HUBS1404 Lecture Notes - Lecture 4: Blood Vessel, Capillary, Hematocrit
19 Jul 2018
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Document Summary
Circulation is comprised of different sized blood vessels. Arteriole side: tunica media - ring of smooth muscle cells, tunica externa - rings of connective tissue separating blood vessels from surrounding tissues (adventitia layer) Venous side: a lot less smooth muscle. Blood vessel structure blood vessels differ from simple tubes: elastic walls. Endothelial cells that line the inside of the blood vessels have an important physiological role. Release paracrine hormones onto the smooth muscles and can modulate the muscle. Vessel walls: arteries and veins differ in wall thickness (at similar levels of circulation, arteries tend to also be rounder. Systemic arteries deal with high pressures, veins deal with low pressure. Compliance - a measure of dispensability - how much give they have. Compliance = volume/ pressure: arteries need to withstand high pressures. They are not very compliant and act as resistors: pressure in veins is very low. They have a high compliance and act as capacitors (they store stuff)
