Lecture 31 notes W11

Lecture 31 notes W11 - Lecture 31 (4-1-11) Notes I....

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Lecture 31 (4-1-11) Notes I. Epithelial tissues. A. Form a barrier between the outside environment and inside an animal. B. Epithelial layers are comprised of polarized cells that have an apical membrane (contacts the outside) and basolateral membrane (contacts the inside of the organism). 1. These membranes are separated by tight junctions, which also prevent leakage between cells. 2. Apical and basolateral membranes can have different transport proteins, which allow the epithelial to perform specific functions. C. Epithelial tissues have a high surface/volume ratio, to maximize the area for transport of molecules across the membrane. II. Homeostasis – maintaining a constant internal environment in the face of external changes A. Sensor detects a change in internal environment (drop in body temperature). B. Integrator processes this information (central nervous system). C. Effector corrects the alteration (shivering; constriction of vessels in extremities) III. Countercurrent exchanger A. Two adjacent vessels carrying fluids flowing in opposite directions B. In the tongue of gray whale, blood through the arteries carries heat from the body core and countercurrent veins capture a significant portion of the dissipating heat to keep it in the body. IV. Osmosis
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This note was uploaded on 02/13/2012 for the course BIO 172 taught by Professor Clark during the Winter '08 term at University of Michigan.

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Lecture 31 notes W11 - Lecture 31 (4-1-11) Notes I....

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