PHYSIOLOGY
CARDIOVASCULAR PHYSIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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because they do not need to pump blood
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because they are found only in the smallest organs and tissues
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because they maximize diffusion of nutrients
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because blood only travels through them slowly
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Detailed explanation-1: -To maximise the area available for diffusion, there are many capillaries supplying the same tissue. Moreover, a constant blood flow through the capillaries maintains a large concentration gradient to allow the molecules to be rapidly exchanged with the tissue.
Detailed explanation-2: -Roles of Capillaries In addition to forming the connection between the arteries and veins, capillaries have a vital role in the exchange of gases, nutrients, and metabolic waste products between the blood and the tissue cells. Substances pass through the capillary wall by diffusion, filtration, and osmosis.
Detailed explanation-3: -Capillaries are thin-walled vessels composed of a single endothelial layer. Because of the thin walls of the capillary, the exchange of nutrients and metabolites occurs primarily via diffusion.