apex impulse |
Conventionally the lowermost, leftmost area of cardiac pulsation that is usually palpable. (05 Mar 2000) |
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cardiac impulse |
Movement of the chest wall produced by cardiac contraction. (05 Mar 2000) |
morbid impulse |
An impulse that drives one to commit some act, usually of a deviant or forbidden nature, notwithstanding efforts to restrain oneself. (05 Mar 2000) |
point of maximal impulse |
The point on the chest wall at which the maximal cardiac impulse is seen and/or felt. (05 Mar 2000) |
nerve impulse |
An action potential. (18 Nov 1997) |
impulse |
1. The act of impelling, or driving onward with sudden force; impulsion; especially, force so communicated as to produced motion suddenly, or immediately. "All spontaneous animal motion is performed by mechanical impulse." (S. Clarke) 2. The effect of an impelling force; motion produced by a sudden or momentary force. 3. <mechanics> The action of a force during a very small interval of time; the effect of such action; as, the impulse of a sudden blow upon a hard elastic body. 4. A mental force which simply and directly urges to action; hasty inclination; sudden motive; momentary or transient influence of appetite or passion; propension; incitement; as, a man of good impulses; passion often gives a violent impulse to the will. "These were my natural impulses for the undertaking." (Dryden) Synonym: Force, incentive, influence, motive, feeling, incitement, instigation. Origin: L. Impulsus, fr. Impellere. See Impel. Source: Websters Dictionary (01 Mar 1998) |
impulse control disorder |
A class of mental disorder's characterised by an individual's failure to resist an impulse to perform some act harmful to himself or to others; includes pathological gambling, pedophilia, kleptomania, pyromania, trichotillomania, intermittent and isolated explosive disorder's. (05 Mar 2000) |
impulse control disorders |
Disorders whose essential features are the failure to resist an impulse, drive, or temptation to perform an act that is harmful to the individual or to others. Individuals experience an increased sense of tension prior to the act and pleasure, gratification or release of tension at the time of committing the act. (12 Dec 1998) |
irresistible impulse |
A compulsion to act such that one feels or claims it cannot be resisted. (05 Mar 2000) |
ectopic impulse |
An electrical impulse from an area of the heart other than the sinus node. (05 Mar 2000) |
escape impulse |
One or more impulse's (atrial, junctional, or ventricular) arising as a result of delay in the formation or arrival of impulses from the prevailing pacemaker. (05 Mar 2000) |
Abbe theory of image formation |
<optics, physics> Abbe's theory is based on the fact that a non-self-luminous particle, which is illuminated by an extraneous source, gives rise to diffracted light rays, in addition to the dioptric pencil. He stated that to form a good microscopical image as many of the diffracted rays as possible should be intercepted by the objective. With closely ruled lines, his theory is easily demonstrated by observing the back lens of the objective, for here the diffracted rays can be observed directly if the aperture diaphragm is closed. It can be shown that, when the illumination is arranged to exclude the diffracted images, resolution is lost. (11 Mar 1998) |
reaction formation |
In psychoanalysis, a postulated defense mechanism in which attitudes and behaviours that are adopted are the opposites of that which the individual would ordinarily be expected to express and actually feel at an unconscious level. (05 Mar 2000) |
pattern formation |
<cell biology> One of the classic problems in developmental biology is the way in which complex patterns are formed from an apparently uniform field of cells. Various hypotheses have been put forward and there is now evidence for the existence of gradients of diffusible substances (morphogens) specifying the differentiative pathway that should be followed according to the concentration of the morphogen around the cell. (18 Nov 1997) |
reticular formation |
<anatomy, neurology> A region extending from the pons & medulla oblongata through the mesencephalon, characterised by a diversity of neurons of various sizes and shapes, arranged in different aggregations and enmeshed in a complicated fibre network. (12 Dec 1998) |