ANA300Y1 Lecture Notes - Lecture 7: Tunica Intima, Tunica Externa, Vascular Smooth Muscle
Document Summary
Cvs is a closed system: blood doesn"t leave closed loop, heart is a double pump: pushes blood through 2 systems of tubes. Right side moves blood through pulmonary circulation. Left side moves blood through systemic circulation: arteries: carry blood away from the heart. Right side has pulmonary arteries deoxygentated blood: veins carry blood towards the heart: Systemic veins carry deoxygenated blood: gas exchange occurs at the capillaries. Structure of large bvs: walls of arteries and veins have 3 layers: 1) (layer closest to contained blood) = tunica intima consists of endothelium and sub endothelial fibroelastic. Some vessels have an elastic layer: subendothelial fibroelastic ct. 2) tunica intermedia: layers of smooth muscle that spiral around vessel: increases vascular resistance with contraction of smooth muscle. In some arteries there is a fenestrated elastic layer: not a barrier to molecular movement. In some arteries, there"s an external elastic lamina. Ct sheath connects bv to connective tissue of surrounding muscle.
