BIOLOGY 172 Lecture Notes - Lecture 35: Tetrodotoxin, Hypoesthesia, Tetraodontidae
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Membrane potential: charged differential across plasma membrane, set up with b. i. Dirven by na+/k+ atpase, creating a steep na+/k+ gradient b. ii. 1. Hydrolyzes and atp to perform active transport b. ii. 2. Lots of sodium outside, not so much inside; opposite potassium b. ii. 2. a. Potassium is pumped into cells via atpase, but leaks out in leak channels b. iii. 1. Protein anions in the cytoplasm: process c. i. As k moves from interior to exterior via leak channels, the interior of the cell becomes more negatively charged (charge differential) c. ii. Membrane reaches a voltage at which the k moving out = k moving in c. ii. 1. Action potential: change in electric potential that moves down the neuron, ap is triggered by voltage-gated na+ b. i. When they are open, na+ moves freely b. ii. 1. a. Open when membrane is depolarized/ap is triggered b. ii. 2. When they are closed, it does not b. ii. 2. a.
