ANP 1105 Lecture Notes - Lecture 16: Tunica Intima, Tunica Externa, Vasomotor Center

• School: University of Ottawa
• Department: Anatomy and Physiology
• Course: ANP 1105
• Professor: Jackie Carnegie

Document Summary

Bulkiest layer, responsible for blood pressure and circulation: tunica externa: loose collagen fibers, protect and reinforce the vessel and anchors it to surrounding tissue. Contains nerve fibers, lymphatic vessels and vasa vasorum (smaller blood vessels to supply bigger blood vessel tissue) Elastic arteries: think walls, every tunic has elastin, biggest arteries, aorta and conduction pathways, not much vasoconstriction but more of elasticity, can weaken over time. Muscular arteries: delivers blood to organs, contains the thickest tunica media of all arteries, more muscular tissue and less elastin (less stretching and more vasoconstriction). Does contain an elastin membrane on face of tunica media. Arterioles: can have all three tunics but the smaller arterioles have muscle tissue and an endothelial layer, during constriction, a lot of resistance against. Rbcs: chemical influences and hormones determine vessel diameter. Venules: postcapillary vneules: smallest venules, entirely made of endothelium pericytes, extremely porous, larger venules have one or two layers of smooth muscle and a thin tunica externa.