Role in Action Potential
- See main article: Action potential
Voltage-gated sodium channels play an important role in action potentials. If enough channels open when there is a change in the cell's membrane potential, a small but significant number of Na+ ions will move into the cell down their electrochemical gradient, further depolarizing the cell. Thus, the more Na+ channels localized in a region of a cell's membrane, the faster the action potential will propagate, and the more excitable that area of the cell will be. This is an example of a positive feedback loop. The ability of these channels to assume a closed-inactivated state causes the refractory period and is critical for the propagation of action potentials down an axon.
Na+ channels both open and close more quickly than K+ channels, producing an influx of positive charge (Na+) toward the beginning of the action potential and an efflux (K+) toward the end.
Ligand-gated sodium channels, on the other hand, create the change in the membrane potential in the first place, in response to the binding of a ligand to it.
Read more about this topic: Sodium Channel
Famous quotes containing the words role in, role, action and/or potential:
“Language makes it possible for a child to incorporate his parents verbal prohibitions, to make them part of himself....We dont speak of a conscience yet in the child who is just acquiring language, but we can see very clearly how language plays an indispensable role in the formation of conscience. In fact, the moral achievement of man, the whole complex of factors that go into the organization of conscience is very largely based upon language.”
—Selma H. Fraiberg (20th century)
“Scholars who become politicians are usually assigned the comic role of having to be the good conscience of state policy.”
—Friedrich Nietzsche (18441900)
“When the course of events shall have removed you to distant scenes of action where laurels not nurtured with the blood of my country may be gathered, I shall urge sincere prayers for your obtaining every honor and preferment which may gladden the heart of a soldier.”
—Thomas Jefferson (17431826)
“Children are potentially free and their life directly embodies nothing save potential freedom. Consequently they are not things and cannot be the property either of their parents or others.”
—Georg Wilhelm Friedrich Hegel (17701831)