Depolarization

[lisaR1986]

Hello,

 

I am learning about depolarization in A&P, and there is a part about it that has me stumped. My teacher writes:

 

"At the point of stimulation, mechanical gated or chemical (ligand) gated ion channels open to threshold voltage, then voltage gated Na+ channels open and Na+ rush in..."

 

I am confused. Why do mechanical/ligand gates open to voltage?

 

Chemical gates open to chemical stimulus, mechanical to vibration or pressure, and voltage to voltage. Why does this threshold voltage open up these other gates, if they aren't "supposed" to be able to open to anything else?

 

Your clarification would be MUCH appreciated!!!

[Ringer]

The voltage or ligand gated channels open due to their respective stimuli to let in (or out) ions. The ions change the potential to threshold, that's when the voltage gated channels open. So the ligand and mechanical are the cause of the ion concentration change that lead to the voltage gates to open.

 

[edit] To be a bit clearer, the voltage doesn't effect the mechanical or ligand channels, they effect the potential of the cell and lead to the threshold. But any channel can have multiple types of gated types. [/edit]

Edited June 25, 2014 by Ringer