Cardiovascular Essay

380 Words2 Pages
BLOOD VESSELS Five types of blood vessels: arteries, arterioles,capillaries,venuels, veins. Arteries carry blood away from heart. Medium arteries divide in to small and small devided in to smaller arteries called arteriole. Arteriole enter tissue and devide in to numerous tiny branches called capillaries. Group of capillaries reunite to make small vein called venolues. Venules reunite to make larger blood vessles called vein that carry blood to the heart. Angiogenesis refers to growth of bloodvessels. Which help in embryo and fetal development. Wound healing, formation of new uterine line after menstruation. Anangeogenesis inhibit could stop growth of tumor and stop blindness because of diabetic. Arteries: has three tunics. The inner most part is tunica interna, middle part is tunica media and the outer most part is tunica externa. Tunica interna made up of simplesquamas epithelium called endothelium, basement layer, and layer of elastic tissue called internal elastic lamina. Endothelium is the linr inner surface of entire cardiovascular system. Tunica interna is the closest to lumen which is the hollow center through blood flows. Tunica medial has smooth muscles fibers, elastic fibers. Thickest layer. Smooth muscles fibers circulres around lumen like ring in the finger. Easily starch and expand in increasing pressure, because of these fibers. Tunica externa made up of elastic and collagen fibers. Sumpathetic neurons of the autonomic nervous system is attach to smooth muscles of tunica media. In sympathetic stimulation smooth muscles contrast and narrowing lumen and decrease blood flow.called vacocontriction. When sympathetic stimulation decrease and chemicals like h+, oxide, the diameter of lumen increase. Elastic arteries is the largest diameter. Contain high portion of elastic fibers in tunica media. The wall are thin compare to all over diameter.

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