Physiology 3120 Lecture Notes - Lecture 20: Sodium-Potassium Alloy, Hyperaemia, Tunica Externa
Document Summary
Arterial vessels able to contract due to presence of more smooth muscles. Tunica intima made up of single layer of endothelial cells that sense substances in blood and tell smooth muscle cells to contract if need be act like sensors. Tunica media made up of many layers of smooth muscle (fewer layers in veins) Tunica adventitia made up of ct that act as barrier type depends on vessel. Eg: aorta needs protection via barrier to prevent bursting thus needs to be strong ct = uses collagen. Eg: needs to be stretchy ct = uses elastin. Know the differences between (numbers just for scale) Most smooth muscle in artery, then arterioles (since resistance vessels) Capillary does not have any elastic, muscle or fibrous ct has only one layer of endothelial cells (exam ques: which of the following does not have 3 layers?) Capillary only has one cell layer for easy exchange (diffusion) Fibrous ct means collagen thus elastic vs. collagen differences.