| gametic nucleus | <cell biology> The smaller nucleus in ciliate protozoans, fully active in inheritance and passed after meiosis to conjugating pairs. Gives rise to the macronucleus or macronuclei. Genes in the micronucleus are not actively transcribed. (18 Nov 1997) |
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| veins of caudate nucleus | Small veins from the caudate nucleus draining into the superior thalamostriate vein. Synonym: veins of caudate nucleus. (05 Mar 2000) |
| gelatinous nucleus | The soft fibrocartilage central portion of the intervertebral disk; regarded as a derivative of the notochord. Synonym: gelatinous nucleus, nucleus gelatinosus, vertebral pulp. (05 Mar 2000) |
| paracentral nucleus of thalamus | One of the intralaminar nuclei of the thalamus, medial to the central lateral nucleus. Synonym: nucleus paracentralis thalami. (05 Mar 2000) |
| geniculatus lateralis nucleus | The lateral one of a pair of small oval masses that protrude slightly from the posteroinferior aspects of the thalamus; its main (dorsal) subdivision serves as a processing station in the major pathway from the retina to the cerebral cortex, receiving fibres from the optic tract and giving rise to the geniculocalcarine radiation to the visual cortex in the occipital lobe. Synonym: corpus geniculatum laterale, corpus geniculatum externum. (05 Mar 2000) |
| ventrobasal nucleus | The large posterior part of the ventral nucleus of the thalamus receiving the somatic sensory lemnisci (medial lemniscus, spinothalamic tract, trigeminal lemniscus) and the ascending gustatory (taste) lemniscus, and projecting in turn by way of the internal capsule to the cortex of the postcentral gyrus. The nucleus is somatotopically organised and subdivided into a ventral posterolateral nucleus of thalamus representing the leg, a ventral posterior intermediate nucleus of thalamus representing the arm, a ventral posteromedial nucleus of thalamus representing the face, and an arcuate nucleus of thalamus receiving the gustatory lemniscus. Synonym: nucleus ventralis posterior thalami, ventrobasal nucleus. (05 Mar 2000) |
| ventromedial hypothalamic nucleus | <anatomy> A nucleus of the middle hypothalamus, the largest cell group of the tuberal region with small-to-medium size cells. (12 Dec 1998) |
| ventromedial nucleus of hypothalamus | <anatomy> A circumscript ovoid group of small neurons in the medial zone of the tuberal region of the hypothalamus. Bilateral destruction of this nucleus in the rat leads to severe obesity. It receives numerous fibres from the amygdala via the terminal stria; its efferent connections are obscure. Synonym: nucleus ventromedialis hypothalami. (05 Mar 2000) |
| paraventricular hypothalamic nucleus | Nucleus in the anterior part of the hypothalamus. (12 Dec 1998) |
| paraventricular nucleus | A triangular group of large magnocellular neurons in the periventricular zone of the anterior half of the hypothalamus. The cells of the nucleus are similar to those of the supraoptic nucleus; the axons of about 20% of their number join in the formation of the supraopticohypophysial tract and are functionally associated with the posterior lobe of the hypophysis; they project fibres to the brainstem nuclei (dorsal motor nucleus and solitary nucleus) and to the intermediolateral cell column of the spinal cord at thoracic, lumbar, and spinal levels; similar descending autonomic fibres arise from the lateral and posterior hypothalamic nuclei. Synonym: nucleus paraventricularis, filiform nucleus, nucleus filiformis. (05 Mar 2000) |
| germ nucleus | <cell biology> The smaller nucleus in ciliate protozoans, fully active in inheritance and passed after meiosis to conjugating pairs. Gives rise to the macronucleus or macronuclei. Genes in the micronucleus are not actively transcribed. (18 Nov 1997) |
| masticatory nucleus | <anatomy, nerve> A group of motor neurons innervating the muscles of mastication (masseter, temporalis, internal and external pterygoid muscles) and the musculi tensor tympani and tensor veli palatini. The nucleus lies in the upper pontine tegmentum medial to the main sensory nucleus of the trigeminus. Synonym: nucleus motorius nervi trigemini, masticatory nucleus, motor nucleus of trigeminus, nucleus masticatorius. (05 Mar 2000) |
| red nucleus | A distinctive oval nucleus (pink in fresh specimens because of an iron-containing pigment in many of the cells) centrally placed in the upper mesencephalic reticular formation. It receives fibres from the deep cerebellar nuclei and cerebral cortex and projects fibres to the cerebellum, brainstem, spinal cord, and probably to the thalamus. The nucleus is divided into two regions: pars magnocellularis and pars parvocellularis. (12 Dec 1998) |
| vestibular nucleus | One of a group of four main nuclei that includes: the lateral vestibular nucleus (Deiters' nucleus), medial vestibular nucleus (Schwalbe's nucleus), superior vestibular nucleus (Bechterew's nucleus), and inferior vestibular nucleus, located in the lateral region of the hindbrain beneath the floor of the rhomboid fossa. They receive primary fibres of the vestibular nerve, are reciprocally connected with the flocculonodular lobe of the cerebellum, and project by way of the medial longitudinal fasciculus to the abducens, trochlear, and oculomotor nuclei and to the ventral horn of the spinal cord. The lateral vestibular nucleus projects to the ipsilateral ventral horn of the spinal cord by the vestibulospinal tract. Synonym: nucleus vestibularis. (05 Mar 2000) |
| gigantocellular nucleus of medulla oblongata | One of the three major nuclei of the reticular formation of the brainstem. Synonym: nucleus gigantocellularis medullae oblongatae. (05 Mar 2000) |