Lecture 37 notes W11

Lecture 37 notes W11 - Lecture 37 (4-15-11) Notes I. Nerve...

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Lecture 37 (4-15-11) Notes I. Nerve cells A. Three different portions of a nerve cell 1. Dendrites – receive electrical signals from other nerve cells. 2. Cell body – contains the nucleus and other organelles and generates a nerve impulse. 3. Axon – long process that transmits the impulse to another cell. II. Membrane potential A. A change in voltage across a membrane caused by an unequal distribution of positive and negatively charged ions. B. At rest, most animals cells (including nerves) have a negative membrane potential (e.g., -40 to –70mV) C. Two proteins have the biggest influence on the membrane potential. 1. Na + /K + -ATPase – Contributes to a negative membrane potential by pumping in three K+ ions for every two Na+ that are pumped out per ATP hydrolysed. 2. K + leak channels – Always open, letting K+ ions out of the cell. 3. The K + leak channels are responsible for 90% of the negative membrane potential, though ultimately the Na + /K + -ATPase is required for the leak channel to let K + out. D. The Na/K ATPase creates an intracellular environment where there is low Na + inside the cell and high outside; opposite for K + 1. Typical inside cellular environment – 10 mM Na + ; 140 mM K
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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 37 notes W11 - Lecture 37 (4-15-11) Notes I. Nerve...

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