma
 Contains blood & lymph vessels,
nerves,
urine-collecting structures
Hilus
 On concave surface
 Vessels and nerves enter and exit
27-16
● KIDNEY ANAToMY
● Renal parenchyma
● Renal pyramids
Extensions of cortex (renal columns)
divide medulla into 6 – 10 renal
pyramids
●  Pyramid + overlying cortex = Lobe
●  Point of pyramid = Papilla
●  Papilla nested in cup (minor calyx)
●  2 – 3 minor calices  Major calyx
●  2 – 3 major calices  Renal pelvis
●  Renal pelvis  Ureter

BlooD SUPPlY To ThE
KIDNEY
■ The efferent arterioles branch into one of two
types of capillary networks:
■ peritubular capillaries
■ vasa recta
■ these capillary networks are responsible for
the actual exchange of gases and nutrients
■ Peritubular capillaries: primarily in cortex
■ Vasa recta: surround the thin tubes that
project into the medulla.

27-20
NEPhRoNS
■ The functional filtration unit in the kidney.
■ Consists of the following:
■ Renal corpuscle
■ Glomerulus
■ Glomerular capsule (Bowman’s capsule)
■ Proximal convoluted tubule (PCT)
■ Nephron loop (loop of Henle)
■ Ascending loop of Henle
■ Descending loop of Henle
■ Distal convoluted tubule (DCT)
■ collectively called the renal tubule
■ In both kidneys: approximately 2.5 million nephrons.
■ Are microscopic: measure about 5 centimeters in
length.

27-21
NEPhRoNS
■ Cortical Nephrons
■ Near peripheral edge of cortex
■ Short nephron loops
■ Have peritubular capillaries
■ Juxtamedullary nephrons
■ Near corticomedullary border
■ Long nephron loops
■ Have vasa recta

27-22
URINE FoRMATIoN
■ Three processes
■ Filtration
■ Renal corpuscle: forms filtrate
■ From blood to tubule
■ Reabsorption
■ Mostly PCT
■ Water and salt: rest of nephron
■ From tubule to blood
■ Secretion
■ From blood to tubule

RENAL CORPUSLE
27-23
● Composed of a glomerulus and the Bowman's capsule.
● The renal corpuscle is the beginning of the nephron.
● It is the nephron's initial filtering component.
● The glomerulus is a capillary tuft that receives its blood supply from an
afferent arteriole of the renal circulation.
● The glomerular blood pressure provides the driving force for water and
solutes to be filtered out of the blood and into the space made
byBowman's capsule.
● The remainder of the blood passes into the efferent arteriole.
● The diameter of efferent arterioles is smaller than that of afferent
arterioles, increasing the hydrostatic pressure in the glomerulus.

● The Bowman's capsule, also called the glomerular capsule.
●  surrounds the glomerulus.
● It is composed of a visceral inner layer formed by specialized cells
called podocytes.
● Parietal outer layer composed of simple squamous epithelium
● Fluids from blood in the glomerulus are filtered through the
visceral layer of podocytes, resulting in the glomerular filtrate.
27-24

Renal tubule
●  Leads from glomerular capsule
●  Ends at tip of medullary pyramid
●  ~3 cm long
●  Four major regions
●  Proximal convoluted tubule
●  Nephron loop
●  Distal convoluted tubule
●  Collecting duct
26

27-28
PRoxIMAl CoNvolUTED TUBUlE
● Arises from glomerular capsule
● Longest, most coiled region
● lies in cortex
● lined by simple cuboidal epithelium with brush
borders which help to increase the area of absorption
greatly.
● Prominent microvilli
● Function in absorption

27-29
NEPhRoN looP (looP oF hENlE)
■ originates at end of proximal convoluted tubule
■ projects toward and/or into the medulla.
■ Each loop has two limbs.
■ descending limb:
■ from cortex toward and/or into the medulla
■ ascending limb:
■ returns back to the renal cortex

ASCENDING lIMB oF looP oF
hENlE
● The ascending limb of loop of Henle is divided into 2 segments:
●  Lower end of ascending limb is very thin and is lined by simple squamous
epithelium.
● The distal portion of ascending limb is thick and is lined by simple cuboidal
epithelium.
● Thin ascending limb of loop of Henle
● Thick ascending limb of loop of Henle (enters cortex and becomes DCT-distal
convoluted tubule.)
●  Thick segments
Active transport of salts
High metabolism, many mitochondria
●  Thin segments
Permeable to water
Low metabolism

DISTAl CoNvolUTED TUBUlE
(DCT)
●  Coiled, distal to nephron loop
●  Shorter than PCT
●  Less coiled than PCT
●  Very few microvilli
●  Contacts afferent and efferent arterioles
●  Contact with peritubular capillaries
31

CollECTING DUCT

● DCTs of several nephrons empty into a
collecting duct
● Passes into medulla
● Several merge into papillary duct (~30
per papilla)
● Drain into minor calyx
32

27-33
INNERvATIoN oF ThE KIDNEY
■ Innervated by a mass of autonomic nervous system
fibers
■ called the renal plexus.
■ The renal plexus
■ accompanies each renal artery
■ enters the kidney through the hilum.

27-35
URETERS
■ long, fibromuscular tubes
■ conduct urine from the kidneys to the urinary
bladder.
■ average 25 centimeters in length
■ retroperitoneal.
■ ureters originate at the renal pelvis
■ extend inferiorly to enter the posterolateral wall of
the base of the urinary bladder.
■ wall is composed of three concentric tunics.
■ mucosa
■ muscularis
■ adventitia.

27-37
URINARY BlADDER
■ The urinary bladder:
■ expandable, muscular container
■ serves as a reservoir for urine
■ positioned immediately superior and posterior to the pubic
symphysis.
■ in females
■ the urinary bladder is in contact with the uterus posterosuperiorly
and with the vagina posteroinferiorly.
■ in males
■ it is in contact with the rectum posterosuperiorly and is
immediately superior to the prostate gland.
■ is a retroperitoneal organ.
■ when empty exhibits an upside-down pyramidal shape and lies
in pelvic region
■ Filling with urine distends it superiorly until it assumes an oval
shape and lies in abdomen

27-38
WAll oF
BlADDER
 MUCoSA -
TRANSITIoNAl
EPIThElIUM
 MUSCUlAR
lAYER -
DETRUSoR
MUSClE
 ADvENTITIA

TRIGONE
A triangular body
part specifically a
smooth triangular area
on the inner surface of
the bladder limited by
the apertures of the
ureters and urethra.
39

27-40
MICTURITIoN (URINATIoN)
● Urination (micturition)
● ~200 ml of urine held
●  Distension initiates desire to void
●  Internal sphincter relaxes involuntarily
●  Smooth muscle
●  External sphincter voluntarily relaxes
●  Skeletal muscle
●  Poor control in infants
●  Bladder muscle contracts
●  Urine forces through urethra

WhAT ARE ThE STEPS oF MICTURATIoN?
● Normal urination (micturition) occurs in the following
stages:
● Urine is made in the kidneys.
● Urine is stored in the bladder.
● The sphincter muscles relax.
● The bladder muscle (detrusor) contracts.
● The bladder is emptied through the urethra and urine is
removed from the body.
41

27-43
UREThRA
●  Conveys urine from body
●  Internal urethral sphincter
Retains urine in bladder
Smooth muscle, involuntary
●  External urethral sphincter
Provides voluntary control over voiding
of urine

FEMAlE UREThRA
■ Has a single function:
■ to transport urine from the urinary bladder to the vestibule,
an external space immediately internal to the labia minora
■ 3 to 5 centimeters long, and opens to the outside of
the body at the external urethral orifice located in the
female perineum.

MAlE UREThRA
■ Urinary and reproductive functions:
■ passageway for both urine and semen
■ Approximately 18 to 20 centimeters long.
■ Partitioned into three segments:
PRoSTATIC UREThRA 2.5 cm long, urinary bladder to
prostate.
MEMBRANoUS UREThRA is the shortest 0.5 cm, passes
through floor of pelvic cavity
PENIlE UREThRA 15 cm long, passes through penis

MBBS (GMC)
1
FEMALE REPRODUCTIVE
ANATOMY
PharmoHub Pakistan

Kindly recite Durood e Pak…
2

3
External
Genitalia
(vulva))
Mons Pubis
Labia
Majora
Labia
Minora
Vestibule
Clitoris

4
EXTERNAL GENTILIA
● The vuLvA refers to those parts that are outwardly visible
● The vulva includes:
● Mons pubis
● Labia majora
● Labia minora
● Clitoris
● Urethral opening
● Vaginal opening
● Perineum

6
MONS PuBIS
● The triangular mound of fatty tissue that
covers the pubic bone
● It protects the pubic symphysis
● During adolescence sex hormones trigger the
growth of pubic hair on the mons pubis
● The female pubic hair is horizontal straight in
its upper Border and The male pubic hair is
triangular in its upper border

8
LABIA MAJORA
● The labia Majora are two rounded, folds of tissue
that extended from the mons pubis to the perineum
● Referred to as the outer lips
● They have a darker pigmentation
● The Labia Majora:
● Protect the introitus (vaginal and urethral openings)
● Are covered with hair and sebaceous glands
● Tend to be smooth, moist, and hairless

10
LABIA MINORA
● Referred to as the “inner lips”
● Made up of erectile, connective tissue that
darkens and swells during sexual arousal
● Located inside the labia majora
● They are more sensitive and responsive to
touch than the labia majora
● The labia minora tightens during intercourse

12
CLITORIS
● Highly sensitive organ composed of nerves,
blood vessels, and erectile tissue
● Located under the prepuce
● It is made up of a shaft and a glans
● Becomes engorged with blood during sexual
stimulation
● Key to sexual pleasure for most women
● Urethral opening is located directly below clitoris

14
vAGINAL OPENING (INTROITuS)
● Opening may be covered by a thin sheath
called the hymen
● Using the presence of an intact hymen for
determining virginity is erroneous
● Some women are born without hymens
● The hymen can be perforated by many
dIffERENT events.S

15
PERINEuM
● The muscle and tissue located between the
vaginal opening and anal canal
● It supports and surrounds the lower parts of the
urinary and digestive tracts
● The perinium contains an abundance of nerve
endings that make it sensitive to touch
● An episiotomy is an incision of the perinium used
during childbirth for widening the vaginal opening

HYMEN
17
The hymen is a remnant tissue just
inside the opening of the vagina that's
left over from how the vagina forms
during embryonic development. It's
commonly seen as a small amount of
extra tissue in a crescent-shape or ring-
like configuration (1mm) around the
edge of the vaginal opening.

REASONS Of
hyMEN
BREAkING…
● The hymen can stretch
or even tear during
many intense physical
activities like cycling,
swimming, horse riding,
etc. Use of tampons
and inserting something
in your vagina (fingers,
sex toys, etc) can also
stretch the hymen.
18

hOw dO I
kNOw If My
hyMEN IS
BROkEN…??
● Your hymen does not
completely cover your
vaginal opening – a hole
is normal. When you
have sex, your hymen
does not 'break or pop'
– it stretches, which
may cause a small tear.
You cannot tell by
looking at a hymen
whether sex has
occurred (consensual or
non-consensual)
19

21
Internal
Genitalia
Vagina
Uterus
Ovary
Fallopian
Tubes

23
vAGINA
● The vagina connects the cervix to the external genitals
● It is located between the bladder and rectum
● It functions :
● As a passageway for the menstrual flow
● For uterine secretions to pass down through the introitus
● As the birth canal during labor
● With the help of two Bartholin’s glands becomes
lubricated during Sexual intercourse

24
● The cervix connects the uterus to the vagina
● The cervical opening to the vagina is small
● This acts as a safety precaution against foreign
bodies entering the uterus
● During childbirth, the cervix dilates to accommodate
the passage of the fetus
● This dilation is a sign that labor has begun

28
uTERuS
● Commonly referred to as the womb
● A pear shaped organ about the size of a clenched fist
● It is made up of the endometrium, myometrium and
perimetrium
● Consists of blood-enriched tissue that sloughs off
each month during menstrual cycle
● The powerful muscles of the uterus expand to
accommodate a growing fetus and push it through
the birth canal

Layers of
uterus
● The endometrium is the
inner layer that lines the
uterus. It is made up of
glandular cells that
make secretions.
● The myometrium is the
middle and thickest
layer of the uterus wall.
It is made up mostly of
smooth muscle.
● The perimetrium is the
outer serous layer of the
uterus.
30

32
fALLOPIAN TuBES
● Serve as a pathway for the ovum to the uterus
● Are the site of fertilization by the male sperm
● Often referred to as the oviducts or uterine
tubes
● Fertilized egg takes approximately 6 to 10
days to travel through the fallopian tube to
implant in the uterine lining

Parts of
fallopian
tube
● Fimbriae
● Infundibulam
● Ampula
● Isthmus
33

36
OvARIES
● The female gonads or sex glands
● They develop and expel an ovum each month
● A woman is born with approximately 400,000 immature
eggs called follicles
● During a lifetime a woman release @ 400 to 500 fully
matured eggs for fertilization
● The follicles in the ovaries produce the female sex
hormones, progesterone and estrogen
● These hormones prepare the uterus for implantation of
the fertilized egg

41
BREASTS
● Organs of sexual arousal
● Contain mammary glands
● Consist of connective tissue that
serves as support
● Each breast contain 15-25 clusters
called lobes
● Each lobule is connected by ducts
that open into the nipples
● The nipples are made up of erectile
tissue
● The pigmented around the nipples
are called the areola
● Breast size is determined primarily
by heredity
● Size also depends on the existing
fat and glandular tissue
● Breasts may exhibit cyclical
changes, including increased
swelling and tenderness prior to
menstruation
● Benign breast changes refer to
fibrocystic disease
● Lumps or masses that are
noncancerous

Male RepRoductive SySteM
dR. ahMad ali QuReShi
MBBS (GMc)
PharmoHub Pakistan

intRoduction…
• The male reproductive system is mostly located
outside of the body. These external organs include:
• Penis
• Scrotum
• Testicles
• Internal organs include:
• Vas deferens
• Prostate
• Urethra
• The male reproductive system is responsible for sexual
function, as well as urination.

FunctionS oF Male
RepRoductive SySteM
• They produce, maintain and transport sperm
(the male reproductive cells) and semen (the
protective fluid around sperm).
• They discharge sperm into the female
reproductive tract.
• They produce and secrete male sex hormones.

how do the teSteS deScend?
Testicles form in the abdomen during fetal
development. During the last couple of months of
normal fetal development, the testicles gradually
descend from the abdomen through a tube-like
passageway in the groin (inguinal canal) into the
scrotum. With an undescended testicle, that
process stops or is delayed

acceSSoRy GlandS
The male accessory glands synthesize and secrete a complex
mixture of proteins, carbohydrates, lipids, and amino acids
that are transferred to the female during copulation. The
primary function of the accessory gland products is to
facilitate sperm transfer to the female.
Accessory glands are specialized structures found in males
that produce fluids essential for the motility, nourishment and
protection of sperm
The accessory glands of the male reproductive system are
the seminal vesicles, prostate gland, and the bulbourethral
glands. These glands secrete fluids that enter the urethra.

THE PROSTATE IS LOCATED JUST BELOW THE
BLADDER AND IN FRONT OF THE RECTUM. IT
IS ABOUT THE SIZE OF A WALNUT AND
SURROUNDS THE URETHRA (THE TUBE THAT
EMPTIES URINE FROM THE BLADDER).
The inferior vesical artery is the major blood
supply for the prostate, and it also receives blood
supply from the middle rectal and internal
pudendal arteries. Veins around the prostate form
the prostatic plexus which drains into internal iliac
veins

EndocrinE
systEm
MBBS (GMC)
PharmoHub Pakistan

Endocrinology…
● Endocrinology is a branch of biology and medicine focusing on the
endocrine system and its secretion of hormones
● There are 2 types of glands
● Endocrine glands are ductless glands of the endocrine system that
secrete their products, hormones, directly into the blood. The major
glands of the endocrine system include the pineal gland, pituitary
gland, pancreas, ovaries, testes, thyroid gland, parathyroid gland,
hypothalamus and adrenal glands.
● Exocrine gland - A gland that makes substances such as sweat,
tears, saliva, milk, and digestive juices, and releases them through a
duct or opening to a body surface. Examples of exocrine glands
include sweat glands, lacrimal glands, salivary glands, mammary
glands, and digestive glands in the stomach, pancreas, and
intestines.

HormonEs…
● Hormones are chemical substances that act like messenger
molecules in the body. After being made in one part of the
body, they travel to other parts of the
● There are three major types of hormones.
● Protein hormones (or polypeptide hormones) are made of
chains of amino acids. An example is ADH (antidiuretic
hormone) which decreases blood pressure.
● Steroid hormones are derived from lipids....
● Amine hormones are derived from amino acids

lEarning objEctivEs….
Pituitary Gland
Thyroid Gland
Parathyroid Gland
Adrenal Gland

HyPotHalamUs &
PitUitary gland
location: Small but complex appendage that
sits at the base of the brain – in the sella
turcica – most median depression in the
medial cranial fossa of the sphenoid bone.
• Pituitary lies just inferior to hypothalamus.
• Hypothalamus and Pituitary connected by
stalk containing nerve fibers and blood
vessels.
• Pituitary composed of two lobes: ANTERIOR
PITUITARY and POSTERIOR PITUITARY.

Pituitary gland (hypophysis) is a round
organ about the size of a pea (~1 cm in
diameter), located behind the bridge of
the nose at the base of the brain
Divided into a posterior and anterior
portion.
Posterior pituitary is also known as the
neurohypophysis, because it is
continuous with the brain.
Anterior pituitary is also known as the
adenohypophysis, because it acts more
as a gland

Pituitary gland reveals that it composed
of two distinctive parts:
● The anterior pituitary or adenohypophysis is a
classical gland composed predominantly of cells that
secrete protein hormones.
● The posterior pituitary or neurohypophysis is not a
separate organ, but an extension of the
hypothalamus. It is composed largely of the axons of
hypothalamic neurons which extend downward as a
large bundle behind the anterior pituitary. It also
forms the so-called pituitary stalk, which appears to
suspend the anterior gland from the hypothalamus.
● The hypophysis is made of two parts: the
adenohypophysis contains the anterior and
intermediate lobes, and the neurohypophysis
contains the posterior lobe

HyPotHalamUs & PitUitary gland
Embryological Derivation:
• Hypothalamus is an outgrowth of brain,
neural ectoderm.
• Posterior Pituitary is an outgrowth of
hypothalamus, neural ectoderm.
• Anterior Pituitary develops as a superiorly
directed outgrowth of roof of mouth,
endoderm.

Definition of Rathke's pouch
A pouch of ectoderm that grows out from the upper surface
of the embryonic stomodeum and gives rise to the
adenohypophysis of the pituitary gland

HYPOTHALAMUS & PITUITARY GLAND
Innervation: Part of brain or very close to it in
case of pituitary. Some hypothalamic
neurons secrete neurohormones – they pass
down connecting stalk to terminate close to
the capillaries serving posterior pituitary.
artErial sUPPly: the superior hypophyseal
artery (a branch of the internal carotid artery)
vEnoUs drainagE: cavernous venous sinus
and the adjacent dural venous sinuses

HYPOTHALAMUS HORMONES
(FUNCTION)
• Hypothalamic hormones enclosed in
vesicles that move down axon and
accumulate near terminal ends that are close
to the posterior pituitary’s capillaries.
• In response to an action potential–
hormones are released from vesicles (much
like a neurotransmitter), in this case into
venous capillaries.

HYPOTHALAMUS HORMONES (FUNCTION)
Most hormonal interactions of the hypothalamus-
pituitary complex follow a common pattern:
1. A hypothalamic hormone effects control over the
secretion of an anterior pituitary hormone;
1. The corresponding anterior pituitary hormone
controls secretion of the hormone of another
endocrine gland; and
1. That secretion of that gland affects other target
tissues/organs.

HYPOTHALAMUS HORMONES (FUNCTION)
So...
Hypothalamic hormones can have effect of
stimulating or inhibiting the release of
anterior pituitary hormones.
Called RELEASING HORMONES (“RH”) or
INHIBITING HORMONES (“IH”) respectively.

HYPOTHALAMIC HORMONES (FUNCTIONS)
Includes two peptide hormones: OXYTOCIN and
VASOPRESSIN (also called antidiuretic hormone, or ADH).
OXYTOCIN –
initiates labor
stimulates mammary glands to release milk
Stimulates uterine contractions in activities other than labor
VASOPRESSIN (ADH) – decreases urine output.
RELEASING HORMONES – stimulate release of anterior
pituitary hormones.
INHIBITING HORMONES – inhibit release of anterior pituitary
hormones.

POSTERIOR PITUITARY GLAND HORMONES
Oxytocin and Vasopressin are manufactured in the
hypothalamus, but released in the posterior pituitary.

ANTERIOR PITUITARY GLAND HORMONES
GROWTH HORMONE (GH) – regulates growth; affects protein, fat and
carbohydrate metabolism.
THYROID STIMULATING HORMONE (TSH) – controls secretion of
thyroxin.
ADRENOCORTICOTROPIC HORMONE (ACTH) – controls secretion of
hormones released by adrenal cortex.
FOLLICLE-STIMULATING HORMONE (FSH) – in females, stimulates
magturation of egg cells and estrogen secretion by ovaries.
LUTENIZING HORMONE (LH) – in males, stimulates secretion of
testosterone and sperm production by testes. In females, stimulates
release of ovum by ovary.
MELANOCYTE-STIMULATING HORMONE (MSH) – along with ACTH,
affects pigment release in skin.
PROLACTIN (PRL) – stimulates milk production.

Note Pituitary
Portal System!!

HyPotHalamic HyPoPHysEal Portal
systEm…
● The hypothalamic–hypophysial portal system is the conduit that
connects the brain to the anterior pituitary. The portal system is made
up of two capillary beds, one in the median eminence and the other in
the anterior pituitary
● Its main function is the transport and exchange of hormones to allow a
fast communication between both glands
● In response to signals from the same hypothalamic neurons, the
hormones are released from the axon terminals into the bloodstream.
● Oxytocin. ...
● Antidiuretic Hormone (ADH) ...
● Growth Hormone. ...
● Thyroid-Stimulating Hormone. ...
● Adrenocorticotropic Hormone. ...
● Follicle-Stimulating Hormone and Luteinizing Hormone. ...
● Prolactin.

● The hypophyseal portal system is a system of
blood vessels in the microcirculation at the base
of the brain, connecting the hypothalamus with
the anterior pituitary. Its main function is to
quickly transport and exchange hormones
between the hypothalamus arcuate nucleus and
anterior pituitary gland

Anatomical Location…
● The thyroid gland is located in the anterior neck
and spans the C5-T1 vertebrae. It consists of two
lobes (left and right), which are connected by a
central isthmus anteriorly – this produces a
butterfly-shape appearance.
● The lobes of the thyroid gland are wrapped around
the cricoid cartilage and superior rings of
the trachea. The gland is located within
the visceral compartment of the neck (along with
the trachea, esophagus and pharynx). This
compartment is bound by the pretracheal fascia.

Overview
of the
position of
the thyroid
gland in
the neck

The thyroid gland consists of two lobes connected by a central
isthmus. It is wrapped around the cricoid cartilage and trachea
anteriorly.

Development of thyroid gland…
● The thyroid gland is the first of the body's endocrine
glands to develop, on approximately the 24th day of
gestation. This occurs under the influence of fibroblast
growth factor signaling pathways. The thyroid originates
from two main structures: the primitive pharynx and the
neural crest

Anatomical Relations…
● The thyroid gland is closely associated with
numerous other structures in the anterior neck:
● Anteriorly – infrahyoid muscles
● Laterally – carotid sheath
● Medially –
○ Organs – larynx, pharynx, trachea and
oesophagus
○ Nerves – external laryngeal and recurrent
laryngeal

Arterial Supply
● The arterial supply to the thyroid gland is via two
main arteries:
● Superior thyroid artery – arises as the first branch
of the external carotid artery.
● Inferior thyroid artery – arises from the
thyrocervical trunk (a branch of the subclavian
artery).
● In a small proportion of people (around 10%) there is
an additional artery present – the thyroid ima artery.
It arises from the brachiocephalic trunk and supplies
the anterior surface and isthmus of the thyroid gland

Venous Drainage…
● Venous drainage is carried by the superior,
middle, and inferior thyroid veins, which
form a venous plexus around the thyroid
gland.
● The superior and middle veins drain into
the internal jugular vein.
● The inferior empties into the
brachiocephalic vein.

● nErvE sUPPly
● The gland
receives sympathetic
nerve supply from the
superior, middle and
inferior cervical ganglion of
the sympathetic trunk. The
gland receives
parasympathetic nerve
supply from the superior
laryngeal nerve and the
recurrent laryngeal nerve
(Branches of vagus nervs)
● lymPHatic
drainagE
● The lymphatic
drainage of the
thyroid is to
the paratracheal a
nd deep cervical
nodes.

Functions of thyroid gland…
● The thyroid gland is a vital hormone gland: It plays a major role
in the metabolism, growth and development of the human
body. It helps to regulate many body functions by constantly
releasing a steady amount of thyroid hormones into the
bloodstream.
● The thyroid gland produces hormones that regulate the body's
metabolic rate controlling heart, muscle and digestive
function, brain development and bone maintenance. Its
correct functioning depends on a good supply of iodine from
the diet.
● The thyroid gland releases triiodothyronine (T3) and thyroxine
(T4) and Calcitonin. These hormones play an important role in
regulation of your weight, energy levels, internal temperature,
skin, hair, nail growth, and more.

Clinical Information…
● Recurrent Laryngeal Nerve
● The left and right recurrent laryngeal nerves lie in close proximity
to the thyroid gland and care must be taken not to damage them
during thyroid surgery.
● They branch from their respective vagus nerve within the chest and
hook around the right subclavian artery (right RL nerve), or the arch
of aorta (left RL nerve).
● The recurrent laryngeal nerve then travels back up the neck,
running between the trachea and oesophagus in
the tracheoesophageal groove. It then passes underneath
the thyroid gland to innervate the larynx.

● The parathyroid glands are
endocrine glands located in
the anterior neck.
● They are responsible for the
production of parathyroid
hormone (PTH), which acts to
increase the level of serum
calcium.

Anatomical Location
● The parathyroid glands are usually located on the
posterior aspect of the thyroid gland. They are flattened
and oval in shape – situated external to the thyroid gland
itself but within the pretracheal fascia.
● Most individuals have four parathyroid glands, although
variation in number (from two to six) is common:
● sUPErior ParatHyroid glands (x2) – derived from
the fourth pharyngeal pouch. They are located at the
middle of the posterior border of each thyroid lobe.
● infErior ParatHyroid glands (x2) – derived from
the third pharyngeal pouch. The inferior parathyroid
glands are usually found near the inferior poles of the
thyroid gland.

VASCULATURE…
● The vascular supply is similar to that of the thyroid
gland.
● Arterial supply is chiefly via the inferior thyroid artery (as
this artery supplies the posterior aspect of the thyroid
gland – where the parathyroids are located). Collateral
arterial supply is from the superior thyroid artery and
thyroid ima artery.
● Venous drainage is into the superior, middle, and inferior
thyroid veins

Nerves…
The parathyroid glands have an extensive
supply of sympathetic nerves derived
from thyroid branches of the
cervical ganglia.
Note: these nerves are vasomotor, not
secretomotor – endocrine secretion of
parathyroid hormone is under hormonal
control.

The lymphatic
drainage from the
parathyroid
glands is to
the paratracheal a
nd deep cervical
nodes

Development…
Like thyroid gland, develop
from endodermal thickening
in floor of early pharynx and
epithelium of 3rd and 4th gill
slit pouches.

Functions of Parathyroid glands…

Parathyroid Glands and Hypocalcaemia
● Due to their location on the posterior aspect of
thyroid gland, the parathyroid glands are at a
high risk of being damaged or removed
inadvertently during thyroid surgery.
● This can result in an acute drop in serum
calcium – hypocalcaemia. Clinical features
include tetany, muscle cramps and paraesthesia
of the fingers, toes, and mouth.
● Because of this risk, it is usually standard post-
operative practice to check the parathyroid
hormone and serum calcium in all patients
following thyroid surgery.

During surgery on the thyroid gland, the
parathyroid glands must be identified and
preserved.

ADRENAL GLANDS
MBBS (GMC)
PharmoHub Pakistan

Adrenal Gland:
 Adrenal glands also known as Supra adrenal
glands
 Located at the top of the kidney
 Right gland is triangular shape, while left is
semilunar shaped
 The of gland is about 4 grms

Anatomical Location and Relations
 The adrenal glands are located in the posterior
abdomen, between the superomedial kidney and
the diaphragm. They are retroperitoneal, with
parietal peritoneum covering their anterior surface
only.
 Perinephric (or renal) fascia encloses the adrenal
glands and the kidneys. This fascia attaches the
glands to the crura of the diaphragm. They are
separated from the kidneys by the perirenal fat.

Right adrenal gland Left adrenal gland
Anterior Posterior Anterior Posterior
•Inferior vena
cava
•Right lobe of the
liver
•Right crus of the
diaphragm
•Stomach
•Pancreas
•Spleen
•Left crus of the
diaphragm

Parts of adrenal gland:
 Each adrenal gland has two distinct structures
 Adrenal cortex – derived from the embryonic
mesoderm.
 Adrenal medulla– derived from the ectodermal neural
crest cells.
 Both parts produces hormones

Zones of adrenal cortex:
 Adrenal cortex is divided into three zones
 Zona glomerulosa (which secretes
mineralocorticoids)
 Zona fasciculata (which secretes glucocorticoids and
adrenal androgens)
 Zona reticularis (which secretes glucocorticoids and
adrenal androgens, but in small quantities)

 The medulla lies in the centre of the gland, and is
dark brown in colour. It contains chromaffin cells,
which secrete catecholamines (such as adrenaline)
into the bloodstream in response to stress.
 These hormones produce a ‘flight-or-fight‘
response. Chromaffin cells also secrete enkephalins
which function in pain control.
Medulla

VASCULATURE…
 The adrenal glands have a rich blood supply via three
main arteries:
 Superior adrenal artery – arises from the inferior
phrenic artery
 Middle adrenal artery – arises from the abdominal
aorta.
 Inferior adrenal artery – arises from the renal arteries.
 Right and left adrenal veins drain the glands. The right
adrenal vein drains into the inferior vena cava, whereas
the left adrenal vein drains into the left renal vein.

 The adrenal glands are
innervated by the coeliac
plexus and greater
splanchnic nerves.
 Sympathetic innervation to
the adrenal medulla is via
myelinated pre-synaptic
fibres, mainly from the
T10 to L1 spinal cord
segments.
 Lymph drainage is to
the lumbar lymph nodes
by adrenal lymphatic
vessels. These vessels
originate from two
lymphatic plexuses –
one deep to the capsule,
and the other in the
medulla.
Innervation Lymphatic Drainage

According to function:
 According to functions adrenocortical hormones can
be divided into three categories
 Glucocorticoids
 Mineralo-corticoids
 Cortical sex hormones

Conti…
 Glucocorticoids:
 Cortisol
 Cortisone
 Corticosterone
 Mineralo-corticoids:
 Aldosterone
 Corticosterone,
 11-deoxycortisol
 11-deoxy-Corticosterone
 Cortical sex hormones

ADRENAL GLAND
Adrenal Cortex, Function :
MINERALOCORTICOIDS – regulate sodium
retention and potassium loss.
GLUCOCORTICOIDS – act as anti-inflammatory
agents; affect metabolism of food.
ANDROGENS – regulates control over rapid
growth spurts in preadolescents.
Adrenal Medulla, Function :
ADRENALINE (EPINEPHRINE) – increases heart
rate and blood pressure.
NORADRENALINE (NOREPINEPHRINE) –
constricts arterioles.

THE NERVOUS SYSTEM
MBBS (GMC)
PharmoHub Pakistan

OBJECTIVES
 At the end of lecture student should be able to
answer
 What is central and peripheral nervous system
 How we classify the nervous system.

NERVOUS SYSTEM
 A system that controls all of the activities of the
body.
 The nervous system is made of:
 The brain The spinal cord
 The nerves The senses

CENTRAL NERVOUS SYSTEM
 The Central Nervous System is made of the brain
and the spinal cord.
 The Central Nervous System
controls everything in the body.

PERIPHERAL NERVOUS SYSTEM
 The Outer Nervous System is made of the nerves,
ganglia and the sense organs.
 Nerves Sense organ

CELLS OF CENTRAL
NERVOUS SYSTEM

NEURONS
 excitable nerve cell
 structural and functional
units of nervous system
 responsible for the
conduction of impulses
 Concerned with
reception, integration &
transformation of
information received.
composed of
Cell body
Dendrites
Axon

 Dendrites
 Dendrite spines
 Cell body/ peri karyon:
 Nucleus, trophic centre
 Organelles, Nissl granules
 Neurofilaments (neurofibrils)
 Lipofuscin
 Axon
 Axon hillock
 Axolemma
 axoplasm
NEURON

 STRUCTURAL:
 Unipolar or Pseudounipolar
 Bipolar
 Multipolar
 FUNCTIONAL:
 Motor/ receptor
 Sensory/ receptor
 Interneurons/ internuncial
. According to length of axon
Golgi type 1
Golgi type 2
CLASSIFICATION

 The Neuroglia are a group of supportive cells for the
neurons. Further, they maintain the myelin sheath,
provide nutrient support. Moreover, they also retain
homeostasis. It is within the CNS and PNS.
 It offers essential nutrients. It includes oxygen to
neurons.
 Next, it also helps create the myelin sheath. The
sheath is important in the functioning of the nervous
system. It promotes and speeds up the electrical
impulse conduction. It does so by wrapping around the
axons.
 Further, it also helps to maintain homeostasis within
the neurons. Homeostasis is how a cell maintains a
stable internal environment despite disturbances.
 It destroys pathogens. It helps protect the neurons.
 Finally, it also provides structural stability. It forms a
support structure that the neurons can inhabit.

ASTROCYTES - PROVIDE FOR THE ENERGY
AND OTHER METABOLIC NEEDS OF NEURONS
AS WELL AS GIVING NERVOUS TISSUE
STRUCTURAL SUPPORT. WHEN NEURONS OF
THE BRAIN OR THE SPINAL CORD ARE
INJURED AND DESTROYED, THEY ARE
REPLACED WITH SCAR TISSUE MADE UP OF
ASTROCYTES (A PROCESS CALLED GLIOSIS).

MICROGLIA - PHAGOCYTIC CELLS,
SIMILAR TO MACROPHAGES, THAT
PERFORM A HOUSEKEEPING
FUNCTION BY REMOVING DEAD
CELLULAR MATERIAL AND BACTERIA
FROM THE CNS.

EPENDYMAL CELLS - CELLS THAT LINE
THE CEREBRAL SPINAL FLUID (CSF)
CONTAINING CAVITIES OF THE BRAIN
- THE VENTRICLES. CSF IS
SECRETED BY A SPECIALIZED SUBSET
OF EPENDYMAL CELLS IN THE
WALLS OF THE VENTRICLES OF THE
BRAIN CALLED THE CHOROID PLEXUS.

OLIGODENDROCYTES - CELLS
RESPONSIBLE FOR MYELINATION OF
AXONS WITHIN THE CENTRAL
NERVOUS SYSTEM.

SCHWANN CELLS - GLIAL CELLS THAT
MYELINATE THE AXONS OF PERIPHERAL
NERVES. THESE CELLS WRAP THEIR
CYTOPLASM IN A SPIRAL FASHION
AROUND SHORT SEGMENTS OF AXONS.
BECAUSE THE MYELIN SHEATH IS
FORMED FROM NUMEROUS SCHWANN
CELLS ARRANGED SEQUENTIALLY
ALONG THE AXON, THERE ARE GAPS
BETWEEN ADJACENT MYELINATING
CELLS PRODUCING MYELIN-FREE AREAS
OF AXON CALLED NODES OF RANVIER.
THESE PLAY AN IMPORTANT ROLE IN
NERVE IMPULSE CONDUCTION.

 Oligodendrocytes:
Myelination in CNS
 Schwann cells:
myelination in PNS
 Astrocytes:
bind neurons to capillaries &
pia matter
 Fibrous (in white matter)
 Protoplasmic (in grey matter)
 Ependymal :
 Microglia:
phagocytic, role in immunity &
inflammation
NEUROGLIA

SUPPORTING CELLS
 Astrocytes
 Microglial cells
 Oligodendrocytes
 Ependymal cells

 neuronal cell bodies,
 dendrites
 unmyelinated axons
 Glial
cells and capillaries
WHITE MATTER GRAY MATTER
 consists mostly of
 glial cells
 myelinated axons

CENTRAL NERVOUS SYSTEM
 Brain
 Spinal cord
 Grey matter
 White matter
 Tracts
 Laminiscus

CRANIAL NERVE
 CN I – Olfactory
 CN II – Optic
 CN III – Oculomotor
 CN IV – Trochlear
 CN V – Trigeminal
 CN VI – Abducens
 CN VII – Facial
 CN VIII -Vestibulocochlear
 CN IX – Glossopharyngeal
 CN X – Vagus
 CN XI – Spinal accessory
 CN XII – Hypoglossal

SPINAL NERVE
 Cervical nerves C1-C8
 Thoracic nerves T1-
T12
 Lumber nerve L1-L5
 Sacral nerve S1-S5
 Coccygeal nerve C0

NERVE GANGLIA
 Aggregation of nerve
cell body
 Outside CNS
 Associated with
peripheral nerve
 Craniospinal (sensory)
 Autonomic ganglia

SPINAL NERVE
 Dorsal root
 Ventral root
 Dorsal root ganglion

FORMATION OF SPINAL NERVE
 Dorsal root
 Ventral root
 Dorsal root ganglion
 Ventral rami
 Dorsal rami

REFLEX
 A reflex action, also known as a reflex, is an
involuntary and nearly instantaneous
movement in response to a stimulus. When a
person accidentally touches a hot object, they
automatically jerk their hand away without
thinking. ... The path taken by the nerve
impulses in a reflex is called a reflex arc.
 An automatic reaction that happens without
thinking about it.
 A reflex happens quickly in less than a second.

REFLEX ARC
 Functional unit of nervous system.
 Components;
 Receptors
 Affarent neuron or sensory neurons
 Reflex center
 Efferent neuron or motor neuron
 Effectors

Parts Sympathetic Parasympathetic
Origin Thoracolumber Craniosacral
Situation of
ganglionic cell
In paravertebral and
prevertebral
sympathetic ganglion
On/ in the organ of
supply
Length of post
ganglionic fibers
Very long Very short
Types of nerve ending Adrenergic Cholenergic
Nature of control Wide spread and
diffuse. Combat acute
emergencies
Discreate and
isolated. Combat long
term emergencies
Metabolic effects Catabolic , energy
consuming
Anabolic, energy
sparing

ANATOMICAL…
CNS:
Brain and spinal cord
PNS:
Cranial and spinal nerves

FUNCTIONAL…
SOMATIC:
controls voluntary activities.
AUTONOMIC
controls involuntary activities
ENTERIC NERVOUS SYSTEM (ENS)/ GUT BRAIN/
MINIBRAIN
Innervation of gut most probably heart and
respiratory system
Neurons present in walls of GIT, pancreas and gall
bladder
Neurons arise from neural crest cell

EMBRYOLOGICAL…
PROSENCEPHALON/ FORE BRAIN
Telencephalon; cerebral hemisphere
Diencephalon
Pars dorsalis; thalamus, hypothalamus &
subthalamus
Pars ventralis; epithalamus &
metathalamus
MESENCEPHALON/ MID BRAIN
RHOMBONCEPHALON/ HIND BRAIN
Metencephalon
Pons & cerebellum
Myelencephalon
Medulla oblongata

Nervous System
MBBS (GMC)
PharmoHub Pakistan

Introduction
Brain
Stem
Telencephalon
Diencephalon
Cerebellum
Midbrain
Pons
Medulla oblongata
1.Divisions of nervous system
Central nervous system (CNS)
Peripheral nervous system (PNS):
Spinal cord
(1) Central nervous system (CNS)
Brain :

(2) Peripheral nervous system (PNS):
Cranial n. (12 pairs)
Spinal n. (31 pairs)
Visceral n. :
Introduction
Visceral sensory n.
Visceral motor n.:
Sympathetic part
Parasympathetic part

2. Basic terminology in nervous system:
(1) CNS:
1) Gray matter collection of
nerve cell bodies and their dendrites,
Introduction
the outer layer of gray matter
in cerebrum and cerebellum
A group of nerve cell bodies
which have the same shape
and function.
Cortex
Nucleus

2) White matter
collection of nerve fibers, white color during fresh condition
Introduction
a central core of white matter
beneath cortex of cerebrum
and cerebellum
a bundle of nerve fibers
which have the same
origin, termination, and
function
Medulla
Fasciculus ( tract ):

3) Reticular formation:
a field of intermingled grey and white matter , and with
larger or smaller groups of nerve cells occupying the meshes.
Introduction

Introduction
(2) PNS
1) Ganglion:
a collection of neuron cell
bodies outside the CNS
2) Nerve:
a bundle of nerve fibers held
together by connective tissue
sheath

The cerebrum is the
uppermost part of the brain. It
contains two hemispheres split
by a central fissure. The
cerebrum itself contains the
major lobes of the brain and is
responsible for receiving and
giving meaning to information
from the sense organs, as well
as controlling the body.

FUNCTION
 The largest part of the brain, the
cerebrum initiates and
coordinates movement and
regulates temperature. Other
areas of the cerebrum enable
speech, judgment, thinking and
reasoning, problem-solving,
emotions and learning. Other
functions relate to vision, hearing,
touch and other senses

LOBES OF CEREBRUM
 Each brain hemisphere (Cerebral cortex) has four
sections, called lobes: frontal, parietal,
temporal and occipital.
Lobes of the Brain and What They Control
 Frontal lobe.
 Parietal lobe.
 Occipital lobe.
 Temporal lobe.

Some Terminologies
 Ridges called Gyri (gyrus)
 Shallow grooves called Sulci (sulcus)
 Deeper grooves called Fissures

Central sulcus –
separates the
frontal and
parietal lobes
Parieto-
occipital
sulcus –
separates the
parietal and
occipital lobes
Lateral sulcus –
separates the
parietal and
temporal lobes

Enables sensation, communication,
memory, understanding, and
voluntary movements
Each hemisphere controls the
opposite (contralateral) side of the
body
Hemispheres are not functionally
equivalent (lateralization or
specialization of cortical functions)
No functional area acts alone -
conscious behavior involves the
entire cortex

Cerebral Cortex
Three kinds of functional areas:
Motor areas – control voluntary
movement
Sensory areas – conscious awareness
of sensation
Association areas – integrate diverse
information, communicate “associate”
with the motor cortex and sensory
association areas to analyze input

Blood supply of cerebrum
 The brain receives blood from two
sources: the internal carotid
arteries, which arise at the point in
the neck where the common carotid
arteries bifurcate, and the vertebral
arteries .The internal carotid arteries
branch to form two major cerebral
arteries, the anterior and middle
cerebral arteries

Internal carotid artery
 Ophthalmic
 Posterior commmunicating
 Choroidal artery
 Anterior cerebral artery
 Middle cerebral artery
nemonic : OP-CAM

Anterior cerebral artery
 Anterior communicating artery
 Cortical branches
 Central branches

Middle cerebral artery
 Cortical branches
 Central branches

Vertebral artery
 Meningeal branches
 Posterior spinal
 Anterior spinal
 Posterior inferior cerebellar
 Medullary arteries
NEMONIC : MPA-PM

Basilar artery
 The vertebral arteries of both sides
join to form Basilar artery.
 Pontine arteries
 Labryinthine arteries
 Anterior inferior cerebellar
 Superior cerebellar
 Posterior cerebral artery
nemonic : PP-LAS

 The terminal branches of the vertebral and internal carotid
arteries all anastomose to form a circular blood vessel,
called the Circle of Willis.
 There are three main (paired) constituents of the Circle of Willis:
 Anterior cerebral arteries – terminal branches of the internal
carotid arteries.
 Internal carotid arteries – located immediately proximal to the
origin of the middle cerebral arteries.
 Posterior cerebral arteries – terminal branches of the basilar
artery
 To complete the circle, two ‘connecting vessels’ are also present:
 Anterior communicating artery – connects the two anterior
cerebral arteries.
 Posterior communicating artery – branch of the internal
carotid, this artery connects the ICA to the posterior cerebral
artery

Brain and Cranial
Nerves
MBBS (GMC)
PharmoHub Pakistan

Terminology
 Hemispheres
 Gyrus (Gyri)
 Sulcus (Sulci)
 Longitudinal Fissure

Anatomy of the Brain
 Cerebrum
 Cerebellum
 Diencephalon
Thalamus
Hyothalamus
 Brain Stem
Midbrain
Pons
Medulla oblongat
a

Cerebrum
 Anatomy
Frontal lobe
Parietal lobe
Occipital lobe
Precentral gyrus
Postcentral gyrus
 Functions
Sensory cortex
Motor cortex
Emotion
Intellectual process
es
Auditory
Visual
Speech

CEREBELLUM
 The cerebellum (“little brain”) is a struct
ure that is located at the back of the
brain, underlying the occipital and tem
poral lobes of the cerebral cortex. The c
erebellum is important for making postu
ral adjustments in order to maintain bal
ance.

Cerebellum
 Anatomy
Hemispheres
 Functions
Compares intended
movement with wha
t is actually happeni
ng
Smooth, coordinate
d movements
Posture/balance

 Cerebellum is the largest part of the
hindbrain and weighs about 150 g. It
is enshrined in posterior cranial fossa
behind the pons and medulla oblongat
a and separated from these structures
by cavity of fourth ventricle. It is conn
ected to brainstem by three fibre tract
s known as cerebellar peduncles.

 There are three functional areas of the cerebell
um –
 Cerebrocerebellum (the largest division) - i
n planning movements and motor learnin
g
 Spinocerebellum - coordination of motor
movements and maintenance of muscular
tone.
 Vestibulocerebellum - to maintain the sta
bility of the head on the body

Brain Stem
 Anatomy
Medulla oblongata
Pons
Midbrain
 Functions
Medulla
 Relays motor and se
nsory information
 Regulates heartbeat,
breathing and blood
vessel dilation
Pons
 Control breathing

MEDULLA OBLONGATA
 Medulla oblongata is located at the b
ase of your brain, where the brain st
em connects the brain to your spinal c
ord. It plays an essential role in passin
g messages between your spinal cord
and brain. It's also essential for regula
ting your cardiovascular and respirator
y systems.

PONS…
 Pons is an essential part of the brain lo
cated above the medulla. It falls in the
category of the hindbrain. Pons is very
important part of brain for the regula
tion and control of a number of vit
al functions. It not only acts as a con
trol center, but also contains nuclei of
some important cranial nerves

 An important function of pons and me
dulla is the autonomous control of
the body's vital functions. For exa
mple the cardiovascular (medulla) cent
ers receive sensory inputs from the he
art and blood vessels (mechano-, baro
- and chemoreceptors) via the vagus n
erve and modulates heart rate and blo
od pressure

Protective Coverings
(Meninges)
 Dura mater
Dense connective tissue
 Arachnoid
Nonvascular connective tissue
 Pia mater
Highly vascular
Covers surface of the brain and spinal cord and inv
aginates along cortical surface to form perivascular
spaces

Cranial Nerves
 I: Olfactory
 II: Optic
 III:Oculomotor
 IV: Trochlear
 V: Trigeminal
 VI: Abducens
 VII: Facial
 VIII:Vestibulocochlear
Acoustic
 IX: Glossopharyngeal
 X: Vagus
 XI: Accessory
 XII: Hypoglossal
http://www.gwc.maricopa.edu/class/bio201/cn/cranial.htm

Mnemonic
 On
 Old
 Olympus’
 Tower
 Top
 A
 Fin
 And
 German
 Viewed
 A
 Hop

MNEMONIC
 OLFACTORY
 OPTIC
 OCULOMOTOR
 TROCHLEAR
 TRIGEMINAL
 ABDUCENS
 FACIAL
 VESTIBULOCOCHLEAR
 GLOSSOPHARYNGEAL
 VAGUS
 ACCESSORY
 HYPOGLOSSAL
 OH
 ONCE
 ONE
 TAKES
 THE
 ANATOMY
 FINAL
 VERY
 GOOD
 VACATION
 A-HEAD

SPINAL CORD and CSF
Dr.Ahmad Ali Qureshi
MBBS (GMC)
PharmoHub Pakistan

• The spinal cord is a tubular bundle of nervous tissue and supporting cells
that extends from the brainstem to the lumbar vertebrae. Together, the
spinal cord and the brain form the central nervous system.
• The spinal cord is a cylindrical structure, greyish-white in colour. It has a
relatively simple anatomical course:
• The spinal cord arises cranially as a continuation of the medulla
oblongata (part of the brainstem).
• It then travels inferiorly within the vertebral canal, surrounded by the
spinal meninges containing cerebrospinal fluid.
• At the L2 vertebral level the spinal cord tapers off, forming the conus
medullaris.
• As a result of the termination of the spinal cord at L2, it occupies around
two thirds of the vertebral canal. The spinal nerves that arise from the end
of the spinal cord are bundled together, forming a structure known as
the cauda equina.

• During the course of the spinal cord, there are two points of enlargement.
The cervical enlargement is located proximally, at the C4-T1 level. It
represents the origin of the brachial plexus. Between T11 and L1 is
the lumbar enlargement, representing the origin of the lumbar and sacral
plexi.
• The spinal cord is marked by two depressions on its surface. The anterior
median fissure is a deep groove extending the length of the anterior
surface of the spinal cord. On the posterior aspect there is a slightly
shallower depression – the posterior median sulcus.

Formation of the Spinal Nerves
• The spinal nerves are mixed nerves that originate from the spinal cord,
forming the peripheral nervous system.
• Each spinal nerve begins as an anterior (motor) and a posterior (sensory)
nerve root. These roots arise from the spinal cord, and unite at
the intervertebral foramina, forming a single spinal nerve.
• The spinal nerve then leaves the vertebral canal via the intervertebral
foramina, and then divides into two:
• Posterior rami – supplies nerve fibres to the synovial joints of the
vertebral column, deep muscles of the back, and the overlying skin.
• Anterior rami – supplies nerve fibres to much of the remaining area of the
body, both motor and sensory.
• The nerve roots L2-S5 arise from the distal end of the spinal cord, forming
a bundle of nerves known as the cauda equina.

BLOOD SUPPLY OF SPINAL CORD
• The main blood supply to the spinal cord is via the single
anterior spinal artery (ASA) and the two posterior spinal
arteries (PSA). The anterior spinal artery is formed by the
vertebral arteries which originate from the first part of the
subclavian artery.
• Venous drainage is via three anterior and three
posterior spinal veins. These veins are valveless, and form an
anastamosing network along the surface of the SPINE.

Cerebrospinal fluid and
VenTriCles

Substance CSF Plasma
Na+ 147 150
K+ 2.9 4.6
HCO3- 25 24.8
PCO2 50 39.5
pH 7.33 7.4
Osmolality
Glucose
289
64
289
100

It is formed by the tight junctions between capillary endothelial
cells of the brain and between epithelial cells in the choroid
plexus. This effectively prevents proteins from entering the brain
in adults and slow the penetration of smaller molecules.
Mechanisms of transport:
- Bulk flow.
- Carrier mediated transfer
- Vesicular transport.

Penetration of substances into the brain
• Molecules pass easily:H2O, CO2, O2, lipid-soluble free forms of
steroid hormones.
• Molecules not pass: proteins, polypeptides.
• Slow penetration: H+, HCO3-
• Glucose : its passive penetration is slow, but is transported
across brain capillaries by GLUT1

Functions of BBB
• Maintanins the constancy of the environment of the neurons in
the CNS.
• Protection of the brain from endogenous and exogenous toxins.
• Prevent escape of the neurotransmitters into the general
circulation.

Clinical implications
• Some drugs penetrate BBB with difficulty e.g. antibiotics and
dopamine.
• BBB breaks down in areas of infection, injury, tumors, sudden
increase in blood pressure, and I.V injection of hypertonic fluids.
• Injection of radiolabeled materials help diagnose tumors as BBB
is broken down at tumor site because of increased vascularity
by abnormal vessels.

ANATOMY OF THE EAR
MBBS (GMC)
PharmoHub Pakistan

The External Ear
• Consists of:
– Auricle (pinna)
• Made of elastic
cartilage
• Helix (rim)
• Lobule (ear lobe)
– External auditory
canal
• Lies within temporal
bone & connects to
ear drum (tympanic
memb)
• Contains ceruminous
glands which secrete
ear wax
– Tympanic membrane
• Epithelial & simple
cuboidal
• Changes acoustic
energy into
mechanical energy
• Perforated eardrum =
tear

The Middle Ear
• Auditory Ossicles (smallest
bones in body)
– Malleus
• Attaches to ear drum
• Articulates with incus
– Incus
• Articulates with stapes
– Stapes (stirrup)
• Footplate of stapes fits into
oval window
• Opening to Eustachian tube

Protection by Two Tiny Muscles
• Tensor Tympani
– Attaches to Malleus to
increase tension on ear
drum & prevent damage to
inner ear.
• Stapedius
– Smallest skeletal muscle
– Dampens large vibrations of
stapes to protect oval
window.
stapedius

• Auditory Tube
(Eustachian tube)
– Is a route for pathogens
to travel from nose and
throat to ear causing
Otitis Media
– During swallowing and
yawning it opens to equal
pressure in middle ear. Normal Ear Drum Inflamed Ear Drum

The Inner Ear (Labyrinth)
• Bony labyrinth
– Contains perilymph
– Semicircular canals
• Anterior, posterior, and
lateral
• Lie right angles to each
other
– Vestibule
• Oval portion
– Cochlea
• Looks like a snail
• Converts mechanical energy
into electrical energy
• Membranous labyrinth
– Contains endolymph, high
in K+ ions

The Cochlea
• Divided into 3 channels
– Cochlear duct (scala media)
• Contains the Organ of Corti
– Scala vestibuli
• Ends at the oval window
– Scala tympani
• Ends at the round window

Organ of Corti
• The end organ of
hearing
– Contains stereocilia &
receptor hair cells
– Tectorial and Basilar
Membranes
– Cochlear fluids
– Fluid movement causes
deflection of nerve
endings
– Nerve impulses
(electrical energy) are
generated and sent to
the brain

Summary of How We Hear
Acoustic energy, in the form of sound
waves, is channeled into the ear canal by
the pinna. Sound waves hit the
tympanic membrane and cause it to
vibrate, like a drum, changing it into
mechanical energy. The malleus, which
is attached to the tympanic membrane,
starts the ossicles into motion. The
stapes moves in and out of the oval
window of the cochlea creating a fluid
motion, or hydraulic energy. The fluid
movement causes membranes in the
Organ of Corti to shear against the hair
cells. This creates an electrical signal
which is sent up the Auditory Nerve
(cochlear nerve) to the brain. The brain
interprets it as sound!

MBBS (GMC)
PharmoHub Pakistan

Lateral rectus – 6th cranial nerve
Superior Oblique – 4th cranial berve
Medial rectus
Superior rectus
Inferior rectus
Inferior oblique
Nemonic ; LR6SO4R3
3rd Cranial
nerve

Dr AhmAD Ali
Qureshi
(mBBs,GmC)
PharmoHub Pakistan

Lecture on Anatomy of the Heart ( drnnamanisamuel@gmail.com)
Kindly recite Drood shareef

 Lies within the pericardium in middle mediastinum
 Behind the body of sternum and the 2nd to 6th costal
cartilages
 In front of the 5th to 8th thoracic vertebrae
 A third of it lies to the right of median plane and 2/3 to
the left
 Anterior to the vertebral column, posterior to the sternum

 A hollow muscular organ, pyramidal in shape , somewhat
larger than a closed fist; consists of four chambers (right and
left atria, right and left ventricles)
 Cardiac Apex is formed by left ventricle and is directed
downwards and forwards to the left. It lies at the level of the
fifth left intercostal space, 1~2cm medial to the left
midclavicular line (9cm from the midline)
EXTERNAL CHARACTERISTICS

 The apex beat 【point of maximum impulse (PMI)】,
is the furthermost point outwards (laterally) and
downwards (inferiorly) from the sternum at which the
cardiac impulse can be felt.
 Lateral and/or inferior displacement of the apex beat
usually indicates enlargement of the heart, called
cardiomegaly
 Approximately the size of your fist
 Wt. = 250-300 grams
 Cardiac base is formed by the left atrium and to a small
extent by the right atrium. It faces backward, upward
and to the right
EXTERNAL CHARACTERISTICS

Two surfaces
 Sternocostal surface is formed mainly by the right atrium
and right ventricle, and a lesser portion of its left is formed by
the left auricle and ventricle. It is directed forwards and
upwards
 Diaphragmatic surface is formed by the ventricles－
chiefly the left ventricle, directed backwards and downwards,
and rests upon the central tendon of the diaphragm
Three borders
 Right border－vertical, is formed entirely by right atrium
 Left border－round, is mainly formed by the left ventricle
and partly by the left auricle
 Inferior border－horizontal, is formed by the right ventricle
and cardiac apex

Four grooves
 Coronary sulcus (circular sulcus) which marks the division
between atria and ventricles, contains the trunks of the coronary
vessels and completely encircles the heart
 Interatrial groove －separates the two atria and is hidden by
pulmonary trunk and aorta in front
 Interventricular grooves － anterior and posterior, mark the
division between ventricles (which separates the RV from the LV),
the two grooves extend from the base of the ventricular portion to a
notch called: the cardiac apical incisure

 Pericardium – a double-walled sac around the heart
 Composed of:
 A superficial fibrous pericardium
 A deep two-layer serous pericardium
 The parietal layer lines the internal surface of the fibrous
pericardium
 The visceral layer or epicardium lines the surface of the heart
 They are separated by the fluid-filled pericardial cavity called the
pericardial cavity
 Protects and anchors the heart
 Prevents overfilling of the heart with blood
 Allows for the heart to work in a relatively friction-free environment
COVERING OF THE HEART

Interatrial septum
 Located between right and left atria
 Contains fossa ovalis
Interventricular septum Located between right and left ventricles
 upper membranous part
 thick lower muscular part

 Epicardium – visceral pericardium
 Myocardium – cardiac muscle layer
forming the bulk of the heart
 Endocardium – endothelial layer of the
inner myocardial surface
LAYERS OF THE HEART WALL

XRAY
NORMAL LVH（ Left ventricular hypertrophy ）

 Atria - receiving chambers of the heart
 Receive venous blood returning to heart
 Separated by an interatrial septum (wall)
 Foramen ovale - opening in interatrial septum in fetus
 Fossa ovalis - remnant of foramen ovale
 Each atrium has a protruding auricle
 Pectinate muscles mark atrial walls
 Pump blood into ventricles
 Blood enters right atria from superior and inferior venae cavae and
coronary sinus
 Blood enters left atria from pulmonary veins
ATRIA OF THE HEART

Left auricle－projecting to the
right, pectinate muscles in wall
Four inlets－four orifices of
pulmonary veins open through the
posterior wall
One outlet－left atrioventricular
orifice, blood leaves through left
atrioventricular orifice to left
ventricle

 Ventricles are the discharging chambers of the heart
 Papillary muscles and trabeculae carneae muscles mark
ventricular walls
 Separated by an interventricular septum
 Contains components of the conduction system
 Right ventricle pumps blood into the pulmonary trunk
 Left ventricle pumps blood into the aorta
 Thicker myocardium due to greater work load
 Pulmonary circulation supplied by right ventricle is a much low pressure
system requiring less energy output by ventricle
 Systemic circulation supplied by left ventricle is a higher pressure system
and thus requires more forceful contractions
VENTRICLE OF THE HEART

It’s wall is three times thicker
than that of right ventricle
One inlet－left atrioventricular
orifice
One outlet－aortic orifice
Two parts－divided by anterior
cusps of mitral valve
Inflow tract－rough walls
Outflow tract – aortic
vestibule smooth area
leading to aortic orifice
Left ventricle

Interatrial septum
 Located between right and left atria
 Contains fossa ovalis
Interventricular septum Located between right and left ventricles
 upper membranous part
 thick lower muscular part
Fibrous skeleton
 Fibrous rings that surround the atrioventricular, pulmonary, and
aortic orifices
 Left and right fibrous trigons
SEPTUMS/FIBROUS SKELETON

 Heart valves ensure unidirectional blood flow through the heart
 Composed of an endocardium with a connective tissue core
 Two major types
 Atrioventricular valves
 Semilunar valves
 Atrioventricular (AV) valves lie between the atria and the
ventricles
 R-AV valve = tricuspid valve
 L-AV valve = bicuspid or mitral valve
 AV valves prevent backflow of blood into the atria when ventricles
contract
 Chordae tendineae anchor AV valves to papillary muscles of
ventricle wall
 Prevent prolapse of valve back into atrium
HEART VALVES

 Semilunar valves prevent backflow of blood into the ventricles
 Have no chordae tendinae attachments
 Aortic semilunar valve lies between the left ventricle and the aorta
 Pulmonary semilunar valve lies between the right ventricle and
pulmonary trunk
 Heart sounds (“lub-dup”) due to valves closing
 “Lub” - closing of atrioventricular valves
 “Dub”- closing of semilunar valves
SEMILUNAR HEART VALVES

Tricuspid valve
 Guards right atrioventricular orifice
 Three triangular cusps: anterior, posterior and septal, the base
of cusps are attached to fibrous ring surrounding the
atrioventricular orifice
 Chordae tendineae －fine, white, connective tissue cords,
attach margin of cusps to papillary muscles
Mitral valve
Guards left atrioventricular orifice
 Two triangular cusps－anterior and posterior with Similar
structures to those of right

Valve of pulmonary trunk
 Guards the orifice of pulmonary trunk
 Has three semilunar cusps – each with free border

 Cardiac muscle tissue has intrinsic ability to:
 Generate and conduct impulses
 Signal these cells to contract rhythmically
 Conducting system
 A series of specialized cardiac muscle cells
 Sinoatrial (SA) node sets the inherent rate of
contraction
CONDUCTING SYSTEM OF THE
HEART

CONDUCTING SYSTEM OF THE
HEART

 Heart rate is altered by external controls
 Nerves to the heart include:
 Visceral sensory fibers
 Parasympathetic branches of the vagus
nerve
 Sympathetic fibers – from cervical and
upper thoracic chain ganglia
INNERVATION

Sinuatrial node (SA node)
 Called the pacemaker cell (P cell)
 Located at the junction of right atrium and superior vena cava,
upper part of the sulcus terminalis, under the epicardium

Atrioventricular node (AV node)
 Located in the lower part of interatrial septum just above the
orifice of coronary sinus, under the endocardium
 Lower part related to membranous part of interventricular septum
Atrioventricular bundle (AV bundle)
 Passes forward through right fibrous trigon to reach inferior border
of membranous part
 Divides into right and left branches at upper border of muscular
part of interventricular septum

 Vessels returning blood to the heart include:
 Superior and inferior venae cavae
 Open into the right atrium
 Return deoxygenated blood from body cells
 Coronary sinus
 Opens into the right atrium
 Returns deoxygenated blood from heart muscle (coronary
veins)
 Right and left pulmonary veins
 Open into the left atrium
 Return oxygenated blood from lungs
MAJOR VESSELS OF THE HEART

 Vessels conveying blood away from the heart include:
 Pulmonary trunk
 Carries deoxygenated blood from right ventricle to lungs
 Splits into right and left pulmonary arteries
 Ascending aorta
 Carries oxygenated blood away from left atrium to body
organs
 Three major branches
 Brachiocephalic
 Left common carotid,
 Left subclavian artery
MAJOR VESSELS OF THE HEART

PATHWAY OF BLOOD THROUGH THE
HEART

 Coronary artery disease
 Atherosclerosis – fatty deposits
 Arteriosclerosis - hardening of the arteries
 Angina pectoris – chest pain
 Myocardial infarction – blocked coronary artery
 Silent ischemia – no pain or warning
 Fibrillation - irregular heart beat; may occur in either
atria or ventricles
DISORDERS OF THE HEART

Lecture on Anatomy of the Heart ( drnnamanisamuel@gmail.com)

BLOOD VESSELS
MBBS (GMC)

Blood Vessels
Functions
• Distribution of blood
• Exchange of materials withtissues
• Return of blood to the heart
Closed circulatory system
1. Arteries
2. Arterioles
3. Capillaries
4. Venules
5. Veins
6. 3 tunics
7. Lumen
Generalized Structure of Blood Vessels
1. Arteries and veins are composed of three tunics (Tunica
interna, Tunica media, and Tunica externa)
2. Lumen - central blood-containing space surrounded by tunics

3. Capillaries are composed of endothelium with sparse basal
lamina
The Anatomy of Blood vessel
Layers:
1. Tunica interna(intima):
• Endothelial layer that lines the lumen of all vessels.
• In vessels larger than 1 mm, a subendothelial connective
tissue basement membrane is present.
2. Tunica media:
• Smooth muscle and elastic fiber layer, regulated by
sympathetic nervous system.
• Controls vasoconstriction/vasodilation of vessels
3. Tunica externa (adventitia):
• Collagen fibers that protect and reinforce vessels
• Larger vessels contain vasa vasorum
General Structure

Arteries: (carry blood away from heart)
• Strong & Elastic
• Conduct blood to Capillaries
• Sphincters
Capillaries: (exchange materials with cells, tissue)
Veins: (return blood to heart)
• Valves

Make up of Blood Vessels:(Arteries and
Arterioles)
• Endothelium
• Elastic tissues
1.rebounds

2. evensflow
• Smooth muscles
• Fibrous Tissue
1.Tough
2.Resists stretch

Types of Blood vessels:
1. Elastic Arteries:
• Thick-walled arteries near the heart, the aorta and its
major branches.
• Large lumen allows low-resistance conduction of blood.
• Contain lots of elastin in all three tunics
• Walls stretch and recoil to propel blood
• Withstand and regulate large blood pressure fluctuations
• Allow blood to flow fairly continuously through the body
2. Muscular (Distributing) Arteries:
• distal to elastic arteries deliver blood to body
organs
• Have thick tunica media with
muscle and less elastic tissue
• Active in vasoconstriction
3. Arterioles:
more smooth

• smallest arteries; lead to capillary beds
• Control flow into capillary beds via vasodilation
and constriction
Venous System: (veins)

• Veins have much lower blood pressure and thinner
walls than arteries
• To return blood to the heart, veins have special
adaptations:
1.Large-diameter lumens, which offer little
resistance to flow
2. Valves (resembling semilunar heart valves),
which prevent backflow of blood
• Venous sinuses - specialized, flattened veins
with extremely thin walls (e.g., coronary
sinus of the heart and Dural sinuses of the
brain)
Make up of Blood Vessels: Veins and
Venules (Contrasted to Arteries)
• Thinner walls
• Larger diameter
• Closer to skin
• Less muscle

• Less elastic
Arterioles (Diameter of 0.3 mm or less)
smallest arteries, lead to capillary beds
close to capillaries - single layer of muscle
spiralling around the endothelial lining
regulates blood flow to Capillaries.
Venous System: Venules

These are formed when capillary beds unite
• Allow fluids and WBCS to pass from the
bloodstream to Tissue
Post Capillary Venules:
smallest venules composed of endothelium
and a few pericytes
Large venules:
have one or two layers of smooth muscle
(tunica media)
Venous System: Veins
• Veins are formed when venules
converge
• Composed of three tunics, with a thin
tunica media and a thick tunica

externa consisting of collagen fibers
and elastic networks
• Capacitance vessels (blood reservoirs)
that contain 65% of the blood supply
Vascular Anastomoses
• Merging blood vessel are more
common in veins than arteries
• Arterial anastomoses provide
alternate pathways (collateral
channels) for blood to reach a given
region
• If one branch is blocked, the
collateral channel can supply the
area with adequate blood supply

• Thoroughfare channels are
examples of arteriovenous
anastomoses
Capillaries
• A capillary wall is very thin and
composed of (endothelium only)
• Single layer of cells as it does not
have ability to withstand high internal
pressure.
• A capillary wall is often highly
permeable, partly because it’s very
thin and partly because of holes in
and between cells in some capillaries
(particularly those with high demand
of exchange e.g., endocrine glands)

Capillaries are the smallest blood
vessels
• walls consisting of a thin tunica
interna, one cell thick
• allow only a single RBC to pass at a
time
• pericytes on the outer surface their
stabilize their walls
There are three structural types of
capillaries: continuous, fenestrated,
and sinusoids
Continuous Capillaries
Continuous capillaries are abundant
in skin and muscles and have:

• endothelial cells that provide an
uninterrupted lining
• adjacent cells that are held together
with tight junctions
• intercellular clefts of unjoined
membranes that allow the passage
of fluids
Continuous capillaries of the brain:
• have tight junctions completely
around the endothelium
• constitute the blood-brain barrier
Fenestrated Capillaries
found wherever active capillary
absorption of filtrate formation occurs (,

small intestines endocrine glands, and
kidney's)
Characterized by:
• An endothelium riddled with pores
(fenestrations)
• Greater permeability to solutes and
ions than other capillaries
Sinusoids
• Highly modified, leaky, fenestrated
capillaries with large lumens
• Found in the liver, bone marrow,
lymphoid tissue and in some
endocrine organs

• Allow large molecules (proteins and
blood cells) to pass between the
blood and surrounding tissue
• Blood flows sluggishly, allowing for
modification in various ways
Capillary Beds
A microcirculation of interwoven
networks of capillaries
Consisting of:
• Vascular shunts- metarteriole-
thoroughfare channel connecting an
arteriole directly with a post capillary
venule
• True capillaries - 10 to 100 per
capillary bed, capillaries branch off

the metarteriole and return to the
thoroughfare channel at the distal
end of the bed
Precapillary sphincter
• Cuff of smooth muscle that surrounds
each true capillary

• Regulates blood flow into the
capillary
Blood flow is regulated by vasomotor
nerves and local chemical conditions, so
it can either bypass or flood the capillary
bed
Blood Flow in Capillaries
Blood moves slowly in capillaries
because there are more capillaries than
arterioles.
This allows time for substances to be
exchanged between the blood and
tissues.
(by#148)

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Human Anatomy Complete Notes