BIOB32H3 Lecture Notes - Erythropoietin, Ductus Venosus, Aldosterone
28 Mar 2013
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Structure of vessel walls: walls of arteries and veins contain three distinct layers, tunic intima, tunica media, tunica externa. Differences between arteries and veins: compared to veins, arteries, have thicker walls, have more smooth muscle and elastic fibers, are more resilient. Arteries: undergo changes in diameter, vasoconstriction decreases the size of the lumen, vasodilation increases the size of the lumen, classified as either elastic (conducting) or muscular (distribution, small arteries (internal diameter of 30 um or less) are called arterioles. Capillaries: an endothelial tube inside a basal lamina, these vessels, form networks, surround muscle fibers, radiate through connective tissue, weave throughout active tissues, capillaries have two basic structures, continuous, fenestrated, flattened fenestrated capillaries = sinusoids. Capillary beds: an interconnected network of vessels consisting of, collateral arteries feeding an arteriole, metarterioles, arteriovenous anastomoses, capillaries, venules. Veins: collect blood from all tissues and organs and return it to the heart, are classified according to size, venules, medium-sized veins, large veins.
