Phases of The Cardiac Action Potential
The standard model used to understand the cardiac action potential is the action potential of the ventricular myocyte. The action potential has 5 phases (numbered 0-4). Phase 4 is the resting membrane potential, and describes the membrane potential when the cell is not being stimulated.
Once the cell is electrically stimulated (typically by an electric current from an adjacent cell), it begins a sequence of actions involving the influx and efflux of multiple cations and anions that together produce the action potential of the cell, propagating the electrical stimulation to the cells that lie adjacent to it. In this fashion, an electrical stimulation is conducted from one cell to all the cells that are adjacent to it, to all the cells of the heart.
Read more about this topic: Cardiac Action Potential
Famous quotes containing the words phases of, phases, action and/or potential:
“That man is to be pitied who cannot enjoy social intercourse without eating and drinking. The lowest orders, it is true, cannot imagine a cheerful assembly without the attractions of the table, and this reflection alone should induce all who aim at intellectual culture to endeavor to avoid placing the choicest phases of social life on such a basis.”
—Mrs. H. O. Ward (1824–1899)
“This socialism will develop in all its phases until it reaches its own extremes and absurdities. Then once again a cry of denial will break from the titanic chest of the revolutionary minority and again a mortal struggle will begin, in which socialism will play the role of contemporary conservatism and will be overwhelmed in the subsequent revolution, as yet unknown to us.”
—Alexander Herzen (1812–1870)
“Economic depression can not be cured by legislative action or executive pronouncement.”
—Herbert Hoover (1874–1964)
“The traditional American husband and father had the responsibilities—and the privileges—of playing the role of primary provider. Sharing that role is not easy. To yield exclusive access to the role is to surrender some of the potential for fulfilling the hero fantasy—a fantasy that appeals to us all. The loss is far from trivial.”
—Faye J. Crosby (20th century)