ANP 1105 Chapter Notes - Chapter 9: Tunica Intima, Tunica Externa, Tunica Media

• School: University of Ottawa
• Department: Anatomy and Physiology
• Course: ANP 1105
• Professor: John Copeland

Document Summary

4. 3. 1 structure of blood vessel walls: arteries>>arterioles>>capillaries>>venules>>veins, arteries and veins. Tunica intima, tunica media, and tunica externa: central blood-containing space. Endothelium lines the lumen of all vessels: barrier/exhange function. In vessels larger than 1 mm, a subendothelial connective tissue basement membrane is present. Sympathetic vasomotor nerve fibers control vasoconstriction and vasodilation of vessels: regulates circulatory dynamics. Tunica externa (tunica adventitia: collagen fibers protect and reinforce. Larger vessels contain vasa vasorum to nourish the external layer. Large thick-walled arteries with elastin in all three tunics: aorta and its major branches (2. 5-1cm diameter, a(cid:272)t as (cid:862)pressure reservoirs(cid:863) expand and recoil as blood is ejected from the heart. 4. 3. 2 muscular (distributing) arteries: distal to elastic arteries; deliver blood to body organs, 1cm - 0. 3mm diameter, have thick tunica media with more smooth muscle vs elastin, active in vasoconstriction, less distensible. Tunica media mostly smooth muscle, one layer in smallest arterioles.