BIO304H5 Lecture Notes - Lecture 5: Action Potential, Squid Giant Axon, Membrane Potential
Document Summary
Greater number of k+ leaky channels in membrane: k+ makes a greater contribution. Cl is limited by fewer leaky channels. Squid giant axon is permeable to na+ and k+ only: na greater inside than outside, k+ want to move out of the cell. To calculate membrane potential: if one increases the other decreases, sodium conductance to potassium conductance, gna/gk. Lets us see the changes in membrane potential as we change conductance. As sodium is increased (moving into cell) membrane is more positive: when potassium dominates membrane becomes more negative. Conductance can change if we open or close ion channels: if they"re open, conductance of an ion is high, if they"re closed, conductance of an ion is low, going from negative to positive.
