impulsions

Impulsions are the plural form of impulsion and refer to instances of impulse. In English usage, the term appears mainly in physics and physiology, where it denotes short-duration events that produce a change or signal. In physics, an impulsion describes a brief force applied to an object, while in physiology it refers to nerve impulses, the rapid signals that travel along neurons.

In physics, the impulse can be defined as the integral of force over the time interval during which it acts: J = ∫ F dt. The units are newton-seconds (N·s). The impulse–momentum theorem states that the impulse equals the change in momentum (Δp = J). The magnitude of an impulsion depends on both the strength of the force and the duration of its action; a large force for a short time can produce the same impulse as a smaller force over a longer time.

In physiology, nerve impulses are electrochemical signals that propagate along neurons. They arise from transient changes in membrane potential called action potentials, driven by the movement of ions such as sodium and potassium across the cell membrane. Impulses travel along axons, often more rapidly in myelinated fibers through saltatory conduction, and they underlie movement, sensation, and various neural processes.

In everyday language, impulsions may refer to sudden urges or motivations, though this sense is less common in technical writing. The term impulsion is sometimes used as an alternative to impulse, especially in translations from French, but impulse remains the standard term in most scientific contexts.