using your knowledge 29

in coronary bypass surgery, a section of the vein is used to replace occluded coronary arteries. Over time, the vein wall becomes more like an arterial wall. Describe the change that would occur in the vein wall.
the tunica media would become thicker, containing more smooth muscle and elastic fibers

the smooth muscle fibers within the wall of an artery do not receive their nutrients from the blood within the lumen of the artery. why not?
arterial wall is too thick for nutrients from blood to diffuse to the smooth muscle fibers

blood flow within the capillaries is slower than within arterial or venous vessels. explain why this is important
blood flow must be slow to allow time for nutrients and wastes to diffuse across the capillary wall

blood flow to the skeletal muscles increases with exercise. explain how the autonomic nervous system mediates the increase in blood flow to skeletal muscles
the autonomic nervous system dilates arterial vessels within skeletal muscles to increase blood flow

explain how blood flow to the kidneys is decreased with exercise?
kidneys obtain 25% of the cardiac output at rest. To provide an increased blood flow to skeletal muscles to supply them with nutrients during exercise, the body decreases blood flow to other areas, including the kidneys

explain why the differences in the amount of elastic fibers and smooth muscle fibers in the tunica media of elastic arteries and muscular arteries is important to their function
experience greater pressure fluctuations than muscular arteries. They allow stretching and recoiling. Smooth muscle fiber abundance can be constricted or dilated to control blood flow

why does the tunica interna of the vasoconstricted section of the arteriole exhibit folds?
it is constricted. The tunica interna folds during constriction

capillaries within the brain have tight junctions, whereas capillaries within the anterior pituitary and other endocrine glands contain fenestrations, intercellular clefts, and vesicles for transcytosis. Explain how these structural differences are important to the function of the brain and the anterior pituitary
exhibit more tight junctions, contributing to the blood-brain barrier. That controls what substances enter the nervous tissue. Blood vessels of anterior pituitary have fenestrations, intercellular clefts, and vesicles for transcytosis to allow hormones traveling from other areas of the body to enter anterior pituitary and effect changes in secretion and allow hormones secreted by anterior pituitary cells to enter blood vessels and to be carried to target cells in the body

compare the strength of arterial and capillary walls
arterial walls contain smooth muscle and more elastic and collagen fibers and are much stronger than capillary walls. The arterial walls must carry blood and higher pressure than capillaries

Marfan syndrome is an inherited genetic disorder that results in malformed elastic fibers that are weak. What effect would this have on the aorta?
the aorta wouldn’t be able to recoil to move blood efficiently. Areas that don’t recoil may weaken from aneurysms

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