Anatomy

The Medical LabTechnician572
UNIT
Introduction to Human
Anatomy
1
Structure
1.1Introduction
1.2 Someimportant definitions
1.3 Severalterms used in anatomyto describe.
1.4Terms to describe movements occuring at various joints.
1.5 Different anatomicalsystemofhumanbody.
Summary
Learning Objectives
• Student should be able to know the meaning and historicalback
ground ofAnatomy.
• Student should be able to know the meanings ofdifferent terms and
definitions ofanatomy.
• Student should have anidea ofdifferent anatomicalsystems of
human body.
1.1 Introduction
Anatomy is the studyofstructure of human body. Studyof anatomy
helps inunderstandingthefunctions ofbody. Herophilus(335-280BC)bornin
ChalcedoninAsiaMinor(nowKadiköy,Turkey),andlater movedto Alexandria

Paper - III Anatomy & Physiology 573
is called the ‘Farher of anatomy’. Andreas Vesalius, a Flemish physician is
referredto asthe‘Fatherof modernhumananatomy’. Different aspectsincluded
inanatomyareHistology, Osteology, Myology,Arthrologyand Neurologyetc.
Histologyis studyoftissues. Osteologyis studyofbones. Myologyis studyof
muscles.Arthrologyis studyofJoints. Neurologyis studyofnervesandnervous
system.
Fig. 1.1AndreasVesalius, Latinized form of Andries van Wesel ( 1514 – 1564)
“Father ofmodern humananatomy”
1.2 Some Important Definitions
Cell: Cell is the tiniest particle of body. It is the basic functional and
structuralunit ofbody.
Tissue: Tissue isa group of cells ofsimilarityinstructure,functionand
origin.
Organ:Organ is a group of different kinds oftissues for performing
specificfunctions.
System:System is collection of different organs of body to work
collectivelyto conduct some kinds offunctions.
Ex: Respiratorysystem, Digestive system, etc.
Organism : Organismconsists ofdifferent systems.
1.3 Several Terms used in Anatomy to indicate Anatomical
Positions
Some ofthe terms are-
1. Superior: Nearer to head.
2. Inferior:Lower or below

3.Anterior orventral: Front
4. Posterior or dorsal: Back
5. Proximal: Nearer
6. Distal:Away
7. Superficial: Nearer to the skin surface.
8. Deep: Deeper fromskin surface.
9. Medial: Nearer to midline.
10. Lateral:Awayfrommidline.
Median lineor sagittalline: It is imaginaryplane dividing the bodyinto
two halves.
Fig. 1.2Anatomical Positions
Horizontalsection: It divides bodyinto superior and inferior portions.
Sagittalsection: It divides bodyinto right and left portions.Coronalsection: It
divides the bodyinto anterior and posterior portions.
1.4 Terms to describe movements occuring at Various
Joints
1. Flexion:Flexionisthe movement wheresimilarsurfaces comenearer
to eachother reducing the anglebetweenthem.ex: Bending offore arm
near elbow.
2. Extension: Itis the movement causingsimilar surfacesto go apart. It

is opposite to flexion. ex : Straightening ofbent fore arm.
3. Adduction: It is the movement bringing the limbtowards mid line.
4.Abduction: It is the movement taking the limbawayfromthe mid
line.
5. Rotation: It is the movement around centralaxis involving 3600
.
6. Medial rotation : It is rotation towards medialdirection.
7. Lateral rotation: Rotationtowards lateraldirection iscalled lateral
direction.
8. Circumduction: It isthe movement involvingflexion, abduction,
extensionand adductionoccuring insequence.
1.5 DifferentAnatomical Systems of Human Body
Different anatomicalsystems ofhumanbodyand their parts inbriefare-
1. Skeletal system
Total206 bones forming the human skeleton canbe divided into-
(1) Bones ofAxialskeleton (2)Bones ofappendicular skeleton
(1) Bones ofAxialskeleton are divided into- (i) Bones of skull&
(ii) Bones oftrunk.
(i) Bones ofskull: a. Bones ofcraniumb. Bones offace
(ii) Bones oftrunk:: a. Sternumb. Ribs c. Vertebralcolumn
(2) Bonesofappendicular skeleton:
a. Bones ofupper limbs b. Bones oflower limbs
2. Muscular system
The muscular systemis the body's largest system, normallycomprising
about 40 percent ofbodyweight.
Muscles are three types. 1. Skeletal muscles 2. Cardiac muscle 3.
Smoothmuscles
3. Respiratory system
1. Nose 2. Pharynx3. Larynx 4. Trachea Theyleadto the lungs.
5. Bronchi 6. Bronchioles 7. Alveolar ducts 8. Alveoli

Fig1.3Outer partsofbody male & female
4. Digestive System and Hepato Biliary System
Various parts of the Digestive tract-
1. Mouth 2. Pharynx 3. Oesophagus 4. Stomach 5. Small
intestine 6. Large intestine 7. Rectum 8. Anus
Accessory organs of the digestive tract -
1. Teeth 2. Three pairs ofsalivaryglands 3. Liver and biliarysystem
4. Pancreas
5. Cardio vascular System
Cardiovascular systemconsists of Heart and Vascular system. There
are two types ofblood vessels mainly. Theyare arteries and veins.
6. Lymphatic System
Lymphaticsystemisaclosedsystemconsistingof1)Lymphaticcapillaries
2)Lymphatic vessels 3) Lymph nodes and 4) Lymphducts.

7. Nervous System
Nervous System
Peripheralnervous system(PNS) Central nervoussystem( CNS)
Brain Spinal cord
Autonomic nervous system(ANS) Somatic nervous system.
Sympathetic nervous system ( SNS) Para sympathetic nervous system( PSNS).
8. Excretory system
Excretorysystemconsistsof channelsofexcretion.Theyare-
1. Urinarysystemconsisting of- Kidneys( 2), Ureters (2), Urinary
bladder& Urethra
2. Skin 3. Liver 4. Lungs ( 2) 5. Digestive tract 6. Salivary
glands (3 pairs)
9. Endocrine System
Endocrine glands of human bodyare- (1) Hypothalamus
(2) Pituitarygland (Master gland) (3) Thyroid gland
(4) Parathyroid gland (5) Adrenal glands
(6) Pancreas (7) Testes
(8) Ovaries (9) Placenta
(10) Thymus & (11) Pineal body
10. Reproductive System
Male reproductive system:
Parts of male reproductive system are- Testes, Epididymis, Vas
deferens, Seminalvesicles, Ejaculatoryducts, Prostate gland, Bulbo urethral
glands& Penis.
Female reproductive system:

Fromoutside inwards it contains the parts as follows :
- Vagina - Uterus - Fallopian tubes - Ovaries
11. Sense Organs
Sense organs of human body are eyes( 2), Ears (2), Nose, Tongue&
Skin.
Conclusion
Anatomy is thescience ofstudyofstructure ofhumanbody. It helps in
understanding thefunctions ofvarious systemsofhuman body.
Summary
Anatomyis the science dealing with structure ofbody. Subject matter
ofanatomyincludesHistology, Osteology, Myology,Arthrology, Neurologyetc.
Various termsdescribing the human bodyare - Median line, medial, lateralsu-
perior, inferior,anterior, posterior, proximal, distal, superficial, deep etc. Terms
describing the movements occuring at various joints ofbodyare- Flexion, ex-
tension, adduction, abduction, rotation, medialrotation,lateralrotation, circum-
ductionetc.
Different anatomicalsystems ofhumanbodyare-
1. Skeletal system 2. Muscular system
3. Respiratorysystem 4. DigestiveSystemandHepato BiliarySystem
5. Cardio vascular System6. Lymphatic System
7. Nervous System 8. Excretorysystem 9. Endocrine System
10. Reproductive System11. Sense Organs
Model Questions
Short Answer Type Questions
1. Defineanatomyand mention various subjects which enrich
Anatomy.
2. Write the definitions of a) Histology b) Osteology.
3. What are a) Myology b)Arthrology c) Neurology ?
4. Explainthe terms -Medianline, medialand lateral.
5. Define theterms superior and inferior.

6. Write the definitions of a)Anterior b) Posterior.
7. Give the definitions of a) Proximal b) Distal.
8. Explainthe terms - Superficialand deep.
9. Define the movements a) Flexion b) Extension.
10. Writethe definitions ofAdductionandAbduction.
11. Explainthe terms a) Rotation b) Circumduction.
12. Define the temrs a) Medialrotation b) Lateralrotation.
Long Answer Type Questions
1. DefineAnatomyand write theintroductionofAnatomy.
2. Explain in briefabout different anatomicalsystems ofhuman body.

UNIT
Cell Tissue
2
Structure
2.1 Cell
2.2Tissue -Classificationinbrief.
2.3 Summary
Learning Objectives
• Student should know the structure and properties ofa cell.
• Student should know various typesoftissues.
2.1 Cell
2.1.1 Definition
Cellisthebasicstructuralandfunctionalunitoflivingmatter.Itisthesmallest
unit oflife. It is capableofcarrying life processesindependently. Someorganisms
suchas bacteria are unicellular.
2.1.2 Structure and Properties
2.1.2.1 Structure of Cell
There are two types ofcells inbody. Theyare 1) Somatic cells 2) Gonadal
cells.
Somatic cells are diverse cells whichmake up somatic structure of body.

Gonadalcells aregametes whichcan unite to formnew individual.
Fig 2.1 Structure of a Cell
Cells vary in size and shape. Most of the cells contain similar type of
intracellularcomponents.Averagesize ofmammaliancellis 10-2 mmindiameter.
Everycellcomprises following parts.
1. Cellwall(cellmembrane)
2. Protoplasm, consisting ofCytoplasmand Nucleus
Cell Wall
It isalso called as plamsalemmaor plasma membrane orcellmembrane. It
istheouter protectivelayerofcell. It isolatescellfromneighbouringenvironment.
It cannot beseenbylight microscope. It can be seenbyelectron microscope. It
is about 80 A0 thick. It has trilaminar structure of phospholipid bilayer
sandwitchedbetweentwo denselystainedproteinlayers. Phospholipidmolecules
have twoparts.Theyare1)Head (Phosphate)&2)Tail(Fattyacid)outer surface
of cell wall contains pinocytotic vesicles. Inner surface is continuous with
endoplasmic reticulum (ER). Functions ofcellwallare1)Transport ofmaterials
(main function) 2) Protection 3) Receptionofexternalstimuli. 4) Ingestion of
nutrients 5)Excretionofwaste productsofcellular metabolism.
Cytoplasm
Cytoplasm is the mass of living matter between cell walland nucleus. It
containsstoredfoods, secretiongranules, pigmentsandcrystals.These arecalled

cytoplasmic inclusions. Stored foods are carbohydrates, fats, proteins, minerals
andvitamins. Pigmentsaretwo types-endogenousandexogenous. Endogenous
pigmentsare haemoglobinand melanin. Exogenouspigmentsare carotene from
vegetables, dusts(carbon)andminerals (silver, leadetc.)Cytoplasmic organelles
are- Endoplasmic reticulum, Golgi apparatus, Mitochondria, Lysosomes,
Ribosomes, Centrosomes etc.
Endoplasmic reticulum
Endoplasmic reticulum is system that continues with infoldings of cell
membrane and interlaces with the interior of cell. There are two types of
endoplasmic reticulum- Smooth ER&Rough ER Smooth ER is network of
smoothtubules.FunctionsofsmoothERare metabolismandsynthesisofsteroids
andglycogen.RoughERconsistsofribosomes. It isprominentinAdrenalcortex,
liver and striated muscle. Functions ofroughER are 1) Proteinsynthesis & 2)
Translationoflanguageofnucleic acids.
Golgi apparatus
It isshapedlikenetworkofthreads. Its functionsare 1)Synthesisofvarious
secretions& 2) Storage ofenzymes, ascorbicacid and some other substances.
Mitochondria
They are granular, filamentous or rod shaped solid bodies. Theyvary in
sizefrom0.5 to 5microns.Theyaresurroundedbytrilaminar doublemembrane.
Inner one remains folded to form partitions called cristae mitochondriales.
Intramitochondrial space contains fluid called matrix. Number and size of
mitochondria ofa cellare determined byenergyrequirements ofcell. Cells of
liver, kidneyand heart possess largeamount ofmitochondria.
Functions ofmitochondria are 1) Theyare called power houses of cells.
Theysupply95% ofcell’s energyrequirement. In presence ofoxygen, Kreb’s
cycle runs in mitochondria with thehelp ofrespiratoryenzymes- flavoprotein
enzymes and cytochrome. These enzymes help in oxidative phosphorylation
Theyprovide site for formation ofATP. & 2) Synthesis ofRNAand DNA.
Lysosomes
They are digestive organs of cells. They are also called suicide bags of
cells. Theyare digestive organelles ofcells. Theycontain powerfulhydrolytic
enzymes. Lysosomesareabsent inRBC.Functionsoflysosomesare 1)Breaking
down ofparticles taken in to celland digestion. 2)Autolysis 3) Phagocytosis
4) Killing ofcells (planned way) 5) Celldivision etc.

Ribosomes
Theyare scattered through out cytoplasmsingly or as groups. Theyare
ribonucleoproteininnature. Their functionisproteinsynthesis.
Centrosome
Centrosome contains centrioles. Centrioles controlpolarisationofspindle
fibres. Centriole is closely related to spindle formation during cell division
(Mitosis).
Plasmosin
Plasmosin isconstant constituent ofcytoplasm. Theyform
- Tonofibrils inepithelial cells, myofibrils in muscles and neurofibrils in
nerves.
Theyconsist oflong proteinmoleculesrichindeoxy-ribonucleoprotein.
Vacuoles
Theyare also cytoplasmic organelles. Theyare found covered byfat on
staining withdiluteneutralred solution.
Nissl bodies
Theyare found in nerve cells.
Secretory granules
They store secretoryproducts of celland are found in- Golgi apparatus
and E.R.
Nucleus
It isthekeystructureoflivingcell.Nucleusiscoveredbynuclearmembrane.
Nucleus consists ofchromatinand nucleolus. Chromatinis dense chromosomal
network. There is usuallysimple nucleolus or 2-5 nucleoliina cell. Nucleolus
contains nucleolemma. Nuclearmaterialdiffers fromcytoplasminseveralways.
Chromosomes seen in interphase nucleus are densely stained portions of
chromosomes. Chromatincontains different genes whichdetermine heredityof
cell.
Chromosomes
Chromosomes are present as individualbodies in interphase as wellas in
mitosis. Predominant component inchromosome is DNA. Genesare located in
chromosome. Theyarediscrete units oftransmissionofhereditarycharacters.

Infemale,2X chromosomesand inmales 1X and 1Ychromosomes are present.
2.1.2.2 Properties
Properties ofcellin unicellular organisms like amoeba are -
(a) Irritability (b)Conductivity
(c) Contractility (d)Absorption
(e) Excretion (f) Growthand reproduction
(g)Motility (h) Secretion
2.2 Tissue - Classification in Brief
2.2.1 Tissue
Tissue is defined as group ofcells of similarity in structure,function and
genesis.
2.2.2 Classification
Human bodycontainsfollowing types oftissues.
1) Epithelialtissue2) Connective tissue3) Muscular tissue& 4) Nervous
tissue
2.2.2.1 Epithelial tissue
Epithelial tissue gives covering to other tissues by forming epithelial
membrane. Epithelialmembrane rests upon lamina propria. Laminapropria is
loose vascular connective tissue, which supplies requirements to epithelial
membrane. Cellsofepithelialtissuelieclosetogethercementedbyamucoprotein
containing hyaluronic acidand calciumsalts.
Functions ofepithelialtissue are -
1. Protection to underlying surfaces 2. Providing surface for absorption
3. Secretoryactivity 4. Excretion
Types ofEpithelialtissue: Epithelialtissue ismajorlyclassified into
1. Simple epithelium- consisting ofsinglelayer ofcells
2. Compound epithelium- consisting ofmultiple layers ofcells.
Simple epithelium:Different types ofsimpleepithelialtissues are
(a) Squamous or pavement epithelium-consisting ofsingle layerofflat

cells.
(b) Cuboidalepithelium-consistingofsingle layer ofcuboidalcells ofsame
dimensions.
(c) Columnarepithelium-consistingofsinglelayerofcellswhicharelengthier
inheight thanbreadth.
(d) Ciliatedcolumnarand cuboidalepithelium-columnarand cuboidalcells
containingcilia.
(e) Glandular epithelium- lining the alveoliandducts ofglands.
Squamousorpavement epithelium:
It isfound in alveolioflungs, serous membranes like peritoneum, pleura,
nephrons, inner liningofheart etc.
Functions:1. Dialysis2. Passage ofliquids 3. Protection
Cuboidalepithelium: Theyarefoundininnerpartsofthyroidgland, salivary
glands, digestiveglands etc.
Functions 1. Protection 2. Secretion3. Storage etc.
Columnar epithelium: It issupported bybasement membrane. It is found
instomach,smallintestine,largeintestine,alveoli,ductsofglandsetc.Inalimentary
canaland nephron, it isbrushbordered.Goblet cellsareanothertypeofcolumnar
epitheliumfoundinlarge intestine mainlyand secrete mucus.
Functions:1.Absorption 2. Secretion
Ciliated columnarand cuboidalepithelium:
Theyareciliated. Border ofcellcontaining cilia containsbasalparticles ina
row. Theyare found in trachea, fallopiantubes, CNS etc.
Functions: 1. Ciliarymovement to maintainflow ofmucus inone direction
2. In CNS, its functionis suggested to be circulation ofCSF.
Glandular-epithelium:Theyline the alveoliandductsofglands ex-salivary,
sebaceous, mammaryand intestinalglands.
Functions : 1. Formation ofnew substances & 2. Secretion
Compound epithelium: Compound epitheliumisclassified into -
1.Transitionalepithelium-consistingoffourlayersofcellsandlyingbetween
simple epitheliumandmanylayered stratified epithelium.

2. Stratified squamouscornified epithelium- consistingofmanylayers and
hornydue to deposition ofkeratin.
3. Stratified squamous noncornified epithelium - consisting of stratified
squamous epithelium, not keratinised.
4. Stratified columnarepithelium- consistingofseverallayers ofcolumnar
cells.
5. Stratifiedcolumnarciliatedepithelium- consistingofstratifiedcolumnar
epitheliumcontainingcilia.
Transitionalepithelium: It isfoundinpelvisofkidney,ureter,urinarybladder
and urethra etc.
Fig 2.2 Simple and Compound Epithelial Tissue
Functions:1. Protection 2. Preventionofreabsorption
3. Preventionofdrawing water fromblood and tissues.
Stratified squamous cornified epithelium : It is found in skin.Hairs, nails,
horns, enamelofteeth are modified stratifiedsquamous cornified epithelium.

Functions: 1. Protectionfromatmosphere
2. Protectionfrommechanicalpressure
3. Protectionfrominjuryand friction
Stratifiedsquamous non-cornifiedepithelium:It is foundincornea, mouth,
pharynx, oesophagus, analcanal, urethra, vagina and cervixetc.
Functions:Mechanicalprotection
Stratified columnar epithelium: It is foundinconjunctiva, pharynx,
epiglottis, cavernous portionofurethra etc.
Stratified columnarciliated epithelium: It isfound inlarynx, soft palate etc.
2.2.2.2 Connective Tissue
Connective tissue is also called mesenchymaltissue. It is developed from
mesoderm. It serves the function of binding two tissues. Cells willbe less and
intercellular matrixwillbe abundant.
Severaltypes ofconnective tissue are -
(a)Areolar tissue (b)Adipose tissue
(c) Whitefibrous tissue (d)Yellowelastic tissue
(e) Reticular tissue (f)Blood
(g)Hemopoietic tissue (h) Cartilaginoustissue
(i) Osseous tissue (j) Jellylike tissue
(k)Reticuloendothelialtissue
Areolar tissue : It is supporting and packing tissue. It is distributed
betweenmuscular,vascularandnervoustissues. It isdistributedinsubcutaneous,
subserous and submucous tissues. It iscomposed offibres and cells. Spaces in
the networkoffibres is filledwithground substance. Fibrescontained are white
or collagenous fibres and yellow elastic fibres.
Types ofcells found in areolar tissue are -
(a) Fibroblasts (b) Histiocytes.
(c) Basophilic cells (d) Plasma cells
(e) Pigment cells (f) Mast cells
(g)Lymphocytes (h) Monocytes

Adipose tissue : It is also knownas loose connective tissue. It contains fat
inside fat cells. It is found below skin in mesentery, omentumetc. It prevents
injuryto organs. It gives shapeto limbs.
It storesenergyintheformoffat. It helps inregulationofbodytemperature.
Fig 2.3 Different Connective Tissues
White fibrous tissue : It is made of white firbres formed by fibroblasts.
Fibrocyte Polymorphonuclear
leukocytes
Fat cell
Eosinophil
Mast cell
Elastic fibres
monocyte
Macrophage
Plasma cell
Collagenous
fibres
Perichondrium
lacuna
Chondrocyte
Hyaline cartilage
Areolar connective
tissue
Fat globule
Fat cell
Capillary
connective
tissue cells
Adipose connective tissue Fibrouscartilage
Fat globule
Chondrocyte
Collagenous
fibers
Cell
Reticular
fibres
Perichondrion
Chondrocyte
Lacuna
Elastic fibres
Reticular connective tissue Elastic cartilage
Reticular connective tissue Bone
Collagenous
fibres
Fibroblast
Dense connective tissue

These fibres are non branching and present in bundles. They are present in
tendons and ligamentsoflimbs. It is made ofcollagen.
Yellow elastic tissue : It is another varietyoffibrous tissue. It is yellow in
colour. Fibresare thicker, bundles arewavy, but follow astraight course. Fibres
appearangular. Fibresaremadeofelastin.It is most resistantto manychemicals.
It is digested bypancreatin.
It is found in areolar tissue throughout body. It is inconcentrated formin
ligamentumnuchaeofquadrupeds and ligamentumflava ofvertebra. It is also
present inbronchi, larynx, arterialwallsetc. It isfunctionsasstrong elasticrope.
It is serves to maintain circulationand blood pressure byits elastic recoil.
Reticulartissue: Reticulartissueissimilartowhitefibroustissuewithcertain
differences. Reticular tissueis widelydistributed andformsbasement membrane
ofmanyepithelia. It is found inspleen, liver, lymphand bone marrow etc.
Blood : Bloodis fluidconnective tissue ofbody. It isdealt indetailinBlood
chapter.
Haemopoietic tissue : There are two types ofhaemopoietic tissues. They
are -
(a) Myeloid tissue (b) Lymphatic tissue
Myeloidtissue: Myeloidtissueisbloodformingtissueaswellasphagocytic.
Myeloidtissueissynonimouslyusedforbonemarrow. ‘Myelos’meansmarrow.
There are two types of bone marrow
(a) Red bone marrow ...Active form
(b)Yellow bonemarrow - Inactive form.
Red cells are produced in red bone marrow. In foetal life, most of the
bones containred bone marrow. Inpostnatallife and withadvancement ofage,
red bone marrowis located onlyinupper ends ofhumerus andfemur, bones of
skull, thorax, vertebrae and pelvic innominate bones. Yellow bone marrow
occupies the spacewhere redbone marrowwillnot be present.Althoughhalfof
the bone marrow(red bone marrow) isactive and halfis inactiveinadult, active
halfisenormouslyfunctional.
Lymphatic tissue:Lymphatic tissue is two types -
(a) Noncapsulated lymphnodules present inloose connective tissue.
(b) Capsulatedlymphtissue present inlymphorgans - lymphnode, spleen,
thymus, tonsils.

Cartilaginous tissue :It is connective tissue, whichisintermediate between
fibrous tissue and osseous tissue in firmness and elasticity. Components of
cartilaginous tissue are cartilage cells, chondroblasts, inter cellular ground
substance called matrix, fibres and two types ofproteins called chondromucoid
andchondroalbumoid.Chondromucoidonhydrolysisgiveschondroitinsulphate.
Cartilaginous tissue isdivided into three classes.
(a) Hyalinecartilage (b) Fibrocartilage (c)Elastic cartilage.
Hyaline cartilage : It ismade ofcartilaginous cells and clear homogenous
ground substance. Cartilagecells are also called chondrocytesandoccupysmall
emptyspacesinmatrix.Thesesmallemptyspacesinthematrixarecalledlacunae.
Matrixis solidintercellular substance ofcartilageor bone. It isdistributed inthe
articular end ofbones.
Fibrocartilage: Thistypeofcartilagehasgreat tensilestrengthwithflexibility
and rigidity. It can stand with shearingforces. It is foundinintervertebraldiscs,
menisci of knee joints, mandibular joints, pubis symphisis, linings of tendon,
grooves inbones etc.
Elastic cartilage : It is in between fibrous tissue and osseous tissue. It is
yellow in colour and contains elastic fibres. It differs fromhyalinecartilage as it
contains large number ofelastic fibres inthe matrix. It is distributed in external
ear, epiglottis, eustachiantube and somelaryngealcartilages.
Elastic cartilagestrengthens attached organs.
Jellylike connective tissue : It is an embryonic formofareolar tissue
Cells are large fibroblasts.Afew macro phages andlymphocytes are also
present. Ground substanceis mucinin nature. It is found inumbilicalcord. It is
called asWharton’s jellyhere. Vitreous humour ofeye ballis composed ofthis
tissue inadult life.
Reticuloendothelialtissue : It possesses various typesofconnective tissue
cells, widely distributed in body. Main functions are phagocytosis, antibody
formation, erythropoiesis, haemolysis etc.
Osseous tissue : Osseous tissue constitutes skeleton. It is the hardest
connective tissue of body. It is made of bone cells and intercellular ground
substance. There are three types of bone cells. They are - Osteoblasts,
osteocytes and osteoclasts. Organic part ofintercellular ground substance is
made ofosteocollagenousfibres, bound byossein.
There are two types ofbone tissues according to densityand hardness.

Theyare (1) Compact bone tissue.
(2) Spongy bone tissue
Outer layer ofallbones and shaft is compact bone tissue. Innerparts offlat
bones, rounded ends of long bones, body of vertebrae posses spongy bone
tissue.
Bone is covered with periosteum. Periosteumhas two layers- Outer layer
andinnerlayercalledcambium. Cambiumisosteogenicinitsfunctionsto produce
osteoblastsandosteoclasts.Endosteumistheliningmembraneofmarrow cavity.
It possesses osteogenic and haemopoietic functions. Bursae consist of small
sacs ofconnective tissuewithsynovialfluid. Bursae act likecushions and relieve
pressure in moving parts. Bone cavityis the hollow space in side the bone and
filled with bone marrow. Bone marrow is two types - Red bone marrow and
yellow bone marrow. Further reference ofbone marrow can be had at myeloid
tissue.
Fig 2.4 BoneTissue
Transversesectionofbone:T.S. ofboneundermicroscopeshowshaversian
systemconsistingof-
1. Centralhaversian canal
2. Lamellae
3. Lacunae
4. Canaliculi
Centralhaversiancanalcontainsbloodvessels, nervesandlymphaticvessels.
Lamellae are layers of bone deposited in concentric circles around haversian
Lacunae are interlamellarspaces. Canaliculiare minute canals joining lamellae
and communicating withcentralhaversiancanal
Compositionofbone
Lamellae
Canaliculi
Osteon
Periosteum
Volkmann’s Canal
Osteon of compact bone
Trabeculae of spongy bone
Haversian canal

Ossification Refer to Bones and Joints.
Types of bones
2.2.2.3 Muscular Tissue
It istypeoftissuehavingontractileabilityonexcitation. Ithasalso property
ofconductivity.Therearedifferent types ofmusculartissues.Theirclassifications
are based onphysiologicaland anatomicalaspects.
Types ofmuscular tissues based onstriation : Onthis basis, theyare two types
1. Striated muscles
2. Nonstriated muscles.
Fig 2.5 Types of Muscular Tissue
Fig 2.6 Types of Muscular Tissue
Striated muscles have cross striations. Non striated muscles do not have
Cardiac Muscle Cell
Skeletal muscle cells
Smooth muscle cell
Cardiac Skeletal
Smooth

cross striations and are plain.
Types ofmuscular tissues onthebasis ofcontrol:
On this basis, theyare two types
1. Voluntarymuscles
2. Involuntarymuscles
Voluntarymusclesareunder volitionalcontrol. Involuntarymuscles are not
undervolitionalcontrol.
Types ofmuscular tissues onthebasis ofdistribution:
On this basis, they are
1. Skeletalmuscles 2. Cardiac muscle 3. Visceral muscles.
Skeletalmuscles are attached to bones. Theyare under the controlofwill
power. Hence they are voluntary muscles. Fibres of skeletal muscles show
striations. Hence theyare also striated muscles.
Epimysiumistheoutercoveringofskeletalmuscle. Perimysiumis the outer
coveringforsmallerbundlesofskeletalmuscle.Smallerbundlesintowhichskeletal
muscle is divided are called fasciculi. Each fasciculus contains muscle fibres.
Each fibre is covered byendomysium.
Histologyofskeletalmuscle fibres: Skeletalmuscle fibres are cylindrical.
Theyare elongatedwithseveralnuclei.
Dimensions ofskeletalmuscle fibres are - 1-40 x 0.01 - 0.1 mm2
Sarcolemma is the transparent cell wall of muscle fibre. Myofibrils are
bundles of myofilaments embedded in sarcoplasm inside the plasmalemma.
Sarcoplasm contains sarcosomes (mitochondria), small Golgi apparatus,
myoglobin, lipidglycogen, sarcoplasmicreticulum.
From electron microscopic studies, it is relevant that myofilaments are
formed bythread like proteinfilamentsofwhich, thicker oneis myosinfilament
(100A0 diameter)andthinnerone isactinfilament (50A0). Theycontainmultiple
flat nucleiinperipheryunder sarcolemma.
Cardiac muscle: It is involuntary, striated muscle of heart. It contracts
rhythmicallyandautomatically.
Main differences between skeletaland cardiac muscle are
1. Spontaneous nature ofrhythmicityand contractilityofcardiac muscle.

2. 3-D network ofFibresofcardiac muscle appearinglikesyncytiumunder
light microscope.
3. Single ovalshaped nucleus at the centre ofeach cell.
Visceral muscles: They are smooth, involuntary and plain muscles of
viscera. Visceral muscle fibres are smooth and elongated. They are fusiform
with tapering towards periphery. Fine longitudinal striations maybe found in
specialpreparation. Theycontainone ovalor rod shaped nucleus at the centre
ofeach cell.
2.2.2.4 Nervous Tissue
Nervous tissue constitutes nervous system. Nervous tissue is excitable
type tissue receiving and transmitting messages. It is composed of neurons&
neuroglia. Nervous system is ectodermal in origin. There are three types of
maters in nervous tissue. Theyare -
1. Graymatter- forming nerve cells2. White matter -forming nerve fibres
3. Neuroglia- holding nervecellsand fibres together andsupporting them.
Histogenesis ofnervous tissue: Nervous systemdevelops fromectoderm
and neutral plate (also called medullary plate). Medulloblasts give rise to
neuroblasts andspongioblasts. Neuralcells (Neuroblasts)passthroughdifferent
stages to give neurone. Spongioblasts are also called glialcells. Spongioblasts
give raiseto neuroglia.
Neuron:Neuronisthebasicfunctionalandstructuralunitofnervoussystem.
Parts ofneurone are -
1. Nerve cellbody(also called perikaryon or neurocyton or soma)
2. Nerve fibres (also called processes of nerve cells)
Nerve cell body : It is the part of neurone containing cell membrane,
neuroplasm and nucleus. Neuroplasm contains neurofibrils, nissl bodies,
mitochondria, golgi apparatus. Superficial reticulum of golgi, ribosome,
endoplasmicreticulum,centrosomeandinclusions. Neurofibrilsarefinefilaments
passing through neuroplasmfromdendrites to axon. Nisslbodies are angular
granules stained withbasic dyes.
Nerve fibres : Two types of nerve fibres (also called processes of nerve
cell) arise fromnerve cell. Theyare -
(a) Receptive processes called dendrons (also called dendrites)

(b) Dischargingprocesses called axon.
Fig 2.7 Structure of Neuron
Dendritescarryimpulsesfromother neurons andcarrythemtowardsnerve
cellbody.Axon carries impulses awayfromnerve cell.Axonconsists ofthree
parts - axis cylinder, myelin sheath and neurolemma. Axis cylinder contains
axoplasm, neurofibrils and mitochondria. Myelin sheath is absent over nerve
fibres within grey matter. It is present over nerve fibres after entering white
matter. Myelinsheathis also calledmedullarysheath. Fibrescoveredwithmyelin
sheath are called myelinated fibres and fibres not covered bymyelin are called
non myelinated fibres. Function of myelin sheath is insulation ofnerve fibre.
Nodes of Ranvier are points of absence of myelin in the myelinated fibres
(medullated fibres). Neurolemma is the homogeneousnucleated covering over
somatic and autonomic nerve fibres outside C.N.S. Myelinated fibres in brain
andspinalcorddo not have neurolemma. Neuroglia is specialtype ofinterstitial
tissue giving support and insulation. They are divided into- astrocytes, -
oligodendrocytes(oroligodendroglia) and microglia.
Fibres ofperipheralnerve trunks are divided into bundles. Individualfibres
are heldtogether byloose connectivetissue called endoneurium. Eachbundle is
covered bya sheath called perineurium. Epineurium is the toughenclosure of
whole nerve trunk.
Conclusion
Cell is the basic structuraland functional unit of living matter.. Tissue is
group ofcellsofsimilarityinstructure, functionand genesis.
Dendrites
Myelin SheathAxon
Terminal button

Summary
Cell is the basic structural and functional unit of body. Types of cells of
body are somatic cells and gonadalcells. Structure ofcellcontains cell wall,
cytoplasm and nucleus. Cytoplasm contains cytoplasmic organelles and
cytoplasmicinclusions.Cytoplasmicorganellesare-Endoplasmicreticulum, Golgi
apparatus, Mitochondria, Lysosomes, Ribosomes, Centrosomes etc. Nucleus
is the key structure of living cell. Nucleus is covered by nuclear membrane.
Nucleus consists ofchromatinand nucleolus. Tissue is defined asgroup ofcells
ofsimilarityinstructure,functionand genesis. Humanbodycontains following
types oftissues.
1) Epithelialtissue2) Connective tissue3) Muscular tissue& 4) Nervous
tissue
Epithelial tissue gives covering to other tissues by forming epithelial
membrane.
Types ofEpithelialtissues are- 1)Simple epithelium- consisting ofsingle
layer ofcells 2) Compound epithelium- consisting ofmultiplelayers ofcells.
Severaltypes ofconnective tissue are-a)Areolar tissue b) Adipose tissue c)
White fibrous tissue d)Yellow elastic tissue e) Reticular tissue f) B lo o d g )
Hemopoietic tissue h)Cartilaginous tissue i) Osseous tissue j)Jellylike tissue
k)Reticuloendothelialtissue.Musculartissueismainly3types.a)Skeletalmuscles
b) Smooth muscles&c) Cardiac muscle. Nervous tissue consists of neurons
andneuroglia.
Model questions
1. What is cell?
2. Mention the properties ofcell.
3. Explaintrilaminar structureofcellwall.
4. List out cytoplasmic organelles.
5. Explainendoplasmic reticulum.
6. Write the functions of a) Smooth E.R. b) Rough E.R.
7. What are the functions ofGolgiapparatus?
8. Writeabout mitochondria.
9. What are a) Lysosomes and b) Ribosomes ?

10. Write about plasmosin.
11. Write about first evidence ofdifferentiationofcellular mass.
12. Mention majorclasses oftissues ofhumanbody.
13. Define a) Simple epithelium b) Compound epithelium
14. Describe pavement epithelium.
15. Givethe distributionofpavement epithelium.
16. Write thedescriptionand distributionofcuboidalepithelium.
17. Write about columnar epithelium.
18. Mention the classesofcompound epithelium
19. Writethedistributionof
(a)Transitionalepithelium
(b) Stratifiedsquamous cornified epithelium.
20. Writethefunctions of
(a) Stratified squamousnoncornified epithelium.
(b)Stratifiedcolumnar epithelium.
21. What are the types ofcells found in areolar tissue?
22. Write about white fibrous tissue.
23. ExplainMyeloid tissue.
24. What are different types ofcartilaginous tissue?
25. Write aboutReticuloendothelialtissue.
26. What are types of bone tissue?
27. Give the T.S. of bone.
28. Mentiondifferent typesofmuscular tissues.
29. Explain (a)Epimysium
(b)Perimysium.
(c)Endomysium
30. Define (a) Sarcolemma

(b) Sarcoplasm.
31. Differentiate between skeletaland cardiac muscular tissues.
32. Write about visceralmuscles.
33. What isnervous tissue?
34. Write different types ofmaters ofnervous tissue.
35. Explainhistogenesisofnervous tissue.
36. What are parts ofneurone?
37. Mention types ofnerve processes.
38. Define (a) Receptive processes ofnerve cell.
(b) Discharging processes ofnerve cell.
39. Write about Soma.
40. Define (a) Myelinated nerve fibres.
(b) Nonmyelinated nerve fibres.
41. Explain (a)Endoneurium.
(b) Perineurium.
1. Write thestructure ofcell.
2. Classifytissues.

UNIT
Respiratory System
3
Structure
3.1Definition
3.2 Parts ofRespiratorySystem
3.3 Summary
Learning Objectives
• Student should know the structureofrespiratorysystem.
• Student should understandabout respiratorymuscles.
3.1 Definition
It isthesystemconsistingofpartsconcenred withinhalationand exhalation.
3.2 Parts of the Respiratory System
1. Nose
2. Pharynx
3. Larynx
4. Trachea

Fig 3.1 Respiratory System
Theylead to the lungs.
5. Bronchi
6. Bronchioles
7.Alveolar ducts
8.Alveoli
Theyarewithinthelungs.
Upper respiratorytract extends fromuppernares to the vocalcord. Lower
respiratorytract extends fromvocalcordto the alveoli
1. Nose
It isthepart ofrespiratorysystemthroughwhichAirisinhaledinandexhaled
out.
External nose: It is the visible part of nose. It is formed bythe two nasal
bones and cartilage. It is covered byskin. There are hairs inside.
Nasal Cavity : It is a large cavity divided by a septum. It is lined with
ciliated mucous membrane. It is extremelyvascular.
Anterior nares: Theyare the openings whichlead in.
Poserior nares:Theyare similaropeningsat thebackandlead into pharynx.
Roof: Roofofthe noseis formed byethmoidbone at the baseofthe skull.
Floor: Floor ofthe nose is formed bythe hard and soft palates at the roof
ofthemouth.
Nasal Cavity
Pharynx
Larynx
Lung
Bronchus
Bronchiole
Nostril
Pleurn
Trachea

Paranasal sinuses: They are the hollows in the bones surrrounding the
nasalcavity, whichare lined withmucous membrane and openinto nasalcavity.
Maxillarysinus lies below the orbit and opens through the lateralwall of the
nose.
Frontalsinus lies above the orbit towards the midline ofthe frontalbone.
Ethmoidalsinusesare contained withinthe part oftheethmoid bone separating
the orbit fromthe nose. Theyare numerous .
Sphenoidalsinus lies in the bodyofthe sphenoid bone.
2. Pharynx
It lies betweenNasalcavityand larynx.
Pharynx isdivided into three parts. Theyare.
1. Naso pharynx 2. Oro pharynx & 3. Laryngo pharynx
Naso pharynxlies between nasal cavityand oro pharynx.It is lined with
ciliatedmucousmembranewhichiscontinuouswithliningofthenose.Oropharynx
lies in between Naso pharynx and laryngopharynx. Its lateral wall contains
collections oflymphoidtissue called tonsils. Laryngopharynxisthe lowest part
ofpharynx. It lies behind larynx.
3. Larynx
It lies below pharynx and abovetrachea. It is continuouswithoropharynx.
Musclesofthe neck lieinfront oflarynx. Laryngopharynxandcervicalvertebrae
lie behind larynx. Lobes ofthyroid glandlie on the eitherside oflarynx.
Larynx is composed of several cartilages. They are joined together by
ligaments and membranes.
Cartilages ofLarynx are-
1. Thyroid cartilage. 2. Cricoid cartilage.
3.Arytenoidcartilages. 4. Epiglottis
Thyroid cartilage : Thyroid cartilage is formed with two flat pieces of
cartilage. It is the largest upper part. Thyroid cartilage is lined with stratified
epithelium. Lowerpart is lined withciliated epithelium.
Cricoid cartilage: It lies belowthe thyroidcartilage. Itsshapeis like signet
ring. It is broad at theback. It is lined with ciliated epithelium.
Arytenoid cartilages : Theyarea pair ofsmnallpyramids. Theyare made
ofhyaline cartilage. Theyare located on the broad portionofcricoid cartilage.

Vocalligamentsare attached to them. Chink is thegapbetweenvocalligaments.
Epiglottis:Epiglottis isa leafshaped cartilage.It is attached to the inside of
the front wallofthyroid cartilage. During swallowing, larynx moves upwards
and forward and its opening is occluded byepiglottis.
4. Trachea
It is also called as wind pipe. It is a cylindricaltube. It is about 11 cm. in
length. It begins at the lower end ofpharynx. It divides into two bronchiat the
leveloffifththoracicvertebra.ItismadeofsixteentotwentyC-shapedincomplete
cartilages. Theyareconnected byfibroustissueat the back. It islined byciliated
epithelium. Ciliatedepitheliumcontains goblet cellswhichsecrete mucus.
5. Bronchi
Tracheadivide into right and left bronchi.Tracheaand bronchi, combinedly
are invertedYshaped. Right bronchus leads into right lung and left bronchus
leads into left lung. Right bronchus isshorter thanleft bronchus. It is also wider.
Bronchiaremade up ofcomplete rings ofcartilage.
6. Bronchioles
Bronchioles arethe finest branches ofbronchi. Theydo not have cartilage.
Theyare lined bycuboidalepithelium. Bronchioles become further smaller to
formterminalbronchioles.Terminalbronchioles are a single layer offlattened
epithelialcells.
7.Alveolarducts
Terminal bronchioles divide repeatedly to formminute passages. These
minute passages are called alveolar ducts.Alveolar sacs and alveoliopen from
alveolar ducts.
8. Alveoli
Alveoliare thefinalterminations ofeachbonchi. Theycotainathinlayer of
epithelialcells. Theyare surrounded bynumerouscapillaries. Capillarynetwork
is the site ofexchange ofgases between blood and air in the alveoli.
Lungs
Lungs are the principalorgans concerned with repiratory process. They
are two innumber. Theyare spongyorgans. Theylie in the thoracic cavityon
either side ofheart and great vessels. Theyextend formroofofthe neck to the
diaphragm. Ribs, costalcartilages and intercostalmuscles lie in front oflungs.
Behind them-ribs, intercostal muscles and transverse processes of thoracic

vertebrae lie. Mediastinumis a block oftissue inbetweenthe two lungs. Within
mediastinum lie-Heart, great vessels, trachea, oesophagus, thoracic duct and
thymusgland.
Lungs are conicalinshape with apexabove and base below.Apex slightly
rises over the clavicle. Base is near the diaphragm. Each lung is divided into
lobesbymeansoffissures. Rightlungisbiggerthanleft lung. Right lungisdivided
into three lobes. Left lung is divided into two lobes. Each lobe is divided into
number oflobules. Eachlobe contains a smallbronchialtube. This tube divides
and sub divides to end inair sacs.
Pleura is a serous membrane covering the lungs. It contains two layers.
Inner layer close to the lungs is called as viscerallayer. Outer layer is called as
parietallayer. Pleuralfluid lies inthe space betweenvisceraland parietallayers.
Hilumis a triangular shaped depressionon the concave medialsurface of
the lung. It is a vertical slit on each lung through which structures like blood
vessels, nerves and lymphatics pass. Root of the lungs (Hilum) is formed by
pulmonaryarteries,pulmonaryveins, bronchialarteries,bronchialveins, bronchi,
lymphatic vessels. Pulmonaryarteries carrydeoxygenated blood to lungs from
heart. Pulmonaryveinscarryoxygenatedbloodfromlungsto theheart. Bronchial
arteries are the branches of thoracic aorta carrying arterial blood to lungs.
Bronchial veins are the vessels carrying venous blood of lungs to superior
venacava.
Respiratory muscles
Intercostalmusclesand diaphramarerespiratorymuscles. However, during
forced respiration sternocleidomastoid, scalenie, mylohyoid, platysma and
abdominalmusclesalso participa
Intercostalmuscles:Theyare two seriesofmuscles. Thustheyare 11 pairs.
Theyare externalintercostalmuscles and internalintercostalmuscles. Theyare
innervated byintercostalnerves.
Diapharagm : It is a large dome shaped sheath of muscle. It separates
thoracic cavityfromabdominalcavity. It is innervated byphrenicnerve oneach
side.
Summary
Respiratorysystemissystemconsistingofpartsrelatedwithrespiration.
Parts of respiratory system are -Nose, pharynx, larynx, trachea, bronchi,
bronchioles, alveolarducts and alveoli.Alveoliare the ultimate sitesofgaseous
exchange. Lungs aretwo innumber. Right lung is divided into three lobes. Left

lung is dividedinto two lobes. Eachlobeis divided into lobules. Pleura is serous
membrane covering lungs. Hilumon eachlung is a depression through which
blood vessels, nerves, lymphatics etc. passinto the lung.
Respiratorymuscles are intercostalmuscles and diaphragm.
Conclusion
Respiratorysystemisthe systemconsisting ofpartsrelated to respiration.
Respirarorymuscleshelp inrespiration.
Model questions
1. What are the parts ofrespiratorysystem, whichlead into lungs?
2. Name theparts ofrespiratorysystemwhichlie within lungs.
3. Mention the parts ofnose.
4. What are the parts ofpharynx?
5. Name thecartilages oflarynx.
6. Explain trachea.
7. What are a) Bronchi b) Bronchioles?
8. Write about alveoli.
9. What are respiratorymuscles?
10. Name the series ofintercostalmuscles.
11. Howmanypairs ofintercostalmuscles are there?
12. What are the nerves innervating intercostalmuscles?
13. Describe diaphragm?
1. Write the anatomyofrespiratorysystem.

UNIT
Digestive System and Hepato
Billary System
4
Structure
4.1Introduction
4.2. PartsofDigestive Tract
4.3 Peritoneum
4.4AccessoryOrganofDigestive System
Learning Objectives
• Student shouldknowtheanatomyofDigestiveandhepatobiliarysystem.
• Studentshouldalsoknowthestructuresofabdomensupportingdigestive
organs.
4.1 Introduction
Digestivesystemconsistsofgastrointestinaltractandvariousglandsattached.
Length ofthe tract is about 8-10 metres. It starts with mouth and ends with
anus.
4.2 Various parts of the Digestive Tract
1. Mouth 2. Pharynx
3. Oesophagus 4. Stomach

5) Smallintestine6) Large intestine
7) Rectum 8) Anus
Fig 4.1 Digestive SystemandHepatoBiliary System
Accessory organs of the digestive tract -
1. Teeth 2. Three pairs ofsalivaryglands
3. Hepato biliarysystem 4. Pancreas
Mouth
It is the first part ofthe digestive tract. It opens throughupper and lower
lips. Roofofthe mouth is called as palate. It is dome shaped. Front part ofthe
roofishard palate and back part ofthe roofis soft palate. Walls of the mouth
are formed bymuscles of cheeks. Mouth is lined bymucous membrane.It is
continuous withskinoflips andmucous lining ofpharynx. Lips enclose orbicu-
laris orismuscle. This muscle keeps themouthclosed. Pharyngealtonsils are on
either side at the back oforalcavity. Uvula hangs down fromlower border of
soft palate.

Fig 4.2 Mouth
Tongue
Tongue isat thebaseofthemouth. It is a musculo-membranousstructure.
It consists of1. Stratified and cornified epithelium2.Voluntary, cross striated
muscle fibres and 3. Glands.Epitheliumoftongue is modified into papillae and
taste buds. Under surface of the anterior part of tongue is connected to the
floor ofthe mouthbyfrenulum. Frenulumis a foldofmucous membrance.
Teeth
Man is provided with two sets of teeth in his life. First set is called as
Deciduous teeth or primary teeth. They are 10+10 in number. They erupt
through the gums during first and second years of life. Second set strarts re-
placing the first set at about sixthyear and process is complete bytwentyfifth
year. Second set remains upto old age and is called as permanant teeth.
Permanant teethare 16+16 innumber.Four types ofteeth are there. They
are -
1. Incisor teeth (I)
2. Canine teeth (C)
3. Premolar teeth(P)
4. Molar teeth (M)
Upper teeth are attached to upper Jaw and Lower teeth are attached to
lower Jaw.
Gingiva
Hard Palate
Uvulla
Papillae of tongue
Premolar
Canine
Lips
Soft palate
Palatine to nasal
Molars
Tongue

Arrangement ofpermanat teeth
M P C I I C P M
Right upper jaw 3 2 1 2 Left upper jaw 2 1 2 3
Right lower jaw 3 2 1 2 Left lower jaw 2 1 2 3
Structure of tooth:
Each tooth consists of three parts.Theyare - 1) Root 2) Neck 3 )
Crown
Root is embedded in the alveolus of maxilla or mandible. Neck is the
constricted part betweenroot and crown. Crown is the part projecting beyond
thegum.
Fig 4.3 Structure ofTooth
Tooth is composed ofthree substances. Theyare -
1. Dentine 2. Enamel 3. Cementum
Dentine formsmajor part oftooth. Enamelis the outercovering ofcrown.
It isthe hardest substance. Cementumis inthe neck. It is ashard as bone.
Crowns of Incisor teeth are chisel shaped. Crowns of canine teeth are
large and conical. Crowns ofpremolar teeth are bicuspid and almost circular.
Crowns ofMolar teeth are broad and tetra or penta cuspid.

Salivary glands
There are three pairs ofsalivaryglands in the mouth. Theyare-
1. Parotid
2. Submandibular and
3. Sublingualglands.
Fig4.4 Salivary Glands
1. Parotid glands : They are the biggest salivary glands .One gland is
present below each ear. Eachgland opens on inner side ofcheek opp osite to
the second uppermolar teeththrough its duct. Ducts ofthe parotid glands are
called as Stenson’s ducts.
2. Submandibular glands : Theyare also called asSubmaxillaryglands.
Theyaresmaller than parotidglands. One oneach side lies under the angle of
Jaw. Eachsubmandibular gland has a duct called wharton’s gland. Theyopen
near the midline under the tongue.
3. Sublingual glands: They are the smallest salivary glands. They lie
under the tongue. Theypour their secretions in to the mouth through several
openings.
Pharynx
Pharynx lies between mouth and Oesophagus.It is divided into 1.Naso
pharynx 2. Oropharynx and 3. Laryngopharynx.It serves commonlyfor both
digestive and respiratorysystems.Base ofthe skullforms its roof. There lies a
Parotid Gland
Sublingual gland
Submandibular gland

lymph node called adenoid at the back of nasopharynx.
Fig 4.5 Pharynx
Oesophagus
It ismuscular tube extending betweenpharynxand stomach.
Trachea and vertebralcolumn lie inthe front and back of oesophasus re-
spectively. It lies in both thoracic and abdominalcavities. It passes fromtho-
raciccavityintoabdominalcavitythroughoesophagalopeningofthediaphragm.
Ontheeach side ofupperpart ofoesophagus, are present-corresponding com-
moncarotid arteryand part ofthyroid gland. Oesophagus beginsat thelevel
of6th vertebra, enters the abdomen at the leveloftenththoracic vertebra and
ends at the levelof11ththoracic vertebra.
Cross section ofoesophagus shows similar structure as remainder ofali-
mentarycanal. It shows thefollowing layers.
(1) Muscular coat (2) Submucous coat (3) Mucous coat
It isdevoid ofSerosa. Upper one third ofoesophagus consists ofstriated
muscles. Lower one third contains smoothmuscles and middleone third con-
tains bothtypes ofmuscles.
Stomach
Stomach is the most dilated part of digestive tract. It is J shaped. It is
situated betweenthe end oftheoesophagus and begining ofthe smallintestine.
It liesbelowthe diaphragminthe abdominalcavity.Itsmajorpart is to theleft of
the mid line.It distends when it isfilled withfood. Averagecapacityofstomach
Tongue
Epigolotis
Nasopharynx
Oropharynx
Laryngopharynx
Esophagus
Larynx
Cartilage

is 1.5 L in an adult.Stomachhas two surfaces,two curvatures two ends,three
parts and two sphincters.Theyare as follows.
The two surfaces ofstomach are- 1.Anterior surface 2. Posterior surface.
Two curvaturesare- 1. Lesser curvature 2. Greater curvature.
Fig 4.6 Parts of Stomach
Three partsofstomachare -1. Fundus (upper portion) -above the cardiac
sphincter 2. Body (middle portion) - between fundus and pylorus. 3. Pylorus
(lower portion) - below incisura angularis. Pylorus is subdivided into pyloric
antrtumandpyloric canal.Two ends ofstomachare
1. Cardiac end guarded bycardiac sphincter.
2. Pyloric end guarded by pyloric sphincter.
Two sphincters of stomach are-
1. Cardiac sphincter (at the begining).
2. Pyloric sphincter (at the ending)
Fig 4.7 Internatl Structure of Stomach
Fundus
Cardia
Lesser Curvature
Greater Curvature
Pylorus

Histologically, it shows
1. Outer serous coat, which is the viscerallayer ofperitoneum.
2. Muscular coat made ofthree layers consisting oflongitudinal, circular
and oblique unstripped musclefibres.
3. Submucous layer made ofloose areolar tissue
4. Mucousmembrane containing numerous folds called as rugae.
Small intestine
It is a coiled tubular structure about 6 metres long. It extends from
pyloricsphincter to itsjunctionwithlargeintestineat the ileo-caecalvalve. It lies
within the curves oflarge intastine inthe centraland lower parts ofabdominal
cavity.
It is divided into three parts. Theyare
1. Duodenum 2. Jejunum 3. Ileum
Duodenum:It isthe first part ofsmallintestine. It is C shaped. Duct from
gallbladder, bile duct and pranereatic duct open into duodenumthrough the
hepatopanereaticampulla.Hepatopancreatic ampulla is guarded bya sphincter
like muscle. Head ofthe panereas lies in the curve ofduodenum.
Jejunum: Jejunumis the upper two fifth part of remainder of the small
intestine. It lies inbetweenduodenumand ileum. It is bound behind bya fold of
peritoneum called mesentery which carries blood vessels, autonomic nerves
and lymphatics to jujunum. It has severalglands.
Ileum : It is the distal three fifth of long and coiled up smallintestine. it
extends betweenJejunumand caecum(begining oflarge intestine). There are
numberofpeyer’s patches inileum. Theyare minutelymphoid structures. Ileum
has similar structure as Jejunumbut more villi. Illeumalso contains digestive
glands. But theyare less thanin the jejunum.
Structure ofsmallintestine : It contains four layers similarlyas the remain-
der ofalimentarytract. Theyare -
1. Serous coat, formed ofperitoneum(Serosa)
2. Muscular coat witha thinexternallayer oflongitudinalfibresand a thick
internallayer ofcircular fibres.(Museularis externa).
3) Submucouscoat containing blood vessels, lymph vessels and
nerves (submucosa). It contains Brunner glands.

4. Mucousmembrance(Muscularisinterna/Muscularis mucosa)
Structure ofsmallintestine contains goblet cells in addition to villi. They
produce mucus.
Fig 4.8 Parts of Small Intestine
Lining ofthe mucous membrance has the following three features. They
are
1. Mucous membrane contains circular folds. Unlike the rugae of
the stomach, theyare permenant. They enhance the surface area avail
able for absorption.
2. It contains fine hair likeprojections called villi, eachcontins a lymph
vessel called lacteal and blood vessels.
3. It issupplied withglands ofsimple, tubular type. Theysecrete intestinal
juice.
Smallintensinecontains lymphoid tissue consideribly. Mucous membrane
contains solitarylymphatic follicles. Theyare most numerous inthe lower part
ofileum.
Large intestine
Ileum of the small intestine merges into large intestine. There is
ileocaecalvalveat thejunctionofileumand large intestine. Colonmeasurs about
1.5 metres inlength.
Large intestine consistsoffollowing parts.
Theyare- 1. Caecum.
2. Vermiformappendix.
Small Intestine
Duodendum
Jejunum
Ileum

3.Ascending colon.
4. Transverse colon.
5. Descending colon.
6. Sigmoid colon.
.
Fig 4.9 Parts of Large Intestine
1. Caecum: It is a short rounded sac. It lies in the right iliac fossa. It
begins at theileoeacealvalve where ileumandcaecumjoin. It iscontinuous with
ascending colon.
2. Vermiformappendix: It springsout fromcaecumat aboutaninchfrom
ileocaealvalue. Lumen ofthe appendixcommunicates with that ofcaecum. It
contains same four layers as intestine but the submucous layer contains lym-
phoid tissue. It is a vestegealorganin human body.
3. Ascending colon: It ascendsupwards fromcrecumandinfront ofright
kidney. It turns to left below the liver. It forms into transverse colon.
4. Transverse colon:It lies transversely below the stomach. It is sus-
pended fromitsownmeserteryfromtheposterior abdominalwall. It extends to
the left and merges with descending colon at the lower surface of spleen. It
extends betweenthe lower surfaces ofliver and spleen.
5. Descending colon: It is situated vertically on the left side ofabdomen.
It extendsfrom transverse colonand merges with sigmoid colon.
6. Sigmoid colon: It lies in the pelvis. Hence it is also called as pelvic
colon. It is situated at the left. It forms loops. It has amesentery ofits own. It
continues belowwithrectum.
Stomach
Large Intestine
Small Intestine
Sigmoid colon
Anus
Rectum

Structure of large intestine: Large intestine has the same structure as
smalll intestine. Differenceis -longitudinalmuscles are arrangedinthree bands.
Mucous membrane does not containvilli.
Rectum: It isa straight tube lying inlower posterior part ofpelvic region.
It is 12 cmlong extends fromsigmoid colon to analcanal. It issituated behind
urinary bladder, prostate and seminal vesicles in male and behind uterus and
vagina infemales. It lies as a straight tube on the inside ofsacrumand coccyx.
Mucous coat ofrectumhas longitudinaland transverse folds. Lower portionof
rectumiscalled as rectalampulla. Rectalampulla is a dilated part.
Anus:Rectum ends in anus. It is about 1 inch long. It is a small canal
guardedbytwo sphincters. Internalsphincterisinvoluntaryandexternalsphincter
isvoluntary.
4.3 Pritoneum
Peritoneum is a serous membrane. In males it is a closed sac lining the
abdomen. In females, free ends ofuterine tubes openinto peritonealcavity.
Peritoneumconsists oftwo layers. Theyare
1. Parietallayer lining the wallsofabdominalcavity.
2. Viscerallayercovering the abdominalorgans.
Peritonial cavity: It is the space between parietal and visceral layers of
peritoneum.
Omenta: Folds of the pritoneum connected to stomach are called as
omenta
Omenta are divided into -
1. Greateromentum
2. Lesseromentum
Greater omentumhangs fromlower borderofstomachto thefront surface
ofsmallintestine. Lesser omentumextends fromlower border ofliver to the
lesser curvature ofstomach.
Mesentery: Mesenteryis the fold ofperitoneumwhichattaches different
parts ofsmallintestine to the posterior abdominalwill. Blood vessels, nerves
and lymphatics enterthe intestines throughmesentery.
Pelvicperitoneum:Part oftheperitoneumlyinginthepelvicregioniscalled
as pelvic peritoneum.

Peritonealligmemts: Foldsoftheperitoneumconnectingorganslike liver,
uterus etc to the posterior part ofabdominalwallare called as peritonealliga-
ments.
Pouch ofDouglas:Sac ofperitoneumbetweenrectumanduterus is called
as pouchofDouglas.
Regions of abdomen: Abdomen is divided into nine regions.
1. Right hypchondrium 2. Epigastrium
3. Left hypochondrium 4. Right lumbarregion
5. Umbilicalregion 6. Left lumbar region
7. Right iliac fossa. 8. Hypo gastrium
9. Left iliac fossa.
4.4 Accessary organs of Digestive System
Teeth and salivaryglands are covered under mouth.
4.4.1 Hepatobiliary System
4.4.1.1 Liver
Liver is thelargest organinabdomen. It is thelargest gland inthe body. It
is situated inthe upper right part ofabdominalequity. It occupies almost entire
hypochondrium. It lies below the diaphragmunder the cover oflower ribs.
Lobes ofliver: Falciformligament dividesit into two lobes. Theyare-
1. Right lobe
2. Left lobe
Right lobeofthe lies overthe right colic flexureand right kidney. Left lobe
lies over stomach. Right lobe is bigger than left lobe. On the inferior surface
two bandsare present.Theysubdivide liver into four compartments.
1. Right lobe 2. Left lobe
3. Quadrate lobe 4. Caudate lobe.
Lobules ofliver : Liver consists oflarge number ofhepatic lobules. They
are hexagonalin shape. Diameter of each lobule is about 1 mm. Each lobule
has a smallcentralintra lobular vein, whichis a tributaryofa hepaticvein.
Portalcanals are present around the edges oflobules. Each portal canal
contains 1. Interlobularvein. 2. a branch of hepatic artery and

3. a small bile duct.
These three structurestogetherare called asportaltriad.Lobules consist of
liver cells. These cells are large cells. Liver cells are arranged in sheets ofone
cell thickness.They are called as hepatic laminae. Spaces between laminae
contain smallveins with many anastomoses and smallbile ducts called canali-
culi.
Surfaces ofLiver:
1. Superior surface. 2. Inferior surface.
3.Anterior surface. 4. Posterior surface.
- Superiorsurfaceofliverisincontact withinferiorsurfaceofdiaphragram.
- Inferior surface faces abdominalviscera.
-Anterior surface is separatedfromribs and costalcartilages bydiaphragm
-Posteriorsurfaceliesinfront ofvertebralcolumn,aorta, inferiorvenacavae
and lowerend ofoesophagus.
Fig 4.10 Liver Fig 4.11 Lobes of Liver
Blood supply
Hepatic arteryand portalveincarryblood to liver. Hepatic arterysupplies
oxygenated bloodto liver. It is a branchofcoeliac plexus. It inturnaraises from
abdominal aorta. Portalvein brings blood to liver fromstomach, spleen and
intestines. It divides into inter lobular veins. They subdivide and finallyform
centralveins. Onecentralveinlies incentre ofeachlobule. These centralveins
unite to form sublobular veins. Sublobular veins unite to form hepatic veins.

These hepatic veins join withinferior venacava and drainimpureblood ofliver
into inferior venacava.
4.4.1.2 Biliary system
Biliarysystemconsists of
1. Commonhepaticduct formed bytheunionofright andleft hepatic ducts
fromliver.
2. Gall bladder
3. Cystic duct fromgallbladder
4. Common bile duct formed byunionofcommonhepeticduct and cystic
duct.
Gallbladder
Gall bladder is a pear shaped organsituated at the under surface of right
lobe ofliver.
It consists ofthree parts.
1. Fundus. 2. Body 3. Neck
Layers ofgallbladder: It consists ofthree layers. Theyare-
1. Outer serous coat.
2. Middlemuscular coat
3. Inner mucous coat.
4.4.1.3 Pancreas
Pancreas is a soft grey ish pink coloured gland. It is about 12 to 15 cm
long. It lies transverselyacross the posterior abdominalwallbehind the stom-
ach. Pancreas has three parts.
1. Head 2. Bodyand 3. Tail.
Head ofthe pancreas lies within the curve ofduodenum. Tailextends as
for as the spleen. Bodylies between Head and tail. Pancreatic duct lies within
the organ. Pancreatic duct joins bile duct at the head ofthe pancreas and open
together into duodenumat heptopancreatic ampulla.
Pancreas is composed of lobules. Each consists of tiny vessel. All these
tinyvesselsleadto themainduct and end innumber ofalveoli. Alveolilined with
cells secrete the enzymes trypsinogen, amylase and lipase. Collections ofcells

called as Islets of langerhans are present in between the alveoli. Alpha cells
constitute 25 percent oftotalnumber ofIslets and beta cells constitute 75 per-
cent ofthetotalnumber ofIslets.
Conclusion
Digestive systemcontains the parts related to the functions ofingestion,
secretion, digestion, absorptionand excretion.
Summary
Digestive systemconsists ofGastrointestinaltract and various glands at-
tached. Major organs aremouth, pharynx, oesophagus, stomach, smallintes-
tine, large intestine, rectumand anus. These are concernedwith functions like
Ingestion, deglutition, absorptionand excretion. Accessoryorgans are teeth,
salivaryglands, liver and biliarysystem, pancreas etc.
Model Questions
Short Answer Type questions
1 List the mainparts ofDiagestive system.
2. Mentiondifferent accessoryorgans ofdiagestive system.
3. What are the two sets ofteeth?
4. Mention the typesofpermanant teeth.
5. Write the arrangement ofpermanant teeth.
6. What are the parts ofa tooth?
7. Mention thecomponents oftooth.
8. Howmanypairs ofsalivaryglands are there?What are they?
9. Write the locations ofsalivaryglands.
10. Name the ducts of
(a) Parotid glands
(b) Submandibular glands.
11. Mention different parts ofpharynx.
12. What are the layers in the cross section ofoesophagus?
13. Mention various parts ofstomach.

14. What are the surfaces of stomach?
15. Name the cuvatures ofstomach.
16. Write the names ofsphincters ofstomach.
17. List the layers ofstomach.
18. Mention the parts ofsmallintestine.
19. What arethe layers in the structure ofsmallintestine?
20. Define (a)Rugae (b)Villi
21. Write about vermiformappendix.
22. What are the lobes ofliver when viewed fromthe inferior surface of
liver?
23. What is a portaltriad?
24. Define (a) Laminae (b) Canaliculi
25. Name the surfaces ofliver.
26. Write the parts ofBiliarysystem?
27. Where is Gallbladder situated? What are its parts?
28. Name the layers ofgallbladder.
29. Mentionthe locations ofparts ofpancreas.
30. What are islets oflangerhans?
1. Define Digestive system. What arethevariousparts?Describe anatomy
of mouth.
2. Describe the anatomyofpharynxand oesophagus. Draw the diagrams.
3. Write the anatomyofstomach. Draw the diagramand label.
4. What are different parts ofsmallintestine?Explaintheir anatomywith
figures wherever required.
5. Write the anatomyoflarge intestine. Draw thefigure and label.
6. Explaintheanatomyofliver. Draw figure.
7. Explain gallbladder and pancreas.

UNIT
Cardio Vascular System
5
Structure
5.1Introduction
5.2AnatomyofHeart
5.3 ConductingsystemofHeart
5.4AnatomyofVascular System
5.5Types ofCirculation
Learning Activities
• Student willknow the anatomyofheart
• Student willknow the anatomyofvascular system.
• Student willknow the types ofcirculation.
5.1 Introduction
Cardiovascular system consists of Heart and Vascular system. It is well
organised blood transport systemofbody. Heart is the centralpumping organ.
Blood vessels constituting vascular systemare arteries, arterioles, capillaries,
venules and veins.

5.2 Anatomy of Heart
Heart lies onthe left upper part ofthoracic cavity. It lies between the two
lungs under sternum. It is broad above and conicalbelow.
5.2.1 Histology of Heart : Heart consists ofthree layers.They are-
1. Pericardium-outermost layer consisting of
(a) Visceralpericardium
(b) Parietalpericardium
(2)Myocardium-Middlelayermadeofcardiacmusclecellsandinterstitialcells.
(3) Endocardium- Innermost layer.
Fig 5.1 Structure of Heart
Pericardiumforms bag like structure between visceraland parietallayers
containing pericardialfluid.
5.2.2 Chambers of Heart
Heart has four chambers. Two ofthemare upper chambers called atria or
auricles. Lowertwo chambers are calledventricles. The two atriaare separated
byinteratrialseptum.Thetwo ventricles areseparaedbyinterventricular septum.
Atria are fillingchambers and ventricles arepumping chambers. Compared
to artia, ventricles are thicker since they are pumping chambers. Of the two
ventricles, wallofleft ventricle is three times thicker than that ofright ventricle
sinceleft ventriclepumpsoxygenatedbloodtoallpartsofbodyandright ventricle
pumps deoxygenated blood to lungs only.
Right atrium
Tricuspid valve
Right ventricle
Linoxygen blood
Inferior vena cavae Descending aorta
Oxygenated blood
Left ventricle
To the lungs
Pulmonary veins
Aortic valve
Mitrai valve
Left Atrium
Pulmonary veins
Pulmonary arteries
To the lungs
AortaSuperior vena cavae
Pulmonary valve

5.2.3 Valves of Heart
Opening between right artiumand right ventricle is guarded bytricuspid
valve. It prevents back entryofblood into rightatriumfromright ventricleat the
beginning ofventricular systole. Opening betweenleft atriumand left ventricleis
guarded by bicuspid or mitral valve. It prevents back entry ofblood into left
atriumat the beginning ofventricular systole - Pulmonarytrunk is guarded by
tricuspid semilunar valve which prevents back flow into right ventricle at the
beginingofventriculardiastole.Aortahastricuspidsemilunarvalvewhichprevents
back flow ofblood into left ventricle at the beginingofventricular diastole.
Chordae tendinae and papillary muscles:Papillary muscles arise from
ventricular walls. Chordae tendinae attach apicalend ofvalves and papillary
muscles. Theyprevent over distensionofvalves during diastole.
5.2.4 Blood Vessels attached to Heart
Blood vessels attached to heart are -
1. Superior and inferior venacavae - carrying deoxygenated blood from
parts ofbodyto right atrium.
2. Pulmonaryarterycarrying venous blood to lungsfromright ventricle.
3. Pulmonaryveins carryingoxygenatedblood fromlungstotheleft atrium
of heart.
4.Aorta carrying oxygenated blood to allparts ofbodyfromleft ventricle
of heart.
Bloodvesselssupplyingoxygenatedbloodto heart :Right andleft coronary
arteries arisingfromAorta supplyoxygenatedblood to heart.
Blood vessels drainingheart : Coronaryveins bringdeoxygenated blood of
heart into coronarysinus, whichopens directlyinto right atrium.
Ductus arteriosus: Ductus arteriosusis the vestigealremnant ofcord like
structurewhichexisted infoetallifebetweenarchofaortaand pulmonarytrunk.
In foetallife, it bypasses pulmonarycirculation. After birth, it closes, becomes
obsolete and atrophies.
Septum ovale : It is crescenteric mark on interatrialsetpum. It is closed
foramenovale that existed infoetus.
Foramen ovale : It is the opening in interatrial septum in foetal life. It
avoidsblood entryinto lungs infoetallife.After birth, it closesand formsseptum
ovale.

5.2.5 Cardiac centres
1. Cardio inhibitorycentre is dorsalmotor nucleus ofvagus inmedulla.
2. Cardio accelerator centreissituatedinlateralhorncellsofupper thoracic
segments of spinalcord.
5.2.6 Nerve supply to Heart
Sympathetic and vagusnerves supplyheart.
5.3 Conducting System of Heart
Systemofconducting impulses ofcardiac contractionconsist of-
(1) Sinoatrial node (SA node) (2) Atrioventricular node (AV node)
(3) Bundle of His. (4) Right and left branches of bundle of His. (5) Purkinje
fibres.
SAnode :It ispresent at theopeningofsuperiorvenacavainto right atrium.
It is called pacemaker ofheart. It is made ofmodified cardiac muscle fibres. It
measures about 5x20 mm.
AVnode: It ispresent inthe right atriumat the posterior part ofinter atrial
septum. It iscloseto theopening ofcoronarysinus. Cells ofAVnodeare cardiac
muscle fibres havinga few myofibrils.It measuresabout 2x5 mm.
Bundle of His : Maintrunk ofbundle ofHisis continuous withAV node.
It passes throughinterventricular septum. It is about 20 mmlong.
Right and left branches of bundle of His : Bundle of His divides into
right and left branches. Right branch is longer than left branch. Left branch
bifurcates into superior and inferior divisions.
Purkinjefibres: Theyarise frombrnachesofbundles ofHis.Theyspread
frominterventricular septumdirectlyto papillarymuscle and ultimatelyend in
sub endocardial network.Purkinje fibres have larger diameter than ordinary
cardiac muscle fibres. Purkinje fibres have diameterof50-70 whereas cardiac
muscle fibres have diameter of about 15 .
5.4 Anatomy of Vascular System
Blood vessels constitute vascular system. There are two types of blood
vessels mainly. Theyare arteries and veins.Arteries subdivide into arterioles.
Arteriolesendincapillaries. Capillariesaresinglelayeredthinvessels. Capillaries
uniteto formvenules.Venulesunitetoformveins.Arteriesarethevesselscarrying
oxygenated blood to tissues (except pulmonaryarteries). Veins are the vessels
carrying dexoygenated blood(except pulmonaryveins).

HistologyofArteries and Veins :Arteriesand veins consist ofthree layers
1. Tunica externa- outer layer madeoffibrous tissue andelastic tissue and
also called tunica adventitia.
2. Tunica media - middle layerofplainmuscles and network ofelastic
fibres.
3. Tunicainterna -innermost layermade ofendothelialcellsand also called
tunica intima.
Fig 5.2 T.S. of Artery andVein
Tunica media inarteries is thickeerthaninveins.
Valves ofVeins : Valves are present inveins (oflower limbs particularly).
Theyprevent back flow ofbloodfromheart. These valvesare semilunar pocket
like flaps. Theyare formed bylocalfolding ofintima.
Vasavasorum : Theyare blood vessels supplying blood to large arteries
and veins ofabove 0.1mmdiameter.
Sinusoids : Sinusoids and sinusoidalcappilaries are not true cappilaries.
Theyhave largersize thancapillaries. Continuous endotheliallining is absent.
5.4.1 Arteries of the Body
Aorta, arisingfromleft ventricleofheartisthemainarteryofbody.It consists
ofthree parts.Theyare-
1.Ascending aorta, giving offtwo branches
i. Right coronaryartery
Tunica Externa
Tunica Media
Tunica Interna
Lumen
Ealstic
Membrane
Arteries Veins

ii) Left coronaryartery. Coronaryarteries supplyblood to heart.
2.Arch ofaorta : Giving offthree branches and supplying blood to head,
neck and upper limb-
branches of arch of aorta are -
i) Innominate artery- dividing into
a) Commoncarotid artery
b) Right subclavian artery
ii) left commoncarotid artery
iii) left subclavianartery.
3. Descending aorta - divided into
i) Thoracicaorta - supplying bloodto wallofchest cavityand viscera
ii)Abdonminalaortasupplyingwallofabdominalcavityanditsviscera.
Right andleft common carotid arteriesdivide into -
a) Internalcarotid artery b)Externalcarotidarteryonrightandleft sides.
Branches of external Carotid artery
i) Facialartery, supplying face
ii) Maxillaryartery, supplying jaws
iii)Temporalarterysupplying temporalpartsin skull.
iv) Occipitalarterysupplying occipitalpartsinskull.
Branches of Internal CarotidArtery
i)Anterior cerebralarterysupplying brain
ii) Middle cerebralarterysupplying brain &
iii) Opthalmicartery, supplying eyes.
Circle of willis : Circle ofwillis is formed bycerebralarteries and branch
ofvertebralartery. Branch ofvertebralarteryis also called basilar artery.
Right and left sub clavian arteries, their course and branches :
- Subclavianarteryafter entering axilla continuesas axillaryartery.
- It becomes brachialarteryat lower boundaryofaxilla.

Fig 5.3Arteries of Human Body
- It runs down the armand divides into
(a) Radialartery (b) Ulnar artery
- Palmar archis formed byunionofthese two arteries in the palm
- Palmar archdivides into digitalarteries, whichsupplyfingers.
Course ofthoracicaorta: Desencending aorta continues as thoracic aorta
above diaphragm.
- It, then continues as abdominalaorta below diaphragm.
Branches ofabdominal aorta.
Theyare
(i) Coeliac plexus
(ii) Mesenteric arteries

iii) Renalarteries
iv) Finalbranches
Coeliac plexusdivides into-
i) Hepatic artery- supplying liver
ii) Gastric artery- supplying stomach
iii) Splenic artery- supplying spleen.
Mesenteric arteries are -
i) Superior mesenteric artery
ii) Inferiormesenteric artery
Renalarteriessupplykidney.
Final branches are -
i) Right commoniliacartery ii) Left commoniliac artery
These commoniliac arteries divide into -
i) Internaliliac artery- suplyingpelvic organs. Infemales, itsbranchuterine
arterysupplies uterus.
ii) Externaliliac artery-
Continueing inthighasfemoralartery.
Continueing inpoplietealfossa as polietealartery.
It divides inleg into -
a)Anterior tibialartery- giving rise to dorsalis pedis artery.
b) Posterior tibialartery- giving rise to plantar artery
Plantar archis formed byunionofdorsalis pedis andplantar artery. Plantar
archdividesinto digitalbranches supplyingthe toes.
5.4.2 Veins of the body
Allthe veinsofthe bodyjoinsuperior and inferior venacavaeand drainthe
collected blood into right atriumofheart.
Superior venacava: Superior venacava isformed byunionofright and left
brachiocephalic veins collecting blood fromhead, neck, upper extremities and
some part ofthorax.

Inferior venacava : Inferior venacava is formed byunion oftwo common
iliac veins collecting blood from lower extremities and abdomen. It extends
upwards through abdomenand thorax and opensinto right atrium.
Veins ofthe head, neck and upper limbs :
Internal and external jugular veins drain head and neck. They join with
subclavianveinsforming brachiocephalic veins. Subclavianveins collect blood
fromupper limbs. Subclavianveinis axillaryvein inaxilla. It isformed byunion
ofbrachial, cephalic and basilic veins ofupper arm. Radialand ulnar veins of
fore arms join with those of upper arms. Radial viens collect blood from
metacarpals. Ulnarveincollects fromfingersthroughpalmar arch.
Fig 5.4Veins of Human Body
Veins ofabdomenand lower limbs : Poplietalvein is formed byunion of
anterior and posterior tibialveins ofleg. It continues as femoralvein. Femoral
vein continues as externaliliac vein. Externaliliac vein joins with internaliliac
vein and forms common iliac vein. Commoniliac veins ofbothsides unite and
forminferiorvenacava.Commmoniliacveincollectsbloodfromlowerextremities

and abdomen. In abdominal region, renal veins from kidneys, gonadal veins
from testes or ovaries, suprarenal veins from suprarenalglands, hapatic vein
fromliver, lumbar veins fromabdominalwallandinternaliliacveins joininferior
venacava. Internaliliac or hypogastric veins drain blod from glutealmuscles,
medialside ofthigh, urinary bladder, prostate gland, vas-deferens, uterus and
vagina.
5.5 Types of Circulation
There are mainlytwo circulatorynetworks inthe body. Theyare
1) Systemic circulationor greater circulation
2) Pulmonarycirculationor lesser circulation
Systemic circulation : Oxygenated blood is circulated to allthe parts of
bodyfromthe left ventricle ofheart throughAORTA. Deoxygenatedblood of
all parts of body reaches right artium of heart through SUPERIOR and
INFERIORVENACAVAE. This is themajor circulatorynetwork ofbodyand
called systemic circulationor greater circulation.
Pulmonarycirculation : Deoxygenated blood reachingright atriumgoes
into right ventricle and from here, it reaches lungs throughpulmonary artery.
After losing CO2 inlungs, it gets oxygenated and reaches left artiumof heart
through PUMONARY VEINS. It is called pulmonary circulation or lesser
circulation.
Fig 5.5Types of Circulation
Coronarycirculation: Coronarycirculationis the circulation ofblood in
the blood vessels ofthe heart muscle ( myocardium). The vessels that deliver
oxygen-rich blood to the myocardium are known as coronary arteries. The

vessels that remove the deoxygenated blood fromthe heart muscle are known
as cardiac veins.
Fig 5.6 Coronary Circulation
Thecoronaryarteriesthat runonthesurfaceoftheheartarecalledepicardial
coronaryarteries. The coronaryarteries that run deep within the myocardium
are referred to as subendocardial. The coronary arteries are classified as "end
circulation", since they represent the only source of blood supply to the
myocardium: thereis verylittle redundant blood supply, whichiswhyblockage
ofthese vessels can be so critical.Right and left coronaryarteries arising from
ascending aorta supplyoxygenated blood to heart. Coronaryveins collecting
deoxygenated blood fromheart join coronarysinus, whichopens into inferior
venacava.
Portalcirculation: It is the circulatorynetwork through liver. Portalvein
and hepatic arterybringblood to liver.Portalveincarriesbloodinto liverthrough
superior mesenteric and splenic veins. Superior mesenteric vein carries blood
from mesenteric bed (stomach, small intestine, part of large intestine and
pancreas). Splenic veincarries fromspleeen. Hepaticarterycarries oxygenated
blood to liver. Capillaries ofportalvein join with capillaries of hepatic artery.
Hepatic vein carries blood circulated in liver to right atriumof heart through
inferior venacava. Thiscirculatorynetwork ofliver iscalled portalcirculation.
Conclusion
Cardio vascular system consists ofheart and blood vessels of body.
Greater circulation&Lesser circulation are important circulationsystems
ofbody

Summary
Cardio vascular systemconsists ofheart andvascular system. Heart
contains four chambers. Upper two chambers are called atria or auricles and
lowertwo chambersarecalledventricles. Histologyofheart showspericardium,
myocardium and endocardium. Conducting system ofheart consists ofS.A.
node,A.V. node, bundle ofHis, branches ofbundle ofHis and purkinje fibres.
Vascular systemconsists ofarteries, arterioles, capillaries, venules and veins.
Arteries and veins containthree layers-tunica externa, tunica mediaand tunica
interna.Aorta is the main arteryofthe body. Superior and inferior venacavae
are themainveins ofbody. Veins ofsuperior partsofbody, upper partsoflimbs
and some parts ofthorax joinsuperior venacava. Veins ofabdomen and lower
limbsjoininferiorvenacava. Different circulatorynetworksofbodyare-systemic
circulation, pulmonarycirculation, coronarycirculation, portalcirculationetc.
Model Questions
1. Name the chambers of Heart.
2. What are the layers ofheart?
3. Mention the valves ofheart.
4. What are the blood vessels attached to heart?
5. Write about ductus arteriosus.
6. Explainnerve supplyto heart.
7. List theconducting tissues ofheart.
8. Where is S.A. node located?
9. DescribeA.V. node.
10. What is bundle ofHis?
11. Name the layers ofArteries and Veins.
12. What are the parts ofAorta?
13. Write the branches ofarch of aorta.
14. What are the branches ofascending aorta?
15. Name the divisions ofdescending aorta.

16. Write the branches ofexternalcarotid artery.
17. List the branches ofinternalcarotid artery.
18. What is palmar arch?
19. Name the arteries of upper limbs.
20. What is the course ofthracic aorta?
21. Mention the branches ofbdominalaorta.
22. Write thedivisions ofcoeliac plexus.
23. What are mesenteric arteries?
24. What is plantar arch?
25. What are main veins ofbody?
26. Name the veins of head and neck.
27. Mention the names and course ofveins ofupper limbs.
28. Write the veins oflower limbs.
29. Mentionabdominalveins.
30. What is systemic circulation?
31. Writeabout pulmonarycirculation.
32. Explainportalcirculatorynetwork.
33. Describe coronarycirculation.
1. Explainthe anatomyofheart with figure.
2. Writeabout the histologyofarteries and veins. Discussarteries ofbody.
3. DiscussVeins ofbody.
4. Discuss the types ofcirculationofbody.
.

UNIT
Lymphatic System
6
Structure
6.1Introduction
6.2 Spleen
6.3Tonsils
6.4 Thymus
Learning Objectives
• Student shouldknow the anatomyoflymphatic system.
• Student shouldknow different lymphoid tissues inthe body.
6.1 Introduction
Lymphatic systemisa closed systemconsisting of1. Lymphatic capillaries
2. Lymphatic vessels 3. Lymph nodes and 4. Lymphducts.
6.1.1 Lymphatic capillaries
Theyare fine hair like vessels withporous walls. Theyaraise in the tissue
spaces. They unite to form lymphatic vessels. Walls of the capillaries have
permeability to substances of greater molecular size than the substances
permeablethroughwallsofbloodcapillaries.Theirwallsareformedbyendothelial
cells and supported byfibrous connective tissues.

Fig6.1 Lymphatic System
6.1.2 Lymphatic Vessels
Lymphatic capillaries unite to formlymph vessels. Theyhave one sided
valves. Theyaresuperficiallyanddeeplylocated. Theyare foundinskin, muscles
and several visceralorgans. Various lymphatic vessels are linked together by
free anastamoses. Lymph vessels pass through lymph nodes. They gradually
increaseinsize.Finally lymphcollectedfromthebodypoursinto right lymphatic
duct and left lymphatic duct. Left lymphaticduct is also calledas thoracic duct.
6.1.3 Lymph Nodes
Lymphnodesare smallbodies madeoflyumphatic tissue. Theyvaryinsize
frompinhead to almond. Theyare important glandular structuresspread at all
strategic points in the body. They are located both superficially and deeply.
Lymphatic vesselsbring lymphto lymphnodes. Theydividewithinthe nodeand
discharge lymph. Againlymph is gathered into fresh lymphatic vessels which
emptylymphinto lymphatic ducts aftercarryingthe lymphthroughmore lymph
nodes. Lymphaticvessels entering into thelymphnode are calledafferent lymph
vessels. Lymph vessels leaving the lymph nodes are called as efferent lymph
vessels.

Fig6.2L.S. ofLymphnode
HistologyofLymphnode:Histologyoflymphnodeshowsthreeparts.They
are-Cortex,medulla&hilum.
1. Cortex: Cortexis the outer part of lymph node. It contsins lymphatic
nodules peripherallyand germinalcentres in the inner zone, Germinal centres
present inthelymphnodesproducelymphocytes. Lymphsinusesseparatelymph
nodules fromcapsule.
2. Medulla : It is the inner part of lymph node. It is devoid of lymph
nodules. It contains reticulo endo thelialcells. It also contains a few giant cells.
3. Hilum : It is the depression at one side of lymphnode or lymph gland.
ThroughHilum,anarteryentersandthereisexit toaveinandanefferent lymphatic
vessel.Afferentlymphvesselsenterfromallsides but eferentlymphvesselleaves
through hilum Chief efferent vessel leaving lymph node carries filtered and
lymphocyte enrichedlymphfluid.
Naming oflymphnodes: Lymph nodes are named accordinglyas theyare
located.Theyare-
(a) Cubitaland axillarylymphnodes:Theyaresituated inarms.
(b) Poplietaland inguinal: Lymphnodes situated inlegs are named so.
(c) Submaxillaryandcervicallymphnodes:Lymph nodespresent inthe
neck are called as submaxillaryand cervicallymphnodes.
(d) Mediastinallymph nodes: These are present inThorax.
(e)Abdominallymphnodes:Theyare present inabdomen. ex:Mesenteries
(f) Pelvic lymph nodes: Pelvic lymphnodes are present inpelvic organs.
Capsule
Sinus
Cortex
Hilum
Afferent Lymphatic Vessel
Efferent Lymphatic Vessel
Valve to prevent backflow

6.1.4 Lymph Ducts
Efferent lymphvesselsleavinglymphnodes pour lymphinto right lymphatic
duct and left lymphatic duct (thoracic duct). Thoracic duct is comparatively
largerthanright lymphaticduct. Itbeginsat cisternachyli. Cisternachyliis asmall
pouch at the back of the abdomen. Lymphatic vessels from lower limbs,
abdominalandpelvicorgans emptyinto thispouch.Fromcysternachyli, thoracic
duct runsupthroughmediastinumbehind theheart to theroot ofthe neck. Here,
it turnsto the left wherelymphatic vessels fromtheleft side ofhead, thoraxand
left upper limp join. Thoracic duct finalyempties into left sub clavianvein at its
junction withleft internaljugular vein. It is provided withunidirectionalvalves
to prevent lymph from flowing in wrong direction. Right lymphatic duct is
comparativelysmaller. It is formed byjoining of lymphatic vessels fromright
side ofhead, thoraxand right upper limbat the root ofneck. It enters into right
subclavian vein, where it joins right internaljugular vein. Lymphatic ducts thus
gather lymphfromalthe bodyand return it to blood stream.
6.2 Spleen
Spleen is the largest lymphoid tissue in the body. It is a bean shaped,fist
sized organ. It is a highlyvascularorgan. It is located inthe left hypochondrium
beneath the diaphragm. It is above the left kidney and descending colon and
behind the stomach. It weighs about 150 g. in adult human beingand does not
containafferent lymphaticvessels.It is haemopoietic.
Fig 6.3 T.S. of Spleen
SPLEEN(follicle), stainedwithhaematoxylinandeosin-lymphoid follicle,
circledwithdottedline shows-
1 - Germinalcenter ofthe follicle 2 - Mantie zone ofthe follicle

3 - Marginalzone of the follicle 4 - Periarterial area ofthe follicle
5 - Central arteriole 6- Red pulp 7 - Trabeculae
Splenic pulp: Splenic pulp isthe parenchymaltissue withinthe capsule. It
istwo types 1) White pulp 2) Red pulp.
Splenic sinuses:Splenic sinuses are long vascular channels. Theyare 35 to
40  diameter.
Splenic cords: Theyare continuous partitions inbetweensplenic sinuses.
Marginalzone: It is the junctionalzone between white pulpand red pulp.
6.3 Tonsils
Tonsils are well-defined organs of accumulated lymphoid tissue in the
mucous membraneat the root oftongue. Tonsils are present at the surrounding
ofpharynx, where nasaland oralpassages unite. Tonsils do not possess afferent
lymphaticvessels.
Tonsils canbedivided into three groups.
1) Palantinetonsils -covered bystratifiedsquamous epithelium
2) Lingualtonsil- situated at theroot oftongue.
3) Pharyngeal tonsils - one on each side in the median posterior wall of
nasopharynx.
6.4 Thymus
Thymusispartlyendocrineglandandpartlylymphoidstructure. Itis present
inanteriorand superior mediastinumofthorax. It extends frompericardiumup
into neck. It consists oftwo lobes.
Histologyofthymus shows -
1) Capsule 2) Cortex&3) Medulla
Conc.lusion
Lymphaticsystemis a closedsystemconsistingof1)Lymphatic capillaries
2)Lymphatic vessels 3) Lymph nodes and 4) Lymphducts.
Summary
Lymphatic systemis a closed systemconsisting oflymphatic capillaries,
lymphaticvessels,lymphnodesandlymphducts. Histologyoflymphnodeshows
three parts. They are -Cortex,medulla&hilum.Spleen, tonsils and thymus are

also lymphatictissues.Spleenishaemopoieticorgan. Splenicpulpisparenchymal
tissue with inthe capsule ofspleen.
Model Questions
1. Definelymphatic system.
2. Explainlymphatic capillaries.
3. Describe lymphatic vessels.
4. What are (a) Cubitaland axillarylymph nodes.
(b) Mediastinallymph nodes.
5. Mentionthe histologicalparts oflymph node.
6. Name the lymphducts.
7. Write thehistologyofspleen.
8. What is splenic pulp?
9. Define splenic sinuses.
10. Writethe definitionoftonsils.
11. Mentionthe parts inthe histologyofThymus.
1. Write the anatomyoflymphatic system.

UNIT
Bones and Joints
7
Structures
7.1Introduction
7.2 CompositionofBone
7.3 Ossification
7.4 Types of Bones
7.5 Bones ofthe Human Body
7.6 Joints
Summary
Learning Activities
• Student should know allthe bones ofhumanbody.
• Student should knowabout the joints.
7.1 Introduction
Bones and Joints form the skeletalsystem of body.There are about 206
bones in humanbody. Main functions ofskeletalsystemare -
1. Giving support and protectionto soft tissues and vitalorgans.
2. Giving attachment to muscles and assisting inbodymovements.

3. Formation ofblood cells in the red bone marrow.
4. Storageofmineralsalts like calciumand phosphorous.
Fig 7.1 Skeletal System
7.2 Composition of Bone
Bone is structurallya complexorgan and hasthe following composition.
water - 25%
Ossein,Osseomucoid and OsseoAlbumin (organic solids) - 35%
inorganic saltsofcalcium - 45%
Calciumsalts impart hardness to bones.
Structure ofbone tissue: Refer to Celland Tissues.
Functions ofbone marrow :
Bone marrow performsfunctions of-
1) Formationofblood cells(Haemopoeisis)
2) Destructionofold RBC withthe helpofreticulo endothelial
cells(haemolysis)
3)Protectionofbodyagainst infectionsbymicrobes withthehelpofreticulo
endothelialcells against foreignparticles(Defencemechanism)
4)Against foreignparticles(Defence mechanism)

7.3 Ossification
Ossificationis the process ofbone formation. Development ofbonestakes
place from spindle shaped cells called osteoblasts.There are two types of
ossification. Theyare-
1) Intramembranous ossification.
2) Intracartilaginous ossification.
1. Intra membranous ossification : Type ofossificationinwhich, dense
connective tissue is replaced bydeposits ofcalcium, forming bone is called as
intramembranous ossification.
Ex: Bonesofskullare formed bythis process.
2. Intra cartilaginous ossification : Type of ossification in which,
cartilages are replacedbybone is called asintracartilaginous ossification. Most
ofthe bones of the bodyare formed bythis process.
7.4 Types of Bones
Bones are mainlythree types. Theyare- 1) Long bones. 2)Short bones 3)
Flat bones 4) Irregular bones 5) Seasmoid bones.
1. Long bones: Long bones are found in limbs. A long bone has two
ends. Ends ofa long bone arecalledas epiphyses. Thesetwoendsare connected
byshaft,whichiscalledasdiaphysis. Periosteumistheouter membranecovering
the bone. Periosteumis followed bylayer ofcompact bone. Centralmedullary
canalisinside this.
Fig 7.2 Long bones

Throughnutrient foramen, arteries enter. Medullarycanalcontains yellow
bone marrow. Extremities consist ofmass ofspongybone, whichcontains red
bone marrow.Yellowbone marrow contains fat and blood cells but isnot richin
blood supplyor red blood cells. Long bones develop fromthree centres called
centres ofossification. Centre ofossificationpresent inshaft iscalled diaphysis
and centres ofossificationpresent at theends ofthe bonesare called epiphyses.
Line ofcartilagebetween epiphysis and diaphysis is called epiphysealcartilage
or epiphyseal plate.Epiphyseal plate separates epiphysis and diaphysis
approximatelyupto25yearsofage.Afterthisage,fusionofdiaphysisandepiphysis
takes place.After fusion,growth in length of bone becomes
impossible.Acromegalyis growthofbone occurings after fusion ofdiaphysis
and epiphysisbythe overactivityofgrowthhormone.It willbeconfined mostly
to the bones of face and limbs.This growth will be abnormal. Gigantism is
growth occuring in immature bones before fusion ofdiaphysis with epiphysis
due to excessivesecreion ofgrowthhormone.
2. Short bones : Short bones do not have shaft. They contain spongy
substance coveredbyshellofcompact bone.ex: smallbones ofwrist and ankle.
3. Flat bones : They contain two layers of compact bone with spongy
substance betweenthe two layers. Theyare found in pelvis and scapula.
4. Irregularbones:Boneswhichdo not fallinto anycategoryare irregular
bones. ex: vertebrae and bones of face.
5. Seasmoid bones : They are small bones and develop in tendons of
muscles. ex: Patella ofknee joint.
7.5 Bones of the Human Body
Total206 bonesforming the humanskeletoncanbedividedinto (1)Bones
of Axial skeleton:
(i) Bones of skull: Bones of cranium
Bones of face
(ii) Bones of trunk:Sternum
Ribs
Vertebral column
(2) Bones of appendicular skeleton:
Bones of upper limbs
Bones of lower limbs

7.5.1 Bones of Axial Skeleton
7.5.1.1 Bones of skull
Skullisalargebonystructurecontainingcraniumandbonesoffaceattached
to cranium.
Bones of Cranium : Craniumis called as brain box. It is a large, hollow
bonycase. Itis formed byfusionofvarious bones withzigzagedges. Craniumis
formed by 8 bones. They are -
1. Frontal bone-1
2. Parietalbones-2
3. Temporalbones-2
4. Occipitalbone-1
5. Sphenoid bone-1
6. Ethmoid bone-1
Fig 7.3 Bones of Skull
Sutures ofthe Cranium
Immovable jointsofbones ofskullare called sutures. Important sutures of
craniumare- (1)CoronalSuture (2) Sagitalsuture & (3) Lambdoid suture
Coronal suture : Coronalsuture is the immovable joint between frontal
bone and parietal bones.
Sagital suture : Sagital suture is the immovable joint between the two
parietalbones.
Lambdoid suture : Lambdoid suture is the immovable joint between
occipitalbone and parietalbones.
Frontal bone : It isinthe front centralportionofcranium. It is joined with
two parietalbones. It extends upto foreheadand forms roofoforbitaland nasal
cavities.
Features offrontal bone : It has the following features. Theyare-
(1) Supra orbitalmargins- forming thearches oforbit.
(2) Nasalnotch- It is the bone projecting between supraorbitalmargins.
Pareital bone
Lacrimal bone
Temporil bone
Maxilla
Occipital bone
Mandible
Zygomtic bone
Ethomoid bone
Nasal bone
Frontal bone

Nasalbones are fitted to this.
3) Super ciliaryarch - It lies above these two structures.
4) Frontaltuberosities are the two prominences offorehead.
Fig 7.4 Frontal Bone
Parietal bones
Parietalbones aretwo innumber. Theyformthe roofand sidesofthe skull.
Theyare ofquadrilateralshape. Prominence ofparietalbone is called parietal
tuberosity. Inner surface of parietal bone is concave. Superior and inferior
temporallinesrunparallally.
Aparietalbonehas joint with:
- frontalbone anteriorly.
- occipitalbone posteriorly.
- other parietalbone mediallyand
- temporalbone inferiorly
Fig 7.5 Parietal Bone
Pareital tuberosity
Inferior Temporal line
Superior Temporal line

Temporal Bones
Temporalbones aretwo in number. Theyformlower part ofsides ofskull.
Temporalboneshave joint with:
-sphenoid bone inthe front
-parietalbones above.
-occipitalbone behind.
Fig 7.6 Temporal Bone
Atemporalbonehas the following parts.
a) Squamous part : It is flat part having zygomatic process.
b) Petrous part : It forms the bone ofinternalear.
c) Mastoid part : It contains mastoid process.
d)Tympanicpart : It containsexternalauditorymeatus.
Occipital Bone
Fig 7.7 Occipital Bone

Features ofoccipitalbone :Anoccipitalbone has the following features.
(a) External occipital protruberance: It is a prominance of occipital
bone. It givesattachment to muscles.
(b) Foramen magnum : It is a large oval opening below the external
occipitalprotruberance.Cranialcavitycommunicateswithvertebralcanalthrough
thisopening.
(c) Occipital condyles: They are two in number. They lie one on each
side offoramen magnum. Theyarticulate with atlas. This joint allows nodding
movement ofhead.
Sphenoid Bone
It is one innumber. It is situated at thebase ofthe skullinfront oftemporal
bones. It forms large part ofmiddle cranialfossa. It is shaped like a Figat with
outstretching.
Fig 7.8 Sphenoid Bone
a. Body : Bodycontains two large air sinuses. They communicate with
nasalcavity. Bodyalso has a deep depressioncalled hypophysealfossa, which
contains pituitarygland. Hypophysealfossa is also called as sella turica.
b. Wings: These wing likestructures are called greaterand lesser wings.
Theyhave manyopenings for passage ofnerves and blood vessels.
Ethmoid bone: It is one innumber. It is cubicalin shape. It fills the space
between orbits. Ethmoid bone consists ofthree parts. Theyare -
(a) Cribriformplate
(b) Perpendicular plate
(c) Labyrinths (2)

Fig 7.9 EthmoidBone
Cribriformplate is a smallhorizontalplate perforated with number offine
openings throughwhichbranches ofolfactorynerve pass fromnoseto thebrain.
Perpendicular platedescends fromcribriformplate. It forms upper part ofnasal
septum. Two labyrinths each consisting ofa number ofethmoidalsinuses are
thinwalled andcommunicate withnasalcavity.
Superior and middlenasalconchae are thinplatesofethmoid bone.Inferior
nasalconchaeare curved plates ofbone whichlie inthe walls ofthenasalcavity
below superior and middle nasalconchaeofethmoid bone.
Cranial Fossae
Base ofthe skullis divided into three fossae.
Theyare-
1.Anteriorcranialfossa
2. Middle cranialfossa.
3. Posterior cranialfossa
Fig 7.10 Cranial Fossae
Anterior cranialfossa isformed byhorizontalplates offrontalbone. Middle
cranialfossais formed bysphenoidbone and petrousportionoftemporalbones.
Posterior cranialfossa is formed byoccipitalbone.
Anterior Cranial Fossa
Middle Cranial Fossa
Posterior Cranial Fossa

Fontanelles
Due to incomplete ossificationofskullbones ofchild at birth, membranes
fillthe spacebetweenbones. These membranesat the angles ofbones are called
fontanelles. Theyare -
1.Anterior fontanelle.
2. Posterior fontanelle.
Fig 7.11 Fontanelles
Anteriorfontanelle : It is the largest fontanelle present at the junction of
frontaland two parietalbones where coronaland sagitalsuturesmeet. It closes
at the age of1½ years.
Posteriorfontanelle: It isthefontanelle present at thejunctionofparietal
bones and occipital bone. It closes as soon as birth takes place.
Sinuses : Sinusesare the cavities inthe bones ofskulland communicating
with nose. Theyare 1) Frontalsinuses 2) Maxillarysinuses 3) Ethmoidaland
sphenoidalsinuses.
Frontal sinuses are a pair of sinuses present in frontal bones. They are
present oneon eachside ofthe root ofthenose. Maxillarysinuses are a pair of
sinuses in maxillary bones- each lying on each side of nose. Ethmoidal and
sphenoidalsinuses arealso present inskull.
Functions of sinuses
Functions ofsinuses are-
1. Lightening ofbones offaceand cranium.
2. Givingresonance to voice.
Bones of the face
Bones making the face are 14 innumber. Theyare-

Maxillae -2 (upper jaw)
Mandible -1 (lower jaw)
Zygomatic bones -2 (cheek bones)
Palate bones -2 (roofof mouth cavityand hard palate)
Lacrimalboness -2
Nasal bones-2 (Nasal bridge)
Turbinate bones-2 (Nasalconchae)
Vomer-1 (Lower part ofnasalseptum)
Maxillae
Theyaretwo innumber.
Theyformupper jaw.
Fig 7.12 Maxilla
Features of Maxillae
1. Bodyis pyramidalin shape.
2. Zygomaticprocess, palatine process, alveolarprocess&frontalprocess
are present.Alveolar process contains upper teeth.
3. Maxillarysinus is present ininternalaspect.
Mandible : It forms the lower jaw. It is the onlymovable bone ofskull.
Fig7.13 Mandible(left half)

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