4. HODS - November 2006 4
HEART
• Hollow, muscular organ
• 300 grams (size of a fist)
• 4 chambers
• found in chest between lungs
• surrounded by membrane called
Pericardium
• Pericardial space is fluid-filled to nourish
and protect the heart.
5. HODS - November 2006 5
HEART ANATOMY
• The heart is a complex
muscular pump that
maintains blood
pressure and flow
through the lungs and
the rest of the body.
• The heart pumps about
100,000 times and
moves 7200 liters
(1900 gallons) of blood
every day.
6. HODS - November 2006 6
HEART ANATOMY
The heart has four chambers.
Two atria act as collecting
reservoirs.
Two ventricles act as pumps.
The heart has four valves for:
Pumping action of the heart.
Maintaining unidirectional
blood flow.
7. HODS - November 2006 7
Functions of the Heart
• Generates blood pressure
• Routes blood
– Heart separates pulmonary and systemic
circulation
• Ensures one-way blood flow
– Heart valves ensure one-way flow
8. HODS - November 2006 8
Functions of the Heart
• Regulates blood supply
– Changes in contraction rate and force
match blood delivery to changing metabolic
needs
– Most healthy people can increase cardiac
output by 300–500%
• Heart failure is the inability of the heart
to provide enough blood flow to
maintain normal metabolism
9. HODS - November 2006 9
Cardiac Cycle
• The heart is two pumps that work
together, right (pulmonary) and left
(systemic) half
• Repetitive, sequential contraction
(systole) and relaxation (diastole) of
heart chambers
• Blood moves through circulatory system
from areas of higher to lower pressure.
– Contraction of heart produces the pressure
11. HODS - November 2006 11
HEART
Deoxygenated blood returns
to the heart via the superior
and inferior vena cava,
enters the right atrium,
passes into the right
ventricle, and from here it is
ejected to the pulmonary
artery.
Oxygenated blood returning
from the lungs enters the left
atrium via the pulmonary
veins, passes into the left
ventricle, and is then ejected
to the aorta.
12. HODS - November 2006 12
Blood Vessels
• Blood vessels are divided into a pulmonary
circuit and systemic circuit.
• Artery - vessel that carries blood away from
the heart. Usually oxygenated
• Vein - vessel that carries blood towards the
heart. Usually deoxygenated.
• Capillary - a small blood vessel that allow
diffusion of gases, nutrients and wastes
between plasma and interstitial fluid.
13. HODS - November 2006 13
Blood Vessels
• Systemic vessels
– Transport blood through the body part from
left ventricle and back to right atrium
• Pulmonary vessels
– Transport blood from right ventricle through
lungs and back to left atrium
• Blood vessels and heart are regulated to
ensure blood pressure is high enough for
blood flow to meet metabolic needs of tissues
15. HODS - November 2006 15
LUNGS
• Lungs comprised of
– Airways
– Alveoli
http://www.aduk.org.uk/gfx/lungs.jpg
16. HODS - November 2006 16
What do the lungs do?
• Primary function is gas exchange
• Let oxygen move in
• Let carbon dioxide move out
17. HODS - November 2006 17
How do the lungs do this?
• First, air has to move to the region
where gas exchange occurs.
• For this, you need a normal ribcage and
respiratory muscles that work properly
(among other things).
18. HODS - November 2006 18
Conducting Airways
• Air travels via laminar
flow through the
conducting airways
comprised of the
following: trachea,
lobar bronchi,
segmental bronchi,
subsegmental bronchi,
small bronchi,
bronchioles, and
terminal bronchioles.
19. HODS - November 2006 19
How do the lungs do this?
• The airways then branch further to
become transitional/respiratory
bronchioles.
• The transitional/respiratory zones are
made up of respiratory bronchioles,
alveolar ducts, and alveoli.
20. HODS - November 2006 20
Weibel ER: Morphometry of the Human
Lung. Berlin and New York: Springer-
Verlag, 1963
The Airways
• Conducting zone: no
gas exchange occurs
– Anatomic dead
space
• Transitional zone:
alveoli appear, but are
not great in number
• Respiratory zone:
contain the alveolar
sacs
• Over 8 million branches
21. HODS - November 2006 21
How does gas exchange
occur?
• Numerous capillaries are wrapped
around alveoli.
• Gas diffuses across this alveolar-
capillary barrier.
• This barrier is as thin as 0.3 μm in some
places and has a surface area of 50-
100 square meters!
22. HODS - November 2006 22
Gas Exchange
• Diffusion Barrier crossed by O2 moving
from air to blood and CO2 from blood to
air is made up of:
• 1. an aqueous surface film
• 2. epithelial cells of alveolus
• 3. interstitial layer
• 4. endothelial cells of capillaries
• 5. blood plasma
• 6. membrane of RBCs
23. HODS - November 2006 23
Alveoli
• Approximately 300
million alveoli
• 1/3 mm diameter
• Total surface area
about 85 sq. meters
(size of a tennis
court)
24. HODS - November 2006 24
Gas Exchange
From
Netter
Atlas of
Human
Anatomy,
1989
25. HODS - November 2006 25
Control of Ventilation
• Arterial PO2
– When PO2 is VERY low, ventilation increases
• Arterial PCO2
– The most important regulator of ventilation, small
increases in PCO2, greatly increases ventilation
• Arterial pH
– As hydrogen ions increase, alveolar ventilation
increases, but hydrogen ions cannot diffuse into
CSF as well as CO2
27. HODS - November 2006 27
Anatomy of the Pancreas
• 5" long by 1" thick
• Head close to curve in C-
shaped duodenum
• Main duct joins common
bile duct from liver
• Sphincter of Oddi on
major duodenal papilla
• Opens 4" below pyloric
sphincter
28. HODS - November 2006 28
Gray’s Anatomy of the Human Body
Anatomy of the Pancreas
29. HODS - November 2006 29
Gray’s Anatomy of the Human Body
Robbins Basic Pathology
http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/default.htm
Digestive gland that secretes digestive enzymes
into the duodenum through the pancreatic duct.
Exocrine glands have ducts that carry their secretions to specific locations.
Anatomy of the Pancreas
31. HODS - November 2006 31
Histology of the Pancreas
• Acini- dark clusters
– 99% of gland
– produce pancreatic
juice
• Islets of Langerhans
– 1% of gland
– pale staining cells
– produce hormones
36. HODS - November 2006 36
LIVER
• Largest gland in the body (1.4 kg – 3 lbs.)
• Produces bile
– Stored in GB
– Emulsifies fats
• Involved in metabolism
• Diaphramatic and visceral surface
• Right and left lobes
• Porta hepatis = major vessels and nerves
• Right and left hepatic ducts, common bile,
common
37. HODS - November 2006 37
Histology of the Liver
• Hepatocytes arranged in lobules
• Sinusoids in between
hepatocytes are blood-filled
spaces
• Kupffer cells phagocytize
microbes & foreign matter
40. HODS - November 2006 40
Functions of the Liver
• Bile production
– Salts emulsify fats, contain pigments as bilirubin
• Storage
– Glycogen, fat, vitamins, copper and iron
• Nutrient interconversion
• Detoxification
– Hepatocytes remove ammonia and convert to urea
• Phagocytosis
– Kupffer cells phagocytize worn-out and dying red and white
blood cells, some bacteria
• Synthesis
– Albumins, fibrinogen, globulins, heparin, clotting factors
41. HODS - November 2006 41
Bile
• About 600 ml of bile is produced daily
– Bile acid
– Phospholipids
– Cholesterol
– Bilirubin
– Waste products
– Electrolytes
– Mucin
43. HODS - November 2006 43
KIDNEYS
• Play a major role in maintaining homeostasis
• Maintain water balance
• Regulate the quantity and concentration of
ECF ions
• Regulate the plasma volume
• Regulate pH by controlling elimination of acid
and base in urine
• Maintain osmolarity
• Regulate the concentration of plasma
constituents (e.g. electrolytes and water)
44. HODS - November 2006 44
KIDNEYS
• Kidneys have excellent blood supply: 0.5% total
body weight but ~20% of Cardiac Output.
• Kidneys process plasma portion of blood by
removing substances from it, and in a few cases,
by adding substances to it.
• Works with cardiovascular system (and others!)
in integrated manner
45. HODS - November 2006 45
Functions of the kidneys
• Regulation of H2O and inorganic ion balance – most
important function!
• Removal of metabolic waste products from blood and
excretion in urine.
• Removal of foreign chemicals in the blood (e.g.
drugs) and excretion in urine.
• Gluconeogenesis
• Endocrine functions (e.g. renin, erythropoetin, 1,25-
dihydroxyvitamin D)
• In kidney disease, build-up of waste serious, but not
a bad as ECF volume and composition disturbances.
46. HODS - November 2006 46
Functions of the kidneys
• Water balance
• Electrolyte balance
• Plasma volume
• Acid-base balance
• Osmolarity balance
• Excretion
• Hormone secretion
47. HODS - November 2006 47
Acid-Base Balance
• Kidneys VERY important for acid-base balance, along
with respiratory system.
• Important because all biochemical processes must occur
within an optimal pH window.
• Prevent ACIDOSIS or ALKALOSIS.
• Although the lungs excrete a large amount of CO2, a
potential acid formed by metabolism, the kidneys are
crucial for excreting non-volatile acids.
• To maintain acid-base balance, kidney must not only
reabsorb virtually all filtered HCO3
-, but must also
secrete into the urine the daily production of non-volatile
acids.
49. HODS - November 2006 49
Internal Anatomy of
Kidneys
• Cortex: Outer area
– Renal columns
• Medulla: Inner area
– Renal pyramids
• Calyces
– Major: Converge to form
pelvis
– Minor: Papillae extend
• Nephron: Functional
unit of kidney
– Juxtamedullary
– Cortical
50. HODS - November 2006 50
Kidney Failure
• at age 49 years, the expected duration
of life of a patient with end-stage renal
disease on hemodialysis is 7 additional
years compared with approximately 30
additional years for a person of the
same age from the general population.
51. HODS - November 2006 51
Dialysis and Transplant
Peritoneal
dialysis
Hemo-
dialysis
53. HODS - November 2006 53
SKIN
• Largest organ of the body.
• Surface area 1.5 - 2 m2.
• Average adult weight 9 kg.
• Functions - protection, defence,
sensation, thermoregulation, vit D
synthesis, excretion, storage.
54. HODS - November 2006 54
SKIN
2 Principal portions
• Epidermis - epithelium
• Dermis – areolar &
dense irregular
connective tissue
• Hypodermis
– “beneath the dermis”
– the subcutaneous layer
next to:
• adipose layer or
• muscle or
• bone
55. HODS - November 2006 55
Functions of the Skin
• Protection
– Prevents invasion of environmental toxins and microorganisms
• Immunologic
– Sebum has antibacterial properties which helps shed topical
bacteria
• Thermoregulation
– Insulates from heat loss and controls loss of heat through
evaporation
56. HODS - November 2006 56
Functions of the Skin
• Fluid and Electrolyte Balance
– Controls sodium excretion
– Sebum retards fluid loss from skin
• Metabolism
– Produces Vitamin D
– Prevents excessive fluid loss
• Neurosensory
– Nerve endings and receptors process environmental stimuli for pain,
touch, heat and cold
• Social and Interactive
– Provides body image and personal identity
57. HODS - November 2006 57
Epidermis
• Provides barrier function.
• Multilayered structure, continually
regenerating.
• Thickness dependent on exposure to friction.
• Stratified squamous epithelium, organised in
five layers.
– Stratum basale; Stratum spinosum, Stratum
granulosum, Stratum lucidum, Stratum corneum.
58. HODS - November 2006 58
Epidermis
• First layer of defense
• Composed of dead, keratinized
cells and surrounded by a lipid
monolayer
• There are no blood vessels. It is
fed by capillaries in the dermis.
• If the epidermis is destroyed but
the appendages of the dermis
remain, a new epidermis is
formed when the epithelial grow
out of the hair follicles.
59. HODS - November 2006 59
• EPIDERMIS
• 4 cell types
– Keratinocytes - 90%
• filled with keratin (protein)
• waterproof barrier
– Melanocytes - 8%
• produce melanin (pigment)
• pass melanin to
keratinocytes
– Langerhans cells
• phagocytes (from immune
system)
• easily damaged by UV light
– Merkel cells
• in deepest layer of hairless
skin
• sensory transduction -
touch
61. HODS - November 2006 61
Dermis
• Varies in thickness across body.
• 1 mm on face , 4 mm on back.
• Responsible for most major functions of
the skin.
• Two distinct layers:
Papillary dermis,
Reticular dermis.
62. HODS - November 2006 62
Dermis
• Few cells present - fibroblasts,
macrophages, adipocytes
• Intracellular matrix thick with many
protein fibers: collagen, elastin,
reticular
• The location for blood vessels, nerves
and sensory receptors, glands, hair
follicles
63. HODS - November 2006 63
• Collagen and fibrous connective tissue
• Contains capillaries and arterioles
• Has special sensory nerve fibers and
lymph system
– Meissner Corpuscle: light touch, just
beneath epidermis
– Vater Pacini Corpuscles: pressure
sensors, deep in subq
– Ruffini Corpuscles: heat sensors, deep
in subq tissue
– Krause Corpuscles: cold sensors,
deep in subcutaneous tissue
Dermis
64. HODS - November 2006 64
Dermis
• Papillary region -
outer layer - 20%
– areolar connective
tissue, elastic fibers
– dermal papillae –
mound-like
projections to
increase the
surface area for
nutrition from
capillaries
– some papillae
contain Meissner's
corpuscles (for light
touch)
65. HODS - November 2006 65
Dermis
• Reticular region-
80%
– dense, irregular
connective tissue
– collagen, elastic
fibers in a network
surrounding the
various cells
– fibers give strength,
elasticity,
extensibility
– tears in reticular
region - "stretch
marks“ - long
straight red or white
streaks
67. HODS - November 2006 67
• Connective tissue
• Fat cells in most areas
• Blood vessels
• Nerves
• Base of hair follicles
• Function:
• Insulation
• Storage of nutrients
Subcutaneous Tissue
69. HODS - November 2006 69
Types of Burns
• Superficial
• Superficial partial thickness
• Deep partial thickness
• Full thickness
70. HODS - November 2006 70
Partial Thickness Burn
• Can be superficial or deep
• Involves epidermis and dermis
• Has blister formation
• Moist appearance
• Tactile and pain sensors intact
• Will usually heal on own but will scar
71. HODS - November 2006 71
Full Thickness Burn
• Involves all layer of skin
• Has waxy and dry appearance
• Elasticity destroyed
• Painless
• Does not heal without intervention
– Autologous skin graft or banked skin
