BIO304H5 Lecture 3: BIO304 Lecture 3 Cont.
Document Summary
In 1902, julius bernstein hypothesized that rmp depends only on k+ out vs k+in. So the k+ gradient sets the rmp meaning the na+ ions and other ions don"t matter. In reality, if the k+ gradient is maintained by pumps/exchanges, it will continue to. And if the na+ gradient is maintained by pumps/exchanges it will continue flow rmp = e k to flow under rmp = e na. Young developed the famous squid giant axon preparation. A giant axon that innervates muscles in the squid mantle. Then neurobiologists started using the squid axon for electrophysiological experiments - the axon was so large, one could easily insert a recording electrode along its length. Intracellular recording permits measurement of voltage across the axon"s cell membrane. Hodgkins and keynes used this prep to test bernstein"s hypothesis. If bernstein was right, according to nernst, changing (k) while keeping (k) constant, should change e, and rmp/membrane voltage (vm) should follow ex.
