| special visceral efferent nuclei | Collective term for those motoneuronal nuclei of the brainstem (n. Ambiguus, facial motor nucleus, motor nucleus of the trigeminus) that develop from the branchiomotor column of the embryo and innervate striated muscle fibres (muscles of mastication, facial musculature, pharynx and vocal cord muscles) developed from the mesenchyme of the branchial arches. Synonym: special visceral efferent nuclei, special visceral motor nuclei. (05 Mar 2000) |
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| special visceral motor nuclei | Collective term for those motoneuronal nuclei of the brainstem (n. Ambiguus, facial motor nucleus, motor nucleus of the trigeminus) that develop from the branchiomotor column of the embryo and innervate striated muscle fibres (muscles of mastication, facial musculature, pharynx and vocal cord muscles) developed from the mesenchyme of the branchial arches. Synonym: special visceral efferent nuclei, special visceral motor nuclei. (05 Mar 2000) |
| first visceral cleft | <anatomy> The cleft between the hyoid and mandibular arches of the embryo; the external auditory meatus is developed from its dorsal portion. Synonym: first visceral cleft. (05 Mar 2000) |
| larva migrans, visceral | A condition produced in man by the prolonged migration of animal nematode larvae in extraintestinal tissues other than skin; characterised by persistent hypereosinophilia, hepatomegaly, and frequently pneumonitis, commonly caused by toxocara canis and toxocara cati. (12 Dec 1998) |
| leishmaniasis, visceral | A chronic disease caused by leishmania donovani and transmitted by the bite of several sandflies of the genera phlebotomus and lutzomyia. It is commonly characterised by fever, chills, vomiting, anaemia, hepatosplenomegaly, leukopenia, hypergammaglobulinaemia, emaciation, and an earth-gray colour of the skin. The disease is classified into three main types according to geographic distribution: indian, mediterranean (or infantile), and african. (12 Dec 1998) |
| abdominocardiac reflex | Mechanical stimulation (usually distention) of abdominal viscera causing changes (usually a slowing) in the heart rate or the occurrence of extrasystoles. (05 Mar 2000) |
| Abrams' heart reflex | A contraction of the myocardium when the skin of the precordial region is irritated. (05 Mar 2000) |
| accommodation reflex | Increased convexity of the lens, due to contraction of the ciliary muscle and relaxation of the suspensory ligament, to maintain a distinct retinal image. (05 Mar 2000) |
| Achilles reflex | A contraction of the calf muscles when the tendo calcaneus is sharply struck. Synonym: ankle jerk, ankle reflex, tendo Achillis reflex, triceps surae reflex. (05 Mar 2000) |
| acousticopalpebral 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) |
| acquired 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) |
| acromial reflex | Contraction of the biceps muscle caused by a tap on the acromion or the coracoid process. (05 Mar 2000) |
| acute reflex bone atrophy | Atrophy of bones, commonly of the carpal or tarsal bones, following a slight injury such as a sprain. See: causalgia, reflex sympathetic dystrophy. Synonym: acute reflex bone atrophy, posttraumatic osteoporosis, Sudeck's syndrome. Origin: L. English sweat (05 Mar 2000) |
| adductor reflex | Contraction of the adductors of the thigh caused by tapping the tendon of the adductor magnus muscle while the thigh is abducted. (05 Mar 2000) |
| anal reflex | Contraction of the internal sphincter gripping the finger passed into the rectum. (05 Mar 2000) |