BIOL 142 Chapter Notes - Chapter 21-22: Vasoconstriction, Tight Junction, Elastin
9 Jul 2018
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Document Summary
Outermost tunic, composted of areolar or fibrous connective tissue. In larger vessels, the tunica externa contains a system of tiny blood vessels, the vasa vasorum. In general, the walls of arteries are thicker than those of veins. The tunica media in particular tends to be much heavier and contains substantially more smooth muscle and elastic tissues. Act as a pressure reservoir, expanding and recoiling for continuous blood flow. Examples: aorta, brachiocephalic artery, and common carotid artery. Medium-sized arteries, accounting for most arteries found in the body. They have less elastic tissue and more smooth muscle than other arteries. Better ability to constrict and less stretchable than elastic arteries. They distribute blood to specific areas of the body. Smallest arteries with a very thin tunica externa and only a few layers of smooth muscle in the tunica medulla. Blood flows from arterioles into a capillary bed. They play a role in regulating the blood flow to specific areas of the body.
