Unformatted text preview: resistance allows the forward current to flow farther down the axon. 2) In an unmyelinated axon, if they have a higher density of Nav. 3) If they are myelinated, because the lower capacitance and higher resistance of the internodal regions forces current to flow farther down the axon and out at the nodes, which have higher C and lower R. The high density of Nav at the nodes makes this more efficient by amplifying inward current. 4) In a myelinated axon, if the myelin sheath is thicker. In any axon, the speed with which current spreads down the length is the same (and fast!), and the time delay to open Navs is the same (a comparatively slow event of about 0.5 ms). However, if more current spreads farther down the axon before it flows out to trigger opening of Nav, then the Ap will conduct down the axon faster. This is what happens in a myelinated axon....
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This note was uploaded on 05/03/2010 for the course BISC 307L taught by Professor Herrera during the Spring '08 term at USC.
- Spring '08