BIOL 2410 Lecture Notes - Lecture 4: Upper Set, Myelin, Axon Hillock

• School: University of Manitoba
• Department: Biological Sciences
• Course: BIOL 2410
• Professor: Kevin Scott

Document Summary

Occur in dendrites and cell body: can occur near axon terminals as well but this is rare. See figure 8. 7: local current flow, wave of depolarization around the point of initiation, convention: current in biology is the net movement of positive electrical charge. Combination of these two factors lead to the decrease in amplitude as the current flows down the distance of the neuron. Depolarizing graded potentials: considered excitatory, they trigger action potentials. Hyperpolarizing graded potentials: considered inhibitory, move the neuron further away from threshold, and action potential firing. Subthreshold: graded potential is not strong enough to depolarize the membrane at the trigger zone and therefore no action potential is fired and the signal dies out. Suprathreshold: graded potential is strong enough to fire an action potential, current is above threshold at the trigger zone, excitability: the ability of a neuron to respond to a stimulus and fire an action potential.