Nucleus

(nu’-kle-us) [nucleus, from nux, nut]. I. The e ential part of a typic cell, usually round in outline, and situated near the center. 2. The center around which the ma of a crystal aggregates. 3. The central element in a compound, as the carbon in hydrocarbons. 4. A collection of gray matter in the central nervous system having a distinct function. 5. The deep origin of a nerve. N. ambiguus, N., Anterior, a collection of nerve-cells near the N. of the vagus.29 N. amygdalae, an irregular aggregation of gray matter situated at the apex of the temporal lobe of the brain, between it and the apex of the middle ventricular horn. N. of Bechterew, an ill-defined group of ganglion-cells lying dorsad of Deiters’ nucleus, and supposed to give origin to some of the fibers of the middle root of the auditory nerve. It is also called the N. vestibular is. N., Burdach’s. See N. funiculi cuneati. N., Caudal. See N., Oculomotor. N., Caudate, the intraventricular part of me corpus striatum. N. cinereus, a term sometimes used to designate the gray substance of the restiform bodies. N., Cleavage-. Synonym of N., Segmentation-. N., Daughter-. See Mitosis. N. emboli form is, a small ma of gray matter situated in the interval between the N. dentatus and N. fastigii, and lying nearer the former. N. fastigii, a flat expanse of gray matter on each side of the inferior vermiform proce of the cerebellum directly over the roof of the fourth ventricle. N. fimbriatus. Synonym of Corpus.dentation. N. funiculi cuneati, a ma of gray matter of the posterior column of the medulla, lying beneath the funiculus cuneatus. N. funiculi gracilis, an elongated club-shaped ma of gray matter in the mesal portion of the posterior column of the medulla. N., Germinal, the N. resulting from the union of the male and female pronuclei. NM Gingival, a part of the cerebellum in the fetus (between the third and fourth months), which bears some resemblance to the gums. N., Globic, N. globosus, the globulus, a number of small round or oval ma es of gray matter situated in the interval between the N. dentatus and N. fastigii, lying near to, and probably an acce ory detachment of the latter. N. gracilis, a column of gray matter in the posterior pyramid of the medulla oblong at a. N., Gray, the gray matter of the spinal cord. N., Intraventricular, the caudate nucleus. N., Kolliker’s, the gray matter surrounding the canal of the spinal cord. N., Laryngeal, the nucleus of origin of the nerve-fibers of the larynx. N., Lenticular, N. lentiform is, the extra ventricular portion of the corpus striatum, lying between the internal and external capsules. N. of Luys, an almond-shaped ma of gray matter with pigmented ganglion cells in the sub thalamic region. N. mag no cellular is, Deiters’ nucleus; a nucleus of gray matter in the medulla oblong at a, situated mesad of the restiform column at the level of entry of the auditory nerve-roots. N., Mother-. See Mother-star, under Karyokinesis. N., Motor, a collection of nerve cells in the central nervous system giving origin to a motor nerve. N., Oculomotor, the nucleus of the oculomotor nerve, lying dorsad of the posterior longitudinal bundle, under the aqueduct of Sylvius. N., Olivary, a folded ma of gray matter in the medulla oblong at a, producing a swelling on the surface, the olivary body. N. of Origin, the collection of ganglion-cells in the central nervous system giving origin to a nerve. N. pyramidal is, the inner acce ory olivary nucleus. N., Red. See N. tegmenti. N., Restiform, the gray matter of the restiform body. N., Segmentation-, the N. that appears shor after the fusion of the male and female pronuclei the; last step in the proce of fertilization;it is so called because within it cleavage is first established. N., Spermatic. Synonym of the male pronucleus. N., Selling’s. Synonym of N. teg??ienti. N., Sub ependymal, the internal nucleus of the ei or auditory nerve, lying just beneath the ependyma of the fourth ventricle. N., Tegmental, N. tegmenti, red N.; a ma of reticular substance in the tegmentum of the crus cerebri, to the inner side of the subs tanti a nigra. N., Vesicular, a rather large cell-nucleus, the membrane of which stains deeply, while the central portion remains relatively pale. N. vestibular is. See N. of Bechterew. N., Vitelline, a nucleus resulting from the fusion of the male and female pronuclei within the vitellus. N., Westphal’s, the N. of origin of a part of the trochlear fibers; it is situated posteriorly to the trochlear nucleus proper. N., White, the white substance of the dentate body of the olive. Nuel’s Space. A triangular space between the outer hair-cells and the outer rods of Corti of the internal ear. 452