Welcome to JAAN's science class!!

Big hi to all of you! I'm an undergraduate following a Bsc in bioscience. Trust me I know the feeling of surfing around the net for ages and getting nothing in return! Or getting something worthless for the time we spent surfing. So I started this blog adding the science stuff I have noted which I think might help someone in their home work. Ok then enjoy!

21 March 2012

Sequence of events take place during action potential in brief


>In resting state, membrane is permeable to K+ and relatively impermeable to Na+.

>When a stimulus depolarize the membrane into the threshold value the voltage gated Na+ channels open, vastly increasing the membrane’s permeability to Na+.

>Na+ enters the cell across the membrane under the influence of both concentration gradient and the electric gradient.

>Na+ makes the membrane more depolarized and that makes more voltage gated sodium channels to open.

>As the membrane potential approaches equilibrium potential of Na+ the driving force of Na+ is reduced. Therefore less number of Na+ reach into the cell.

>After a short time the voltage gated Na+ channels are inactivated and stop the taken in of the Na+.  Here the membrane potential rise to +45mV.

>As this occurs, the voltage gated K+ channels open and greatly increases the permeability to K+ ions. Therefore K+ leaves the cell under the influence of concentration gradient and electric gradient.

>As K+ leaves, the positive charge inside the cell is reduced. After awhile the equilibrium potential of K+ is obtained and the membrane is hyperpolarized. Now the membrane potential is -75mV. Hyperpolarization is due to the delay of closing the K+ channels compared to Na+ channels.

>The voltage gated K+ channels close and by then the Na+ channels recovered by inactivation.


2 comments:

  1. This is really interesting. Very useful information has been conveyed in this article! Thanks for sharing.

    ReplyDelete