KINESIOL 1A03 Lecture Notes - Lecture 9: Schwann Cell, Neurotransmission, Action Potential
1 Dec 2014
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Document Summary
Propagation of action potentials: an action potential spreads over the surface of axon. As na+ flows into the cell during depolarization, the voltage of adjacent areas is effected and their voltage-gated na+ channels open. Self-propagating along the membrane: the traveling action potential = nerve impulse. Absolute refractory period: movement of positive ions is called a local current. Myelinated axon: ap conducted from one node of ranvier to another. Saltatory conduction: local current flows between nodes of ranvier, voltage gated na+ channels are concentrated at the nodes, flow of ap"s is much faster because of the leaping effect. Nerve fiber types: type a: large-diameter, myelinated. Motor neurons supplying skeletal and most sensory neurons: type b: medium-diameter, lightly myelinated. Part of ans: type c: small-diameter, unmyelinated. Synapse: how do ap"s on one neuron communicate with other neurons, synapse - the junction between cells that allows one to communicate with another, presynpatic cell, postsynaptic cell, two types of synapses, electrical, chemical.
