Info

FIGURE 9 Relationship between depolarization and Na+ permeability critical for the initiation of an action potential. (A) Na+ permeability increases as the membrane potential becomes more depolarized. (B) The increase in Na+ permeability produced by some initial depolarization can lead to greater depolarization.

FIGURE 9 Relationship between depolarization and Na+ permeability critical for the initiation of an action potential. (A) Na+ permeability increases as the membrane potential becomes more depolarized. (B) The increase in Na+ permeability produced by some initial depolarization can lead to greater depolarization.

Assume that the cell is depolarized by some stimulus. As a result of the depolarization, there will be an increase in Na+ permeability. If Na+ permeability is increased (assume for the moment that K+ permeability remains unchanged), a in the Goldman-Hodgkin-Katz equation will be increased. If a is increased, the Na+ terms are multiplied by a larger value, and they will tend to dominate the Goldman-Hodgkin-Katz equation. The membrane will become less negative (i.e., more depolarized), but, as the cell depolarizes, Na+ permeability increases further and a increases further. A positive feedback cycle is entered (Fig. 9B) such that once the cell is depolarized to a critical level, the cell will rapidly depolarize further in a regenerative fashion. Eventually, the membrane potential will approach the Na+ equilibrium potential. Thus, a voltage-dependent relationship between membrane potential and Na+ permeability can in principle completely account for the initiation of the action potential.

Get Rid of Gallstones Naturally

Get Rid of Gallstones Naturally

One of the main home remedies that you need to follow to prevent gallstones is a healthy lifestyle. You need to maintain a healthy body weight to prevent gallstones. The following are the best home remedies that will help you to treat and prevent gallstones.

Get My Free Ebook


Post a comment