Question

ana ion channels. The two ions in questions are Na+ (sodium ion) and K+ (potassium ion). The on channels/pumps are a) voltage-gated sodium channel, b) voltage-gated potassium channel, and c) sodium/potassium pump. a) Depolarization: b) Repolarization: c) Restoring ion concentrations:

Answer 1

Answer :-

a). Depolarization :- The depolarisation process begins with a stimulus. Simple touch, light, foreign particle or even electrical stimulus can be this stimuli. This stimulation causes the cell to change in voltage. This initial change in stress triggers the opening of sodium and calcium channels within the cell membrane.

b). Repolarization :- Voltage-gated potassium channels have K+-selective pores formed by membranedepolarization. This opening allows K+ ions to travel across the plasma membrane and produce K+ currents that appear to repolarize the membrane towards K+ (EK) equilibrium potential.The transition from depolarization to repolarization depends on the kinetic mechanisms of both K+ and Na+ channels gated by voltage. Although both Na+ and K+ voltage gated channels activate at approximately the same voltage (-50 mV), Na+ channels have faster kinetics and turn on / off much faster.Repolarization occurs as the influx of Na+ decreases (channels disinactivate) and as its channels expand, the efflux of K+ ions increases.

C). Restoring ion concentration:- The voltage-gated potassium channels remain open a little longer than is required to return the membrane to its ability of rest. It results in an effect of "undershooting," in which the membrane potential dips slightly lower (more negative) than its resting potential. The voltage-gated potassium channels eventually close, and the membrane future stabilizes at resting future. The sodium channels return to their normal state (remaining closed but once again becoming voltage responsive). The potential process of operation can then begin again.