CAS BI 106 Lecture Notes - Lecture 16: Tunica Intima, Tunica Externa, Simple Squamous Epithelium
Document Summary
Three main types: arteries (away from hear, capillaries, veins (return to heart) Vocab: anastomosis 2 or more arteries converge to feed the same body region, end artery single artery if no anastomoses, companion vessels artery travels alongside the vein that drains the same region. Veins: bigger walls relative to lumen, always branching and getting smaller, higher pressure (closer to heart, most arteries carry oxygenated blood, always lead away from heart, usually deeper. Low pressure: bigger lumens relative to walls, always joining and getting bigger, most veins carry deoxygenated blood, always lead to heart, usually more superficial. Larger veins have valves to protect against backflow. Arteries vs. veins: arteries more collagen and elastic in all tunics (stay open when empty, veins collapse when empty (death) Types of arteries: elastic, largest arteries, lots of eleastic fibers allow artery to stretch when blood is pumped in, muscular, less elastic, more muscle.
