PSYCH 3313 Lecture Notes - Lecture 6: Axon Hillock, Sodium Channel, Fluid Compartments

• School: Ohio State University
• Department: Psychology
• Course: PSYCH 3313
• Professor: Kristin Supe

Document Summary

Inward flow of chloride, outward flow of potassium. Yes vote for ap: decreases with time and distance. Decrease in strength as they spread out from point of origin: spatial summation. Combines all epsps and ipsps occurring near in time at different locations on the dendrite and cell body. Epsp/ipsp integration: analogue signal is summed over time and space. Action potential = binary signal: temporal summation. Combines all epsps and ipsps occurring near in place at different times on the dendrite and cell body. Role of axon hillock: junction of cell body and axon, contains many voltage-gated channels. If threshold is reached, action potentials are initiated: threshold of excitation. Threshold = membrane potential necessary to trigger an action potential. Causes opening of voltage-gated na+ and (later) voltage-gated k+ Inactivating gate closes at peak of ap: voltage-gated potassium channels. Initiated at axon hillock at threshold of excitation: large, brief reversal in polarity of an axon.