BIOL 1221 Lecture Notes - Lecture 7: Vascular Permeability, Tunica Media, Tight Junction
22 Jun 2017
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Document Summary
The structure and general function of the major types of blood vessels. Arteries: carry blood away from the heart (branches) Elastic arteries: thick walled arteries near the heart. Conduct blood from the heart to medium sized arteries. Contain more elastin, and present in all tunics. Elastic arteries are pressure reservoirs, which expand and recoil when the heart is ejecting blood. Blood flows smoothly continuously instead of starting and stopping. Have the thickest tunica media, which contains more smooth muscle. More active in vasoconstriction and less capable of stretching. In muscular arteries there an elastic membrane on each face of the tunica membrane. Blood flow is determined by the arteriolar diameter, and changes depending on the neural, hormonal and local chemical influences. During constriction the tissues served are largely bypassed. During dilation blood flow into capillaries increases. Have direct contact with tissue cells and serve cellular needs. Only one red blood cell can move through the capillary at a time.
