| dorsal accessory olivary nucleus | A detached part of the olivary nucleus dorsal to the latter's main body. Synonym: nucleus olivaris accessorius dorsalis. (05 Mar 2000) |
|---|---|
| dorsal motor nucleus of vagus | The visceral motor nucleus located in the vagal trigone (ala cinerea) of the floor of the fourth ventricle. It gives rise to the parasympathetic fibres of the vagus nerve innervating the heart muscle and the smooth musculature and glands of the respiratory and intestinal tracts. Synonym: nucleus dorsalis nervi vagi, dorsal motor nucleus of vagus, dorsal nucleus of vagus, dorsal vagal nucleus, nucleus alae cinereae. (05 Mar 2000) |
| dorsal nucleus | A column of large neurons located in the base of the posterior gray column of the spinal cord, extending from the first thoracic through the second lumbar segment; it gives rise to the dorsal spinocerebellar tract of the same side. Synonym: nucleus thoracicus, Clarke's column, Clarke's nucleus, dorsal nucleus, nucleus dorsalis, Stilling's column, Stilling's nucleus. (05 Mar 2000) |
| dorsal nucleus of trapezoid body | A circumscript, bipartite cell group located ventrolaterally in the lower pontine tegmentum, immediately dorsal to the trapezoid body; the nucleus receives fibres from both the ipsilateral and contralateral cochlear nuclei, and contributes fibres to the lateral (auditory) lemniscus of both sides. It is believed to be prominently involved in the function of spatial localization of sound. Synonym: nucleus dorsalis corporis trapezoidei, oliva superior, superior olivary nucleus, superior olive. (05 Mar 2000) |
| dorsal nucleus of vagus | The visceral motor nucleus located in the vagal trigone (ala cinerea) of the floor of the fourth ventricle. It gives rise to the parasympathetic fibres of the vagus nerve innervating the heart muscle and the smooth musculature and glands of the respiratory and intestinal tracts. Synonym: nucleus dorsalis nervi vagi, dorsal motor nucleus of vagus, dorsal nucleus of vagus, dorsal vagal nucleus, nucleus alae cinereae. (05 Mar 2000) |
| dorsal nucleus of vagus nerve | The visceral motor nucleus located in the vagal trigone (ala cinerea) of the floor of the fourth ventricle. It gives rise to the parasympathetic fibres of the vagus nerve innervating the heart muscle and the smooth musculature and glands of the respiratory and intestinal tracts. Synonym: nucleus dorsalis nervi vagi, dorsal motor nucleus of vagus, dorsal nucleus of vagus, dorsal vagal nucleus, nucleus alae cinereae. (05 Mar 2000) |
| dorsal vagal nucleus | The visceral motor nucleus located in the vagal trigone (ala cinerea) of the floor of the fourth ventricle. It gives rise to the parasympathetic fibres of the vagus nerve innervating the heart muscle and the smooth musculature and glands of the respiratory and intestinal tracts. Synonym: nucleus dorsalis nervi vagi, dorsal motor nucleus of vagus, dorsal nucleus of vagus, dorsal vagal nucleus, nucleus alae cinereae. (05 Mar 2000) |
| auditory field | The space included within the limits of hearing of a definite sound, as of a tuning fork. (05 Mar 2000) |
| bright field illumination | <microscopy> The method of lighting the specimen with a solid cone of rays. Transmitted bright field illumination is performed by a substage condenser. Reflected bright field illumination is performed by a vertical illuminator. Compare: dark field illumination (05 Aug 1998) |
| bright field imaging | <microscopy> An imaging mode in a transmission electron microscopy that uses only unscattered Electrons to form the image. Contrast in such an image is due entirely to mass-thickness variations in amorphous samples, and may include diffraction contrast in crystalline samples. (05 Aug 1998) |
| bright field microscopy | <technique> Optical microscopy, in which absorption to a great extent and diffraction to a minor extent give rise to the image, as opposed to phase contrast or interference methods of microscopy. (18 Nov 1997) |
| Broca's field | The posterior part of the inferior frontal gyrus of the left or dominant hemisphere, corresponding approximately to Brodmann's area 44; Broca identified this region as an essential component of the motor mechanisms governing articulated speech. Synonym: Broca's area, Broca's field, motor speech centre. (05 Mar 2000) |
| cardioid dark field condenser | <microscopy> A condenser designed with two reflecting surfaces, the first, a spherical surface which reflects the rays to a second, cardioid (heart-shaped) surface. The virtue in such an arrangement is that, if the cardioid surface is of true figure, the lens is both achromatic and aplanatic. It has a limiting numerical aperture of about 1.0. Thus objectives of a greater numerical aperture cannot be used successfully with it. A true cardioid figure is the trace of a point on the circumference of a circle rolling around an equal, fixed circle. (05 Aug 1998) |
| magnetic field | The sphere of influence of a magnet. (05 Mar 2000) |
| magnetic field gradient | In magnetic resonance imaging, a magnetic field that varies with location, superimposed on the uniform field of the magnet, to alter the resonant frequency of nuclei and allow recovery of their spatial position. Synonym: field gradient. (05 Mar 2000) |