ANP 1105 Chapter Notes - Chapter 19: Extracellular Fluid, Epithelium, Tunica Intima

• School: University of Ottawa
• Department: Anatomy and Physiology
• Course: ANP 1105
• Professor: Joanne Savory

Document Summary

Anp1105 a dr. joanne savory and dr. m zeroual. Blood vessels: closed delivery system of dynamic structures that begins and ends at the heart. The walls have 3 layers (tunics) surrounding the central blood-containing vessel (lumen): tunica intima: simple squamous epithelium that lines lumen of all vessels. Smooth muscle activity regulated by sympathetic vasomotor nerve fibers of ans (vasoconstriction and vasodilation) Infiltrated with nerve fibers, lymphatic vessels; in larger veins there is a network of elastic fibers. In larger vessels, the tunica externa has vaso vasorum - system of tiny blood vessels found in larger vessels that nourish outermost external layer. Arterioles diameter determine which capillary beds flushed, minute-to-minute blood flow: diameter varies in response to changing neural, hormonal and chemical influences. Resistance arteries b/c changing diameters change resistance to blood flow to the tissues. Capillaries microscopic; smallest blood vessels; walls of thin tunica intima only. Pericytes: smooth muscle-like cells that stabilize capillary walls and control permeability.