1. Intro-cvs Kbi

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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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1. Intro-cvs Kbi