{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

BIO 365R Lecture 4 - Properties of action potentials The...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
Properties of action potentials
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
The action potential Threshold • overshoot • peak of AP • repolarization • after hyperpolarization • refractory period •All-or-none (I) Refractory period 1 msec.
Background image of page 2
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
http://www.blackwellpublishing.com/ matthews/channel.html
Background image of page 4
Great moments in the study of the action potential: the pre-classical age. 1902--Bernstein suggested that RP is due to selective permeability to K + (based on Nernst eq.). He also proposed breakdown of the membrane, predicted V m = 0 mV during the AP.--He could not explain how the membrane repolarizes and how the initial ionic conditions were restored. 1902--Overton, based on work by Sidney Ringer, demonstrated that Na + ions are necessary for electrical excitability. His work was largely ignored until rediscovered by Hodgkin and Huxley in the mid 1940s. 1936--JZ Young discovered the squid giant axon.--The classical age of membrane biophysics begins!!
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
1937--Cole & Curtis record from squid axons, show conductance increase during AP-- support Bernstein’s concept of membrane breakdown. K.S. “Kacey” Cole AP Membrane conductance (1900-1984)
Background image of page 6
1937--Hodgkin visits Cole to learn about squid axon. “some scientists here have been getting most exciting results on the giant nerve fibres of the squid. As you know I spend my time working with single nerve fibres from crabs which are only 1/1000th of an inch thick. Well the squid has one fibre which is about 50 times larger than mine and Dr Cole has been using this and getting results which made everyone else's look silly. Their results are almost too exciting because it is a little disturbing to see the answers to experiments that you have planned to do coming out so beautifully in someone else's hands. …. I don't see any prospect of being able to do this myself.”(Hodgkin 1937).
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}