Physiology 2130 Lecture Notes - Lecture 5: Axon Hillock, Potassium Channel, Myelin

• School: Western University
• Department: Physiology
• Course: Physiology 2130
• Professor: Anita Woods

Document Summary

Role of sodium/potassium + atpase in rmp: moves sodium out of the cell, moves potassium into the cell, overall: maintains concentration gradients. Excitable cells: excitable cells: generate and respond to electrical signals. Includes neurons and muscle cells (cardiac, smooth, skeletal: neurons use electrical signals (in the form of action potentials) to receive, process, initiate, and transmit messages. Ion movement creates electrical signals: also, at rest, the cell is only slightly permeable to sodium, therefore, if we change the permeability of the cell to sodium we can change its electrical potential. Action potential: at the axon hillock, if the threshold is reached (-55mv), then an action potential will be propagated down the axon, 3 important things about action potentials. Undirectional: action potential always flows from the axon hillock to the axon terminals. All or nothing: if a graded potential of -55mv is reached, an action potential will fire. Will open at a voltage of: -55mv.