nerve impulse

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impulse

 [im´puls]
1. a sudden pushing force.
2. a sudden uncontrollable determination to act.
cardiac impulse a heartbeat palpated over the left side of the chest at the apex of the heart. See also point of maximal impulse.
impulse control disorders a group of mental disorders characterized by repeated failure to resist an impulse to perform some act harmful to oneself or to others. In spite of the act's being socially unacceptable or inconsistent with the rest of the person's personality or lifestyle, he or she feels pleasure or emotional release upon doing it. Disorders in this category include intermittent explosive disorder, kleptomania, pathological gambling, pyromania, and trichotillomania.
nerve impulse the electrochemical process propagated along nerve fibers.

nerve impulse

n.
A wave of physical and chemical excitation along a nerve fiber in response to a stimulus, accompanied by a transient change in electric potential in the membrane of the fiber.

nerve impulse

See impulse.

nerve impulse

The wave-like progression of electrical depolarization that passes along a stimulated nerve fibre. The nerve impulse results from a movement of positive and negative ions across the membrane of the fibre.

nerve impulse

the message conducted along the AXON of a NERVE (1). The impulse is a propagated negative charge on the outside of the membrane which results from a wave of DEPOLORIZATION passing along an axon. The RESTING POTENTIAL is reversed and becomes an ACTION POTENTIAL, and this passes down the axon at between 1 and 100 ms, depending on the diameter of the fibre, the presence of a MYELIN SHEATH, temperature, species of animal etc. Once an impulse is initiated it progresses without degeneration, and the strength or nature of the stimulus does not affect it; it either is generated or it is not (ALLORNONE LAW). Varying stimuli produce varying numbers of impulses (see SUMMATION). After each impulse there is a REFRACTORY PERIOD during which a second impulse may not pass.

impulse

1. a sudden pushing force.
2. a sudden uncontrollable act.
3. a nerve impulse.

cardiac impulse
movement of the chest wall caused by the heartbeat. Called also apex beat.
nerve impulse
the electrochemical process propagated along nerve fibers.
References in periodicals archive ?
In nerve cells, ion channels work with extreme precision: Sodium channels open for a fraction of a second to allow just enough sodium in to trigger a nerve impulse.
The sequence includes nerve impulses in the brain, spinal column, and area around the penis, and response in muscles, fibrous tissues, veins, and arteries in and near the corpora cavernosa.
Nerve impulses that seem slower or weaker than usual indicate possible damage.
Myasthenia gravis is caused by a defect in the transmission of nerve impulses to muscles.
In one study, researchers at Purdue University in Lafayette, IN found a single injection of polyethylene glycol restored nerve impulses and skin reflexes in guinea pigs with crush-type spinal injuries.
In Bryant's case, any challenge fires up his nerve impulses so his cerebellum lights up like a telephone switchboard.
Our neuromuscular system is constantly sending and receiving messages in the form of nerve impulses.
scleroses, or lesions) which further interrupts the conduction of nerve impulses (Rumrill, Kaleta, & Battersby, 1996).
A muscle is a tissue composed of bundles of specialized cells that, when stimulated by nerve impulses, contract and produce movement.
Those who believe they have the illness have up to 25 percent lower levels of the brain chemical N-acetyl-aspartate in the brain stem and basal ganglia which are switching stations for reflexes and nerve impulses that govern movement, memory, and emotion.
Organophosphates act primarily by inhibiting an enzyme which plays a major role in the transmission of nerve impulses.
Pigs brains are being examined using specialist equipment, to find a protein which converts chemicals into nerve impulses.