PHYSIOLOGY
BLOOD PHYSIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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It would decrease blood flow
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It would increase blood flow
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Blood flow would not be influenced by changes in blood vessel diameter
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None of the above
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Detailed explanation-1: -As the total cross-sectional area of the vessels increases, the velocity of flow decreases. Blood flow is slowest in the capillaries, which allows time for exchange of gases and nutrients.
Detailed explanation-2: -The effect of vessel diameter on resistance is inverse: Given the same volume of blood, an increased diameter means there is less blood contacting the vessel wall, thus lower friction and lower resistance, subsequently increasing flow.
Detailed explanation-3: -Vasodilation is the widening of blood vessels as a result of the relaxation of the blood vessel’s muscular walls. Vasodilation is a mechanism to enhance blood flow to areas of the body that are lacking oxygen and/or nutrients.
Detailed explanation-4: -Dilation of arterioles causes a decrease in resistance, increasing blood flow to downstream capillaries and a smaller decrease in blood pressure.