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:
“So successful has been the camera’s role in beautifying the world that photographs, rather than the world, have become the standard of the beautiful.”
—Susan Sontag (b. 1933)
“His role was as the gentle teacher, the logical, compassionate, caring and articulate teacher, who inspired you so that you wanted to please him more than life itself.”
—Carol Lawrence, U.S. singer, star of West Side Story. Conversations About Bernstein, p. 172, ed. William Westbrook Burton, Oxford University Press (1995)
“These people who are always briskly doing something and as busy as waltzing mice, they have little, sharp, staccato ideas.... But they have no slow, big ideas. And the fewer consoling, noble, shining, free, jovial, magnanimous ideas that come, the more nervously and desperately they rush and run from office to office and up and downstairs, thinking by action at last to make life have some warmth and meaning.”
—Brenda Ueland (1891–1985)
“Most days I feel like an acrobat high above a crowd out of which my own parents, my in-laws, potential employers, phantoms of “other women who do it” and a thousand faceless eyes stare up.”
—Anonymous Mother. Ourselves and Our Children, by Boston Women’s Health Book Collective, ch. 2 (1978)