NEUR 2202 Lecture Notes - Lecture 6: Axon Hillock, Threshold Potential, Resting Potential
6 Mar 2019
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Cation: positively charged; anions: negatively charged starts at the cell body and moves down the axon. Note: for the proteins (a-), they are anchored inside the cell. Concentration gradient movement of jon"s from one area of high con to low intracellular environ vs. extracellular environ when nothing is happening. Note: for every 3 na+ out, 2 k+ get pulled in; it makes the inside of the cell more negative temporal summation: sum up the pulses that are close together in time. Spatial summation: sum up the pulses that are close together with respect to location. Summation occurs at the axon hillock more than 50,000 connections to other neurons. Nerve impulses can be excitatory or inhibitory brief depolarization (more positive) of the neuron. More likely to fire when it is positive. Graded potentials: brief polarization (more negative) of the neuron. Less likely to fire when neuron is possible.
