HISTOLOGY
BLOOD VESSELS
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
At a capillary bed, a vasoconstrictor
|
|
constrictslocal arterioles, thereby increasing pressure and increasing local bloodflow
|
|
|
stimulates precapillarysphincters and decreases local blood flow
|
|
|
dilateslocal arterioles, thereby increasing pressure and increasing localblood flow
|
|
|
constrictsprecapillary sphincters and thereby increases local blood flow.
|
Explanation:
Detailed explanation-1: -Smooth muscles in the walls of arteries can contract or relax to cause vasoconstriction (narrowing of the lumen of blood vessels) or vasodilation (widening of the lumen of blood vessels).
Detailed explanation-2: -Blood flow through the capillary beds is controlled by precapillary sphincters to increase and decrease flow depending on the body’s needs and is directed by nerve and hormone signals. Lymph vessels take fluid that has leaked out of the blood to the lymph nodes where it is cleaned before returning to the heart.
There is 1 question to complete.