Action Potential

Action Potential - 1. Action Potential Resting Membrane...

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1. Action Potential Resting Membrane Potential - consequence of electrostatic and chemical gradients (- 60mV inside cell) +/- ions "leaky membrane " in neurons --> sodium and potassium would flow across membrane until 0mV reached, but sodium/ potassium pump maintains potential -60mV = polarized membrane Hyper polarized = > -60mV (more negative) Depolarized = < -60mV (closer to zero) Action potential is a binary signal (on/off) 2 Different types of channels in membrane 1. Voltage-gated Open/close in response to voltage --> Sodium channel Voltage sensitive Timer of 1ms Absolute Refractory period (no matter what voltage does, channel will not re- open during this period) Animal toxins are known to block Na channels and prevent the cell from producing Aps Ex) Scorpions, ovaries of puffer fish --> Potassium channel Slow Slow to respond to voltage and slow to close again Sodium Potassium Chloride Calcium Proteins Outside Cell Many Few Many Many Few Inside Cell Few Many Few Few Many
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Calcium: important in generating neurotransmitter release in pre-synaptic membrane 2. Ligand-gated Any ligand can bind
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This note was uploaded on 04/05/2008 for the course BIOL 455 taught by Professor Sabrinaburmeister during the Spring '08 term at UNC.

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Action Potential - 1. Action Potential Resting Membrane...

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