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:
“My role in society, or any artist or poet’s role, is to try and express what we all feel. Not to tell people how to feel. Not as a preacher, not as a leader, but as a reflection of us all.”
—John Lennon (1940–1980)
“To win by strategy is no less the role of a general than to win by arms.”
—Julius Caesar [Gaius Julius Caesar] (100–44 B.C.)
“For the child whose impulsiveness is indulged, who retains his primitive-discharge mechanisms, is not only an ill-behaved child but a child whose intellectual development is slowed down. No matter how well he is endowed intellectually, if direct action and immediate gratification are the guiding principles of his behavior, there will be less incentive to develop the higher mental processes, to reason, to employ the imagination creatively. . . .”
—Selma H. Fraiberg (20th century)
“Silence is as full of potential wisdom and wit as the unhewn marble of great sculpture. The silent bear no witness against themselves.”
—Aldous Huxley (1894–1963)