PH 122 Lecture Notes - Time Constant, Myelin, Relative Permittivity
Document Summary
A typical cell membrane has a thickness of 7. 0 nm. A wave of potential travels down the axon. Sodium channels open potassium channels open membrane recovery. What is the resistance along the length of a typical axon of length 1. 0 mm and radius 5. 0. Ignore the resistance of the membrane, and assume that the resistivity of the fluid inside the axon is 2. 0 m. The dielectric constant of the cell membrane is 9. 0, and the thickness is a typical 7. 0 nm. Giant axon in the squid: up to 1 mm in diameter. The squid uses the giant axon for escape, rapidly contracting the mantle for a jet propulsion getaway. The giant axon is so large in diameter that it makes for easy study, and squid are cheap specimens. Nerve fibers can be modeled as rc circuits. The fluid in the axon has a certain resistivity. The axon is thin, so the resistance is large.