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A Handbook of Biology

SÝSTËMÏÇ ÇÏRÇÜLÅTÏØÑ

3

Systemic circulation provides nutrients, O2 and other substances

to the tissues and takes CO2 and other harmful substances

away for elimination.

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Oxygenated blood from left ventricle ® to aorta ® arteries ®

arterioles ® capillaries ® tissues ® deoxygenated blood from

tissues ® venules ® veins ® vena cava ® to right atrium.

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Circulation between heart and various body parts.

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Hepatic portal system : It is a system which includes the hepatic portal

vein that carries blood from intestine to the liver before it is delivered to

the systemic circulation.

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Coronary circulatory system : It is a system of coronary vessels that

circulate blood to and from cardiac musculature.

RËGÜLÅTÏØÑ ØF ÇÅRDÏÅÇ ÅÇTÏVÏTÝ

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Normal activities of heart are auto-regulated by nodal tissues. So, it is

called myogenic heart.

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Medulla Oblongata regulates cardiac activity through ANS.

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Sympathetic nerves of ANS increase the rate of heartbeat, the strength

of ventricular contraction and cardiac output.

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Parasympathetic nerves of ANS decrease the heartbeat, conduction of

action potential and the cardiac output.

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Adrenal medullary hormones increase the cardiac output.

LÝMPHÅTÏÇ SÝSTËM

Includes lymph,

lymph vessels and

lymph nodes

(glands).

As the blood passes

through the capillaries in

tissues, some water and

soluble substances are

filtered out from plasma

to the intercellular

spaces, to form tissue

fluid. It has same mineral

distribution as that in

plasma.

Exchange of

nutrients, gases,

etc. between the

blood and the cells

occur through

tissue fluid

(interstitial fluid).