ANP 1105 Chapter Notes - Chapter 19: Tunica Externa, Tunica Intima, Tunica Media

• School: University of Ottawa
• Department: Anatomy and Physiology
• Course: ANP 1105
• Professor: Frank Feiner

Document Summary

Gossamer-thin walls: all bv (except smallest) have 3 layers/tunics that surround a central blood-containing space. Vessel lumen : innermost tunic = tunica intima contact with blood in lumen. contains endothelium (simple squamous epithelium that lines lumen of all vessels). Endothelium continuous with endocardial lining of heart, at cells t close together forming slick surface so minimize friction as bloodd moves through lumen. Depends on body needs; regulation either causes vasoconstriction (lumen diameter decreases a. Sm contracts) or vasodilation. activity of tunica media critical in regulating circulatory dynamics bc small changes in vessel diameter in uence blood ow/pressure. Bulkiest layer. responsible for maintaining blood pressure & circ: outermost layer = tunica externa composed of loosely woven collagen bers; protect and reinforce vessel and anchor to surrounding structures. in ltrated with nerve bers, lymphatic vessels. There, elastin constructs holey sheets of elastic ct bwtn layers of sm. Pressure reservoirs; expanding/recoiling as heart ejects blood. in arteriosclerosis (bv are hard and unyielding); blood.