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:
“Certainly parents play a crucial role in the lives of individuals who are intellectually gifted or creatively talented. But this role is not one of active instruction, of teaching children skills,... rather, it is support and encouragement parents give children and the intellectual climate that they create in the home which seem to be the critical factors.”
—David Elkind (20th century)
“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)
“The Oriental philosophy approaches easily loftier themes than the modern aspires to; and no wonder if it sometimes prattle about them. It only assigns their due rank respectively to Action and Contemplation, or rather does full justice to the latter. Western philosophers have not conceived of the significance of Contemplation in their sense.”
—Henry David Thoreau (1817–1862)
“Laughing at someone else is an excellent way of learning how to laugh at oneself; and questioning what seem to be the absurd beliefs of another group is a good way of recognizing the potential absurdity of many of one’s own cherished beliefs.”
—Gore Vidal (b. 1925)