| auditory reflex | Any reflex occurring in response to a sound, e.g., cochleopalpebral reflex. (05 Mar 2000) |
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| auricular reflex | A movement of the ears in animals in response to a sound; part of the investigatory reflex. (05 Mar 2000) |
| auriculopalpebral reflex | Closure of the eye in response to stimulation of the skin at the depth of the external auditory meatus. Synonym: auriculopalpebral reflex. (05 Mar 2000) |
| auriculopressor reflex | Peripheral vasoconstriction and a rise in blood pressure in response to a fall in pressure in the great veins. Synonym: Pavlov's reflex. (05 Mar 2000) |
| auropalpebral reflex | A form of the wink reflex in which there is a contraction, sometimes very slight, of the orbicularis palpebrarum muscle when a sudden noise is made close to the ear; it is absent in labyrinthine disease with total deafness. Synonym: acousticopalpebral reflex, auropalpebral reflex, cochleo-orbicular reflex, startle reflex. (05 Mar 2000) |
| axon reflex | An effect brought about by the passage of the nerve impulses from a sensory ending to the effector organ along divisions of the nerve fibre without traversing a synapse, e.g., as in the vasodilation resulting from stimulation of the skin or the irritation of the conjunctiva; the reaction occurs even when the nerve fibre has been sectioned and thus isolated from the nervous centres. (05 Mar 2000) |
| Babinski reflex | <clinical sign> Extension of the great toe and abduction of the other toes instead of the normal flexion reflex to plantar stimulation, considered indicative of pyramidal tract involvement ("positive" Babinski). Synonym: Babinski reflex, Babinski's phenomenon, great-toe reflex, paradoxical extensor reflex, toe phenomenon. (05 Mar 2000) |
| back of foot reflex | The foot being firmly supported on its inner side, a sharp tap on the dorsal tendons causes extension of the second to the fifth toes. Synonym: back of foot reflex, dorsum of foot reflex. (05 Mar 2000) |
| Bainbridge reflex | An increase in heart rate caused by a rise in pressure of the blood in the right atrium due to increased flow and/or pressure in the great veins at its entrance. (05 Mar 2000) |
| Barkman's reflex | Contraction of the ipsilateral rectus muscle in response to a stimulus applied to the skin below a nipple. (05 Mar 2000) |
| basal joint reflex | Opposition and adduction of the thumb with flexion at its metacarpophalangeal joint and extension at its interphalangeal joint, when firm passive flexion of the third, fourth, or fifth finger is made; the reflex is present normally but is absent in pyramidal lesions. Synonym: finger-thumb reflex, Mayer's reflex. (05 Mar 2000) |
| Bechterew-Mendel reflex | Percussion of the dorsum of the foot causes flexion of the toes; present in a pyramidal lesion. Synonym: dorsum pedis reflex, Mendel-Bechterew reflex. (05 Mar 2000) |
| behaviour reflex | A reflex that is gradually developed by training and association through the frequent repetition of a definite stimulus. See: conditioning. Synonym: acquired reflex, behaviour reflex, trained reflex. (05 Mar 2000) |
| Benedek's reflex | <neurology, physiology> Plantar flexion of the foot by tapping the anterior margin of the lower part of the fibula, while the foot is slightly dorsiflexed. (05 Mar 2000) |
| Bezold-Jarisch reflex | A reflex with afferent and efferent pathways in the vagus, originating in unidentified chemoreceptors in the heart and resulting in sinus bradycardia, hypotension, and probable peripheral vasodilation. (05 Mar 2000) |