impulse

1. A sudden pushing or driving force. 2. A sudden, often unreasoning, determination to perform some act. 3. The action potential of a nerve fiber. [L. im-pello, pp. -pulsus, to push against, impel (inp-)]

- apex i. conventionally the lowermost, leftmost area of cardiac pulsation that is usually palpable.

- cardiac i. movement of the chest wall produced by cardiac contraction.

- ectopic i. an electrical i. from an area of the heart other than the sinus node.

- escape i. one or more impulses (atrial, junctional, or ventricular) arising as a result of delay in the formation or arrival of impulses from the prevailing pacemaker.

- irresistible i. a compulsion to act such that one feels or claims it cannot be resisted.

- morbid i. an i. that drives one to commit some act, usually of a deviant or forbidden nature, notwithstanding efforts to restrain oneself.

- right parasternal impulses cardiac activity as palpable or recordable just to the right of the sternum.

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im·pulse 'im-.pəls n

1) a wave of excitation transmitted through tissues and esp. nerve fibers and muscles that results in physiological activity or inhibition

2 a) a sudden spontaneous inclination or incitement to some usu. unpremeditated action <some uncontrollable \impulse...may have driven the defendant to the commission of the murderous act (B. N. Cardozo)>

b) a propensity or natural tendency usu. other than rational <the fundamental \impulse of self-expression (Havelock Ellis)>

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n.

(in neurology) see nerve impulse.

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im·pulse (imґpəls) 1. a sudden pushing force. 2. a sudden uncontrollable determination to act. 3. nerve i.