PSYCH 7A Lecture Notes - Lecture 6: Resting Potential, Membrane Potential, Axon Terminal
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PSYCH 7A Full Course Notes
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Negatively charged protein ions inside cell never pass through membrane. K+ and cl- can pass freely through membrane, but the neg. charge of protein ions makes k+ more concentrated inside the cell and cl- concentrated outside the cell. Na+ ions are outside of cell bc too big to pass through membrane. However, membrane leaks a bit na+ leaks in and forces out k+ Sodium-potassium pump: active mechanism that pumps out na+ at the same rate that they leak in and pumps in k+ at the same rate they leak out. When stimulation exceeds excitatory threshold, neuron fires. Voltage gated ion channels open allow na+ to rush into axon. Na+ rushes in, pushing voltage to positive. Depolarization causes voltage gated k+ channels to open k+ move quickly out of cell. Then, na+ channels close and axon repolarizes. K+ continue to exit cell, lowering inner voltage. Na+ start moving out of cell again.
