nucleoplasmic (nukleoplazmik)

[ nucleospindle (nūklē-ō-spin"dl), n. [ cleus, a kernel, + E. spindle.] The nucleus spindle; a fusiform figure occurring in karyokinesis, formed of striated achromatin figures, and often bearing pole-stars at each pole. nucleus (nūklē-us), n.; pl. nuclei (-1). [L. nucleus, a little nut, a kernel, the stone of a fruit, for * nucule us (cf. equiv. nucula, dim. of пих (пис-), a nut. Not related to E. nut.] 1. A kernel; hence, a central ma about which matter is collected, or to which accretion is made; any body or thing that serves as a center of aggregation or a emblage; mblage; figuratively, something existing as an initial or focal point or aggregate: as, a nucleus of truth; a nucleus of civilization. aggregation IMG:content-1492.png:[blocks in formation] (a) In biol ., the kernel of a cell, in general; a central or interior differentiated ma of protoplasm, found in nearly all cells, vegetable or animal, and consisting of an oval or rounded body composed of (1) a nuclear membrane, (2) nuclear network, and (3) nucleoplasm, and containing nucleoli. The nuclear network is made up of threads or fibrils which are composed of a deeply staining part, "chromatin," and a feebly staining intermediate substance, "linin" or para chromatin (nucleohyaloplasm). In the meshes of the network is found the more fluid part of the nucleus, the nucleoplasm (achromatin, karyochylema, para linin). Nucleoplasm, according to Carnoy, consists of a plast in network and a granular fluid, "enchylema." The nuclear membrane is considered by some observers to be an inner limiting layer of cell-protoplasm surrounding the nucleus, by others to be a condensation of the peripheral portion of the nuclear network. There may be but one nucleus or several nuclei in one cell; and a nucleus may be nucleolate or not. Nuclei are generally proportionate in size to the cell containing them; in some instances, however, they form almost the entire cell-ma . A structural difference between the nucleus and the rest of the cell-protoplasm is indicated by its greater resistance to powerful reagents, and by its varied reaction with stains. Functionally, the nucleus is the most important portion of the cell, as it is here that the complex series of changes known as karyokinesis take place, resulting in the division of the nucleus and followed by the division of the cell. This proce of mitosic or indirect cell-division is found in all varieties of cells, whether vegetable or animal, fetal or adult, normal or pathological. Instances of cell-division not mitosic have, however, been noted. The nucleus of the human ovum was discovered by Purkinje in 1825, and hence is often called the corpuscle of Purkinje . Its usual name in text-books of anatomy is germinal vesicle. See cut under cell , 5. (b) In zool .: (1) In ascidians, the alimentary and reproductive viscera collectively, when these are aggregated into a ma , as in the salps. (2) In protozoans, a solid rod-like or strap-shaped body, having in many cases the functions of an ovary in connection with a nucleolus (see nucleolus , 2). (3) In echinoderms, the madre por i form body. (c) In an at., a collection of ganglion-cells in the brain or other portion of the cerebrospinal axis. (d) In conch ., the embryonic shell which remains at the apex of the mature shell, as of a gastropod; also, the initial point from which the operculum of a gastropod grows. See pro to conch. (e) A body having a stronger or weaker attraction for the gas, vapor, or salt of a solution than for the liquid part of it, and therefore modifying by its presence the freezing and boiling-points. Ro iter. (f) In astron ., the bright central point usually present in the head of a comet and often in a nebula. 2. [ cap .] A genus of gastropods: same as Columbella. Fabric i us , 1822. - Acce ory auditory nucleus, the group of ganglion-cells situated at the junc tion of the lateral and median roots of the auditory nerve. Also called anterior auditory nucleus , lateral nucleus of the medial root, ganglion of the auditory nerve , nucleus acce o rius acustici, and nucleus cochlear is . - Amygdaloid nucleus. Same as amygdala , 4.-Caudate nucleus. See caudate . Cervical nucleus, a group of ganglion-cells opposite the origin of the roots of the third and fourth 4035 cervical nerves, and corresponding in position to Clarke's column. - Clavate nucleus. See clavatel. External acce ory olivary nucleus, a short band of gray matter in the reticular is grise a, just dorsad of the nucleus olivaris. Also called superior or lateral acce ory olivary nucleus. Inferior auditory nucleus, that part of the acce ory nucleus which lies between the two auditory roots.Inner acce ory olivary nucleus, an elongated collection of gray matter lying just behind the pyramid and to the inner ventral side of the (lower) olive. Also called anterior acce ory olivary nucleus and pyramidal nucleus. - Lenticular nucleus. See lenticular. Nuclei arcuati, small collections of gray matter near the ventral surface of the pyramid, beneath and among the external arcuate fibers. The largest group forms the nucleus arcuatus triangular is, or nucleus arciform is, or nucleus pyramidal is anterior. Also called nuclei of the superficial arcuate fibers. - Nuclei lemnisci medial is, small groups of ganglion-cells in the immediate vicinity of the lemniscus medial is. - Nucleus abducent is, the nucleus of origin of the abducens nerve, a round ma of gray matter in the lower part of the pons, near the floor of the fourth ventricle and not far from the middle line. - Nucleus ambiguus, a tract of large ganglion-cells in the subs tanti a reticular is grise a of the oblong at a. It furnishes fibers to the vagus and glo opharyngeus; other fibers from it turn toward the raphe. It is continued upward as the facial nucleus. Also called nucleus lateral is medius. Nucleus amygdale, a rounded gray ma continuous with the cortex of the tip of the gyrus hippocampi, projecting into the end of the descending cornu of the lateral ventricle. Also called amygdala and amygdaloid tubercle. - Nucleus anterior thalami, the gray matter of separated the thalamus from the corresponding inner and outer to the nuclei anterior by tubercle, septa of white matter. Also called nucleus superior thalami, nucleus of the anterior tubercle, and nucleus caudatus thalami. - Nucleus bulb i fornicis, the gray matter within a corpus albicum.-Nucleus caudatus, the caudate nucleus, the upper ganglion of the corpus striatum, separated from the lenticular nucleus by the internal capsule. Also called the intraventricular ganglion of the striate body. Nucleus central is inferior, a group of ganglion-cells in the subs tanti a alba of the upper part of the oblong at a and lower the pons, between lemniscus posterior longitudinal fasciculus, on both sides of the middle line. Also called nucleus central is of Roller. - Nucleus central is superior, a collection of ganglion-cells in the tegmentum of the upper part of the pons, on either side of the middle line and between the posterior longitudinal fasciculus and the decu ation of the superior peduncles of the cerebellum. - Nucleus cuneatus extern us, a small separate gray ma external to the principal nucleus funiculi cuneati. - Nucleus dentatus. Same as corpus dentatum (a) (which see, under corpus ). - Nucleus dentatus cerebelli, the convoluted shell of gray matter lying in the white substance of either hemisphere of the cerebellum, and open on its median side. Also called corpus dentatum cerebelli, nucleus denticulatus, nu cleus fimbriatus, nucleus lenticulatus, corpus ciliare, corpus rhomboideum, and corpus rhomboi dale. - Nucleus emboli form is, a clavate ma of gray substance lying mesially to and partially covering the hilum of the nucleus dentatus cerebelli. Also called embolus. - Nucleus extern us thalami, the gray matter of the outer part of the thalamus, extending posteriorly into the pulvinar, and separated from the inner nucleus by the lamina medullar is medial is. Also called nucleus lateral is thalami. - Nucleus funiculi anterior is, a group of large ganglion-cells lying on the median side of the hypoglo al roots, at about the middle of their course through the oblong at a. Also called nucleus of anterior root-zone. Nucleus funiculi cuneati, the body of gray matter with ganglion-cells in the upper end of the cuneate funiculus. Also called cuneate nucleus and restiform nucleus. - Nucleus funiculi lateral is, the separated part of the anterior cornu of the spinal cord continued into the oblong at a, lying in the lateral column near the surface, behind the olivary nucleus. Also called nucleus anterolateralis, nucleus lateral is. - Nucleus funiculi teretis, a tract of fusiform ganglion-cells lying close to the middle line and close to the surface in the funiculus teres of the floor of the fourth ventricle. Also called nucleus medial is. - Nucleus globosus, a small round ma of gray matter between the nucleus emboli form is and the nucleus tecti. - Nucleus intern us thalami, the gray matter of the inner part of the thalamus, separated from the outer and anterior nuclei by septa of white matter. The internal nuclei of the two sides are united by the middle commi ure. Also called nucleus medial is thalami. Nucleus lateral is. ( a ) The nucleus funiculi lateral is. (b) Same as claustrum , 1. - Nucleus lemnisci lateral is, a collection of ganglion-cells in the tegmental region of the upper part of the pons, close to the lateral surface, giving fibers to the lateral lemniscus. - Nucleus lenticular is, the lenticular nucleus, the lower layer nucleus of the corpus striatum, divided by medullary lam inæ into three zones, the outer of which is called the putamen, while the two inner are called the globus pallid us. Also called the extra ventricular ganglion of the striate body and nucleus lentiform is. Nucleus of Bechterew, the ill-defined group of ganglion-cells lying dorsad of Deiters's nucleus, from which it is claimed by Bechterew that some of the fibers of the medial root of the auditory nerve arise. Also called nucleus angular is, principal nucleus of the nervus vestibular is, and nucleus vestibular is. Nucleus of Deiters, a ma of gray matter containing large cells lying on the inner side of the restiform body, and giving origin to the medial root of the auditory nerve. Also called outer auditory nucleus, ascending root, medial nucleus of the me dial root, and lateral part of the nucleus superior. - Nucleus of Luys, an almond-shaped gray ma with pigmented ganglion-cells in the regio sub thalamic a. Also called corpus sub thalami cum, Luys's body, nucleus amygdal i form is, and nucleus pedunculi cerebri. Nucleus of Pander, the expanded extremity of the white yolk of an egg, beneath the blastoderm. - Nucleus olivaris superior, a convoluted plate of gray matter lying dorsad of the trapezium, not prominent in man. It appears to be connected with the acce ory auditory nucleus of the opposite and to a le degree of the same side through the trapezium, with the poste rior quadrigeminal body of the same side through the lateral lemniscus, and also with the abducens nucleus of the same side. Also called nucleus dentatus partis commi u nude ralis, and upper or superior olivary body or olive. - Nucleus pont is, or, in the plural, nuclei pont is, gray matter with numerous small nerve-cells included between the fibers of the ventral or crustal part of the pons. - Nucleus reticular is tegmenti pont is, an a emblage of scattered ganglion-cells in the pons, on both sides of the raphe, between the lemniscus and the posterior longitudinal fasciculus, and cerebral ward from the nucleus central is inferior. - Nucleus tecti, a small ma of gray matter in the white center of the anterior part of the vermis of the cerebellum, close to the median line on either side. Also called roof - nucleus, nucleus fastigii, and subs tanti a ferruginea superior. - Nucleus trapezii, ganglion-cells scattered among the fibers of the trapezium. Also called nu cleus trapezoides. Principal auditory nucleus, a gray ma of triangular cro -section, forming a prominence on the floor of the fourth ventricle (tuberculum acusticum). The str iæ medulla res pa over it. Also called central, in. ner, or posterior nucleus, median nucleus of the lateral root, and median portion of the nucleus superior. - Pyramidal nucleus, the inner acce ory olivary nucleus. - Red nucleus, a ma of gray matter with numerous large pig mented cells in the tegmentum of the crus cerebri. To it the superior cerebellar peduncle of the opposite side proceeds. Also called nucleus of the tegmentum, nucleus tegmenti, and tegmental nucleus. - Restiform nucleus. Same as nucleus funiculi cuneati. [NL., nucula , a