Transcript Functional Organization of the Cardiovascular System

Functional
Organization of the
Cardiovascular System
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Objectives
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Describe the functional organization of cardiovascular
system
List the functions of cardiovascular system.
Describe the main function of arteries, capillaries and
veins
Describe the flow of blood through the chambers of the
heart and through the systemic and pulmonary
circulations.
Compare and contrast the systemic and pulmonary
circulation.
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Functional Organization of
Cardiovascular system
HEART
(PUMP)
CARDIOVASCULAR
SYSTEM
VESSELS
(DISTRIBUTION
SYSTEM)
Blood
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Functions of the Cardiovascular system
System circulates blood throughout the
body.
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Transport of nutrients, oxygen, and hormones to cells throughout
the body and removal of metabolic wastes (carbon dioxide,
nitrogenous wastes, and heat).
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Protection of the body by white blood cells, antibodies, and
complement proteins that circulate in the blood and defend the
body against foreign microbes and toxins. Clotting mechanisms
are also present that protect the body from blood loss after
injuries.

Regulation of body temperature, fluid pH, and water content of
cells.
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THE HEART
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Anatomy of the heart
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Hollow, muscular organ
about the size of a
clenched fist
Positioned between two
bony structures –
sternum and vertebrae
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(CPR)
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Heart: Two sided pump
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Heart: 2 separate pumps (an atrium & a ventricle)
Rightpumps blood through lungs
Left pumps blood through peripheral
circulation
Atrium: weak primer pump for the ventricle
Ventricle: the main pumping force
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Rt. Ventricle
Lt. ventricle
Pulmonary circulation
Systemic circulation
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Blood Flow Through and Pump Action of the Heart
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Pulmonary circulation
Starts at right
ventricle
Ends at left atrium
Receives blood
from right side of
heart
Carries blood
between heart and
lungs
Blood perfusing the
lungs is partially
deoxygenated
systemic circulation
Starts at left ventricle
Ends at right atrium
Receives blood from
left side of heart
Carries blood
between heart and
other organ systems
Blood perfusing the
organ systems is
oxygenated
All blood flows
through lungs
Part of the blood go
to different organ
systems
Low pressure, low
resistance
High pressure, high
resistance
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Heart Valves cont..
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Atrioventricular (AV) valves (Tricuspid & mitral)
 Prevent backflow of blood from ventricles into
atria during ventricular emptying
 Chordae tendinae
 Fibrous cords which prevent valves from
being everted
 Papillary muscles
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Heart Valves cont..
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Semilunar valves (Aortic and pulmonary valves)
 Lie at juncture where major arteries leave ventricles
 Prevented from everting by anatomic structure and
positioning of cusps
No valves between atria and veins
 Reasons
 Atrial pressures usually are not much higher than
venous pressures
 Sites where vecavae enter atria are partially
compressed during atrial contractionnae
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The fibrous skeleton of the heart
Serves 3 roles:
 A mechanical base:
atria anchored above
and ventricles below
 Perforated by 4
apertures, each
containing a valve
 Insulates the
ventricles
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Blood vessels
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Arteries
Structure of arterial wall
 Plentiful of elastic
fibers….high
compliance
Function:
Rapid transit passage-ways
for blood from heart to
tissues
Pressure reservoir
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Arteriole
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Very small artery that delivers blood to capillaries
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Structure
 Very little elastic tissue but thick layer of smooth muscle
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Function
 Regulating blood flow from arteries to capillaries by
regulating resistance according to tissue metabolic needs.
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Contraction of smooth muscle (vasoconstriction)
decrease arteriole diameter
increase resistance
decrease blood flow
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Relaxation of smooth muscles (vasodilation)
increase arteriole diameter
decrease resistance
increase blood flow
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Capillaries
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Microscopic vessels that connects arterioles to venules
Structure
 Single wall layered vesseles (endothelial cells)
 Undergoes extensive branching
Function:
 Exchange of nutrients and wastes between blood and
tissue cells
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Veins
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Carry blood from tissues to heart
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Structure:
 Thin wall
 Less smooth muscle and considerable
amount of collagen
 Less elastic fibers
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Function:
 Passage ways back to heart
 Blood reservoir (capacitance vessels)
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