Step I Hyperkalemia and Accomodation

[pathtopenn]

Hi!

I just need some clarification on the concept of acommodation. In Costanzo: acommodation is described as membrane pot being held in a depolarized level such that threshold pot is passed w/o firing an AP.

In the case of hyperkalemia: The p[K] is elevated, so that means the gradient of K is increase which means that amount of Na needed to activate threshold is increased. Also it states that Na channel is inax by the depolarization which confuses me b/c I would think inax mode is turned on by repolarization.

Can someone please clarify for me?

Thanks!

 

[DarkHorizon]

Hi!

I just need some clarification on the concept of acommodation. In Costanzo: acommodation is described as membrane pot being held in a depolarized level such that threshold pot is passed w/o firing an AP.

In the case of hyperkalemia: The p[K] is elevated, so that means the gradient of K is increase which means that amount of Na needed to activate threshold is increased. Also it states that Na channel is inax by the depolarization which confuses me b/c I would think inax mode is turned on by repolarization.

Can someone please clarify for me?

Thanks!

They are talking about activating and deactivating Na+ channel gates. They have a nice picture in purple costanzo if you are reading that. Depolarization opens both activating and deactivating gates of Na channel. Activating gates are fast and hence there is an influx of Na, deactivating gates are slow to come on and amount to repolarization of a cell.