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Biology-online is a completely free and open Biology dictionary with over 60,000 biology terms. It uses the wiki concept, so that anyone can make a contribution.


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Voltage is a representation of the electric potential energy per unit charge. If a unit of electrical charge were placed in a location, the voltage indicates the potential energy of it at that point. In other words, it is a measurement of the energy contained within an electric field, or an electric circuit, at a given point.


voltage-gated ion channel Any ion channel that opens and closes in response to changes in electrical potential across the cell membrane in which the channel is situated. There are several types of voltage-gated channel, each allowing the selective passage of a particular ion. Source for information on voltage-gated ion channel: A Dictionary of Biology dictionary.


threshold [thresh´old] 1. the level that must be reached for an effect to be produced, as the degree of intensity of stimulus that just produces a sensation. 2. that value at which a stimulus just produces a sensation, is just appreciable, or comes just within the limits of perception. 3. renal t. auditory threshold the slightest perceptible sound ...


resistance [re-zis´tans] 1. opposition, or counteracting force, as opposition of a conductor to passage of electricity or other energy or substance. 2. the natural ability of a normal organism to remain unaffected by noxious agents in its environment; see also immunity. 3. in psychology or psychiatry, conscious or unconscious defenses against change ...


Ion channel: Ion channel, protein expressed by virtually all living cells that creates a pathway for charged ions from dissolved salts, including sodium, potassium, calcium, and chloride ions, to pass through the otherwise impermeant lipid cell membrane. Operation of cells in the nervous system, contraction of


Voltage is the electromotive force or the electric potential energy difference between two points (often within the context of an electrical circuit) per unit of charge, expressed in volts (V). Voltage, along with current and resistance, is used to describe the behavior of electrons.


Hyperpolarization is a change in a cell's membrane potential that makes it more negative. It is the opposite of a depolarization.It inhibits action potentials by increasing the stimulus required to move the membrane potential to the action potential threshold.. Hyperpolarization is often caused by efflux of K + (a cation) through K + channels, or influx of Cl – (an anion) through Cl ...


Other articles where Threshold potential is discussed: nervous system: Localized potential: …reaches what is called the threshold potential, it triggers the nerve impulse, or action potential see below. If it does not reach that amplitude, then the neuron remains at rest, and the local potential, through a process called passive spread, diffuses along the nerve fibre and back out through the…