PHGY 209 Lecture Notes - Lecture 5: Lamotrigine, Multiple Sclerosis, Alprazolam
17 Mar 2017
School
Department
Course
Professor
Document Summary
Neurons (cells of the ns: ns comprises ~ 100 billion neurons! Gradient: total conc. of positively & negatively charged ions has to be equal on the inside & outside but there is just a tiny bit of excess of negative ions inside. Memb. potential at equil. is described by the nernst equation. If memb. of resting neuron were only permeable to k+, the v diff. would be - ** ap is an all or non event if you hit threshold, you get an ap! This positive feedback mech. results very rapidly in maximal activation of na channels, a large na influx, & depolarization of the memb. from resting level to new level, near ena. Inactivation stops na influx, causing memb. to relax back to original resting level: voltage gated potassium channels, delayed activation of these channels also contributes to falling phase of ap (in addition to.
