BIOL BC 1500x Lecture Notes - Lecture 4: Capillary, Hemolymph, Respiratory System
19 Sep 2016
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Document Summary
As animals evolved, they got larger and had more complex bodies, respiratory and circulatory systems developed to accommodate for body sizes. Vascular uids: blood in vertebrates, hemolymph in invertebrates. Compartments: either brings in vascular uid or pushes it out. Branch repeatedly throughout body (bigger animal = more branching) Layers of an artery: endothelium (lines a tube, thin- one or two cell layers), smooth muscle (can contract to change diameter), connective tissue (tough and brous to hold it all together, helps resist pressure by vascular uid) Arteriole: branch of an artery, provides to more speci c tissues. One cell thick, leaky cells so materials can move through/between them. Can be shut down while blood is directed elsewhere (regulated by sphincters) Materials move capillaries-> interstitial uid -> cells (waste moves in reverse) Hydrostatic pressure: pressure from heart, pushes materials out of capillaries, drops from one end of capillary bed to other.
