Physiology 2130 Lecture 4: module 4 notes - nerves
10 Oct 2020
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What are the advantages of saltatory conduction: describe what is meant by the all-or-nothing principle of action potential conduction, explain what determines the direction of the conduction of the action potential. Structure of a nerve: this particular neuron below is called a multipolar neuron. Cell body (soma: thin, branch-like, receives incoming signals, control centre of nerve cell. Inactivation gate closes and na+, can no longer flow into the cell; the channel cannot open: channel returns to resting configuration (inactivation gate open and activation gate closed, channel is now ready to open again. Voltage-gated potassium channels: the voltage-gated k+ channels contain only 1 gate, which opens when the membrane depolarizes, however, they do not open immediately like the na+ voltage-gated channels. In fact, they begin opening when the na+ voltage-gated channels start to become inactivated: extremely important difference between the 2 channels. The action potential: during an action potential, the membrane potential rapidly reverses from -70 mv to roughly +35 mv.
