| white piedra | <microbiology> A fungal infection (tinea albigena) caused by the yeast Trichosporon beigelii that forms light-coloured nodules on the beard and mustache. (13 Nov 1997) |
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| white pine | The dried inner bark of Pinus strobus, used as an ingredient in cough syrups. (05 Mar 2000) |
| white pitch | A resinous exudation from the spruce fir or Norway spruce, Picea excelsa; has been used as a counterirritant in the form of a plaster. Synonym: white pitch. (05 Mar 2000) |
| white pulp | That part of the spleen that consists of nodules and other lymphatic concentrations. (05 Mar 2000) |
| white pupillary reflex | Reflection from a white mass within the eye giving the appearance of a white pupil. Synonym: leukokoria, white pupillary reflex. Origin: Leuko-white, + G. Kore, pupil (05 Mar 2000) |
| white rami communicantes | Short nerves arising from the initial portion of the ventral primary rami of the thoracic and upper lumbar spinal nerves through which all presynaptic sympathetic nerve fibres must pass to reach the sympathetic trunks; also conveyed by the white rami communicans are visceral afferent (sensory) fibres which were conveyed to the sympathetic trunks in splanchnic nerves. Most fibres conveyed by the white rami communicantes are myelinated. Synonym: rami communicantes nervorum spinalium, communicating branches of spinal nerves. (05 Mar 2000) |
| white reaction | The response seen in many individuals after the skin is lightly stroked with a blunt instrument; it is attributed to capillary action. (05 Mar 2000) |
| white soft paraffin | white petrolatum |
| white sponge nevus | An autosomal dominant condition of the oral cavity characterised by soft, white or opalescent, thickened and corrugated folds of mucous membrane; other mucosal sites are occasionally involved simultaneously. Synonym: familial white folded dysplasia, oral epithelial nevus. (05 Mar 2000) |
| white spot | Gray-white or white, rounded or irregularly shaped, slightly opaque patches or spots that are sometimes observed postmortem in the epicardium, especially in middle-aged or older persons; they result from fibrous thickening, and sometimes hyalinization, of the epicardium; similar lesions may also occur in the visceral layer of the peritoneum. Synonym: macula lactea, macula tendinea, tache blanche, tache laiteuse, tendinous spot, white spot. (05 Mar 2000) |
| white spot disease | Small discrete, white, waxy, indurated lesions due to localised degenerative changes in the fibrous tissue. Synonym: white spot disease. (05 Mar 2000) |
| white substance | <anatomy> Brain tissue composed of myelin-coated nerve cell fibres. White matter carries information between the nerve cells in the brain and spinal cord. The inner portion of the cerebrum is composed of white matter. See: grey matter. (13 Nov 1997) |
| white thrombus | A thrombus of opaque dull white colour composed essentially of blood platelets. Synonym: pale thrombus. (05 Mar 2000) |
| white-water | <veterinary> A dangerous disease of sheep. Source: Websters Dictionary (01 Mar 1998) |
| white wax | Yellow wax bleached by being rolled very thin and exposed to the light and air, or bleached by chemical oxidants; same uses as yellow wax. Synonym: bleached wax, white beeswax. (05 Mar 2000) |