Crossword clues for depolarization
depolarization
The Collaborative International Dictionary
Depolarization \De*po`lar*i*za"tion\, n. [Cf. F. d['e]polarisation.] The act of depriving of polarity, or the result of such action; reduction to an unpolarized condition.
Depolarization of light (Opt.), a change in the plane of polarization of rays, especially by a crystalline medium, such that the light which had been extinguished by the analyzer reappears as if the polarization had been anulled. The word is inappropriate, as the ray does not return to the unpolarized condition.
Douglas Harper's Etymology Dictionary
1815; see de- + polarization. Related: Depolarize; depolarized.
Wiktionary
alt. The act of depriving of polarity, or the result of such action; reduction to an unpolarized condition. n. The act of depriving of polarity, or the result of such action; reduction to an unpolarized condition.
WordNet
n. a loss of polarity or polarization [syn: depolarisation]
Wikipedia
In biology, depolarization is a sudden change within a cell, during which the cell undergoes a dramatic electrical change. Most cells, especially those that compose the tissues of highly organized animals, typically maintain an internal environment that is negatively charged compared to the cell's surrounding environment. This difference in charge is called the cell's membrane potential. In the process of depolarization, the negative internal charge of the cell becomes positive for a very brief time. This shift from a negative to a positive internal cellular environment allows for the transmission of electrical impulses both within a cell and, in certain instances, between cells. This communicative function of depolarization is essential to the function of many cells, communication between cells, and the overall function of an organism.
Depolarization or depolarizer may refer to:
- Depolarization, a decrease in the absolute value of a cell's membrane potential
- Depolarizer, a substance used to depolarize an electrochemical cell
- Depolarization ratio, the intensity ratio between the parallel component and the perpendicular component of Raman scattered light
- Depolarizer (optics), a device for randomizing the polarization of light
Usage examples of "depolarization".
Both formation and breakup of acetylcholine is brought about with exceeding rapidity, and the chemical changes keep up quite handily with the measured rates of depolarization and repolarization taking place along the course of a nerve fiber.
The secretion of acetylcholine alters the properties of the muscle cell membrane, brings about the influx of sodium ion, and, in short, initiates a wave of depolarization just like that which takes place in a nerve cell.
When depolarization takes place at one point in a membrane, it acts as a stimulation for depolarization elsewhere.
The result is that the depolarization overshoots the mark, and for a moment the interior of the cell takes on a small positive charge, thanks to the surplus of positively charged sodium ions that have entered, and a small negative charge is left outside the cell.
Those adjacent areas depolarize and then polarize slightly in the opposite direction, so as to stimulate depolarization in areas beyond.
In this way a wave of depolarization travels along the entire membrane.
Between the moment of depolarization and the moment of complete repolarization the membrane will not respond to the usual stimuli.
Exactly how the tiny electrical changes involved in a depolarization bring about a particular response is not known, but the fact of response is clear, and so is the fact that the response is unified.
The wave of depolarization travels through a muscle fiber at a rate of anywhere from 0.
On stimulus the resultant depolarization is not translated into muscular contraction or any of the other common responses but makes itself evident, instead, as a flow of electricity.
The wave of depolarization traveling along these nerve-cell processes is referred to as the nerve impulse.
It is this acetylcholine which alters the working of the sodium pump so that depolarization takes place and the nerve impulse is initiated.
According to one view, a hole is poked in the receptor membrane, launching depolarization, but other workers believe that the substance may become bound to the cells possessing specific receptors for it and then may just sit there, somehow displaying its signal from a distance, after the fashion of antigens on immune cells.
Since this happens at every point where the membrane is depolarized, there is a wave of repolarization following behind the wave of depolarization.
There are, nevertheless, three types of stimuli that will bring about depolarization without injuring the cell (if the stimuli are sufficiently gentle).