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Cardiovascular System
by
M. Rasjad Indra
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Main function
Serve a transportation for:
Supplying nutrition and oxygen to tissues
Elimination of metabolic end products from
tissues
Hormones & other chemical substances as a
intercellular communication mediator
Maintain a stable internal environment fora life & optimal function of cells.
How does this system regulate its activities to achieve the
function???
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Blood flow
Blood pressure
Tissue perfussion (Supply
nutrition & oxygen and eliminate
metabolic waste products)
Cardic pumping
Local blood vesselresisstance
Total blood vessel
resisstance
Cardiac muscle
contraction
Action potential
Cardiac muscle &
cunductive system
Heart Space &
Valves
Vasoconstriction /
dilatation
Vascular smooth
muscle
Cardiac
cycle
Blood volume
Theoritical Framework of Cardiavascular System
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For better understanding the mechanism of regulation you
have to recognize many parameters of the system:
1. Cardiac output [CO]
2. Blood pressure [P]3. Blood flow [Q]
4. Vascular resistant [R]
Cardiac output= Stroke Volume x Frequency
R
PQ
Ohm law:l
Q
8
Pr4
Poiseuille law:
r = radius
d= blood viscosity
l= blood vessel length
Stroke volume = End Diastolic Vol. - End Systolic Vol.
Cardiac index = Cardiac output / Body Surface Area
Ejection Fraction=(SV/EDV) x 100 %
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Role of each CVS compartmentHeart: Blood pumping
Arteri: Blood transport under high pressure to tissues.
Ateriole: Regulate blood flow to capillaries
Capillary: Fluid exchange, nutrition, electrolites hormone
between plasma & interstitial
Venula: Blood flow from capillaries to middle veins
Vein: Blood flow from tissues to heart
Regulated blood reservoir.
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Blood Volume in Cardiovascular
System
84 % in systemic circulation:
64 % in vein
13 % in artery
7 % in arteriole and capillaries
16 % pulmonary & cardiac circulation:
7 % in the heart
9 % in the lungs
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Parameter Aorta Small artery Arteriole Capillary V. Cava
Number 1 8000 2 x 107 1 x 1010 1
Radius 1,13,cm 0,5 mm 15 m 3 m 1,38 cm
Diameter 4 cm2 7,9 x 10-3 cm2 7,1 x 10-7 cm2 2,8 x 10-7 cm2 6 cm2
Total diameter 4 cm2 63 cm2 141 cm2 2827 cm2 6 cm2
Total blood flow 83 ml/second 83 ml/second 83 ml/second 83 ml/second 83 ml/scnd
Mean of Linier velocity 21 cm/secnd 1,3 cm/second 0,6 cm/second 0,003 cm/sc 14 cm/scnd
Blood flow per unit 83 ml/second 0,01 ml/secnd 4 x 10-6 ml/scnd 8 x 10-9 ml/sc 83 ml/scnd
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Diameter of Blood Vessels
Blood vessel Diameter (cm2)
Aorta 2,5
Small Arteries 20
Arteriole 40
Capillaries 2500
Venule 250Small Vein 80
Vena cava 8
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Blood Flow
In aorta: 33 cm / second
In capillary: 0,3 mm / second
The blood flow going slower because of
decreasing blood pressure and increasing total
diameter of blood vessels
Capillaries length: 0,3 1 mm blood stay incapillary 1 3 seconds
Very short time for fluid exchange betweenplasma and interstitial !!!!
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Blood pressure
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3 Basic Principles of
Cardiovascular Function
1. Tissue blood flow is regulated in
accordance with tissue metabolic need.
2. Cardiac output is controlled mainly by
total tissue blood flow / metabolic need.
3. Blood pressure is determined by a
balance between regulation of tissue
blood flow and cardiac output regulation
mechanism.
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