1 A badge or insignia consisting of stripes meeting at an angle, worn on the sleeve of a military or police uniform to indicate rank, merit, or length of service. 2  n. Heraldry A device shaped like an inverted V.  n.
In physiology, a stimulus (plural stimuli) is a detectable change in the internal or external environment. The ability of an organism or organ to respond to external stimuli is called sensitivity.When a stimulus is applied to a sensory receptor, it normally elicits or influences a reflex via stimulus transduction.ne internal stimulus that causes hormone release is blood pressure. Hypotension, or low blood pressure, is a large driving force for the release of vasopressin, a hormone which causes the retention of water in the kidneys.
Usually, the conditioned stimulus (CS) is a neutral stimulus (e.g., the sound of a tuning fork), the unconditioned stimulus (US) is biologically potent (e.g., the taste of food) and the unconditioned response (UR) to the unconditioned stimulus is an unlearned reflex response (e.g., salivation).lassical conditioning differs from operant or instrumental conditioning: in classical conditioning, behavioral responses are elicited by antecedent stimuli, whereas in operant conditioning behaviors are strengthened or weakened by their consequences (i.e., reward or punishment).