fastigial nucleus

nucleus /nu·cle·us/ (noo´kle-us) pl. nu´clei   [L.]

1. the central core of a body or object.

2. cell nucleus; a spheroid body within a cell, consisting of a thin nuclear membrane, organelles, one or more nucleoli, chromatin, linin, and nucleoplasm.

3. a group of nerve cells, usually within the central nervous system, bearing a direct relationship to the fibers of a particular nerve.

4. in organic chemistry, the combination of atoms forming the central element or basic framework of the molecule of a specific compound or class of compounds.

5. see atomic n. nu´clear

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ambiguous nucleus  the nucleus of origin of motor fibers of the vagus, glossopharyngeal, and accessory nerves in the medulla oblongata.

anterior olfactory nucleus  scattered groups of neurons intermingled with the olfactory tract that run caudally from the end of the olfactory bulb, some receiving synaptic stimuli from the fibers of the olfactory tract.

arcuate nucleus 

1. a nucleus of nerve cells in the posterior hypothalamic region, extending into the median eminence and almost entirely surrounding the base of the infundibulum.

2. one of the small irregular areas of gray substance on the ventromedial aspect of the pyramid of the medulla oblongata.

atomic nucleus  the central core of an atom, composed of protons and neutrons, constituting most of its mass but only a small part of its volume.

basal nucleus , nucleus basa´lis specific interconnected groups of masses of gray substance deep in the cerebral hemispheres and in the upper brain stem.

nucleus caeru´leus  a compact aggregation of pigmented neurons subjacent to the locus caeruleus, sometimes considered one of the medial reticular nuclei.

nucleus cauda´tus  an elongated, arched gray mass closely related to the lateral ventricle throughout its entire extent, which, together with the putamen, forms the neostriatum.

Nucleus caudatus (caudate nucleus) in a lateral view of the left side of the brain.

central nuclei of thalamus  two small intralaminar nuclei, medial and lateral, situated in the internal medullary lamina.

centromedian nucleus of thalamus  the largest and most caudal of the intralaminar nuclei of the dorsal thalamus.

cochlear nuclei  the nuclei, anterior and posterior, of termination of sensory fibers of the cochlear part of the vestibulocochlear nerve, which partly encircle the inferior cerebellar peduncle at the junction of the medulla oblongata and pons.

cuneate nucleus , nucleus cunea´tus a nucleus in the medulla oblongata, in which the fibers of the fasciculus cuneatus synapse.

Deiters' nucleus  lateral vestibular nucleus; see nuclei vestibulares.

dentate nucleus , nucleus denta´tus the largest of the deep cerebellar nuclei lying in the white matter of the cerebellum.

droplet nuclei  see under infection.

emboliform nucleus , nucleus embolifor´mis a small cerebellar nucleus that lies between the dentate nucleus and globose nucleus and contributes to the superior cerebellar peduncles.

nucleus endopeduncula´ris  a small nucleus in the internal capsule of the hypothalamus, adjacent to the medial edge of the globus pallidus.

fastigial nucleus , nucleus fastigia´tus, nucleus fasti´gii the most medial of the deep cerebellar nuclei, near the midline in the roof of the fourth ventricle.

nucleus gra´cilis  a nucleus in the medulla oblongata, in which the fibers of the fasciculus gracilis of the spinal cord synapse.

hypoglossal nucleus , nucleus of hypoglossal nerve the nucleus of origin of the hypoglossal nerve in the medulla oblongata.

interpeduncular nucleus , nucleus interpeduncula´ris a nucleus between the cerebral peduncles immediately dorsal to the interpeduncular fossa.

lenticular nucleus , lentiform nucleus the part of the corpus striatum just lateral to the internal capsule, comprising the putamen and globus pallidus.

Meynert's nucleus  a group of neurons in the basal forebrain that has wide projections to the neocortex and is rich in acetylcholine and choline acetyltransferase; it undergoes degeneration in paralysis agitans and Alzheimer's disease.

motor nucleus  any collection of cells in the central nervous system giving origin to a motor nerve.

oculomotor nucleus , nucleus oculomoto´rius the origin of the fibers of the oculomotor nerve, situated in the tegmentum of the mesencephalon immediately ventral to the central gray matter, between the medial longitudinal fasciculi. Innervation of the superior rectus of one eye originates in the contralateral oculomotor nerve nucleus; the other elements of the nucleus supply ipsilateral eye muscles via the oculomotor nerve.

olivary nucleus 

1. a folded band of gray substance enclosing a white core and producing the elevation (olive) of the medulla oblongata.

2. olive (2).

nucleus of origin  any of the groups of nerve cells in the central nervous system from which arise the motor, or efferent, fibers of the cranial nerves.

paraventricular nucleus of hypothalamus  a band of cells in the wall of the third ventricle in the anterior hypothalamic region; many of its cells are neurosecretory in function (secreting oxytocin) and project to the neurohypophysis.

pontine nuclei , nu´clei pon´tis groups of nerve cell bodies in the part of the pyramidal tract within the ventral part of the pons, upon which the fibers of the corticopontine tract synapse, and whose axons in turn cross to the opposite side and form the middle cerebellar peduncle.

nucleus pulpo´sus , pulpy nucleus a semifluid mass of fine white and elastic fibers forming the center of an intervertebral disk.

raphe nuclei , nuclei of raphe a subgroup of the reticular nuclei of the brainstem, found in narrow longitudinal sheets along the raphae of the medulla oblongata, pons, and mesencephalon; they include many neurons that synthesize serotonin.

red nucleus  a distinctive oval nucleus (pink in fresh specimens) centrally placed in the upper mesencephalic reticular formation.

reticular nuclei  nuclei found in the reticular formation of the brainstem, occurring primarily in longitudinal columns in three groups: medial or intermediate reticular nuclei, lateral reticular nuclei, and reticular nuclei of the raphe.

nucleus ru´ber  red n.

salivary nuclei  two columns of cells in the posterolateral part of the reticular formation of the pons, together comprising the parasympathetic outflow for the supply of the salivary glands.

sensory nucleus  the nucleus of termination of the afferent (sensory) fibers of a peripheral nerve.

solitary nuclei  any of various nuclei of termination of the visceral afferent fibers of the facial, glossopharyngeal, and vagus nerves, which enter the solitary tract.

subthalamic nucleus , nucleus subthala´micus a nucleus on the medial side of the junction of the internal capsule and crus cerebri.

supraoptic nucleus  one just above the lateral part of the optic chiasm; many of its cells are neurosecretory in function (secreting antidiuretic hormone) and project to the neurohypophysis; other cells are osmoreceptors which respond to increased osmotic pressure to signal the release of antidiuretic hormone by the neurohypophysis.

tegmental nucleus, laterodorsal  several nuclear masses of the reticular formations of the pons and midbrain, especially of the latter, where they are in close approximation to the superior cerebellar peduncles.

terminal nucleus  groups of nerve cells within the central nervous system on which the axons of primary afferent neurons of various cranial nerves synapse.

thoracic nucleus  see under column.

nuclei of trapezoid body  two groups of nerve cell bodies in or next to the trapezoid body.

trigeminal nuclei  four nuclei located along the trigeminal nerve, chiefly in the pons and medulla oblongata.

nu´clei vestibula´res  the four (superior, lateral, medial, and inferior) cellular masses in the floor of the fourth ventricle in which the branches of the vestibulocochlear nerve terminate.

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fastigial nucleus

[fastij′ē·əl]

one of a group of deep cerebellar nuclei that receive input from the medial zone of the cerebellum. It is involved in the control of posture and equilibrium.

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nucleus [noo´kle-us] (pl. nu´clei) (L.)

1. cell nucleus; a spheroid body within a cell, contained in a double membrane, the nuclear envelope, and containing the chromosomes and one or more nucleoli. The contents are collectively referred to as nucleoplasm. The chromosomes contain deoxyribonucleic acid (DNA), which is the genetic material that codes for the structure of all the proteins of the cell.

2. a mass of gray matter in the central nervous system, especially such a mass marking the central termination of a cranial nerve.

3. in organic chemistry, the combination of atoms forming the central element or basic framework of the molecule of a specific compound or class of compounds.

4. the dense core of an atom, made of protons and neutrons held together by the strong nuclear force. Traveling in orbit around it is a cloud of negatively charged particles called electrons. The number of protons in the atomic nucleus gives a substance its identity as a particular element. Called also atomic nucleus. adj., adj nu´clear.

The nucleus and nucleolus of a cell. From Mahon and Manuselis, 2000.

nucleus ambi´guus the nucleus of origin of motor fibers of the glossopharyngeal, vagus, and accessory nerves in the medulla oblongata.

nucleus an´sae lenticula´ris (nucleus of ansa lenticularis) a collection of neurons in the ansa lenticularis as it curves around the medial edge of the globus pallidus.

arcuate nuclei of medulla oblongata, nu´clei arcua´ti medul´lae oblonga´tae small irregular areas of gray substance on the ventromedial aspect of the pyramid of the medulla oblongata.

atomic nucleus nucleus (def. 3).

basal nuclei (nu´clei basa´les) specific interconnected subcortical masses of gray matter embedded in each cerebral hemisphere and in the upper brainstem, comprising the corpus striatum (caudate and lentiform nuclei), amygdaloid body, claustrum, and external, extreme, and internal capsules. Called also basal ganglia.

caudal olivary nucleus a folded band of gray substance enclosing a white core, which produces the elevation on the medulla oblongata known as the olive.

caudate nucleus (nucleus cauda´tus) an elongated, arched gray mass closely related to the lateral ventricle throughout its entire extent, which, together with the putamen, forms the neostriatum.

nucleus ceru´leus a compact aggregation of pigmented neurons lying below the locus ceruleus.

cochlear nuclei, anterior and posterior the nuclei of termination of sensory fibers of the cochlear nerve (see anatomic Table of Nerves in the Appendices); they partly encircle the inferior cerebellar peduncle at the junction of the medulla oblongata and pons.

dentate nucleus (nucleus denta´tus) the largest of the deep cerebellar nuclei, lying in the white matter of the cerebellum just lateral to the emboliform nucleus.

droplet nuclei small particles of pathogen-containing respiratory secretions expelled into the air by coughing, which are reduced by evaporation to small, dry particles that can remain airborne for long periods; one possible mechanism for transmission of infection from one individual to another.

emboliform nucleus (nucleus embolifor´mis) a small cerebellar nucleus lying between the dentate nucleus and the globose nucleus and contributing to the superior cerebellar peduncles.

fastigial nucleus (nucleus fasti´gii) the most medial of the deep cerebellar nuclei, near the midline in the roof of the fourth ventricle.

globose nucleus (nucleus globo´sus) a cerebellar nucleus lying between the emboliform nucleus and the nucleus fastigii and projecting its fibers via the superior cerebellar peduncle.

intracerebellar nuclei four accumulations of gray matter embedded in the white matter of the cerebellum, comprising the dentate nucleus, emboliform nucleus, nucleus fastigii, and globose nucleus.

lenticular nucleus (lentiform nucleus) the part of the corpus striatum somewhat resembling a biconvex lens, divided into a larger external or lateral part called the putamen and a smaller light colored internal or medial part called the globus pallidus.

motor nucleus any collection of cells in the central nervous system giving origin to a motor nerve.

olivary nucleus a folded band of gray matter that encloses a white core and produces the elevation called the olive on the medulla oblongata; it receives heavy projections from the spinal cord, mesencephalon, and cerebral cortex and projects fibers via the contralateral inferior cerebellar peduncle.

nuclei of origin, nu´clei ori´ginis groups of nerve cells in the central nervous system from which arise the motor, or efferent, fibers of the cranial nerves.

paraventricular nucleus (nucleus paraventricula´ris) a band of cells in the wall of the third ventricle in the supraoptic part of the hypothalamus; many of its cells are neurosecretory in function and project to the neurohypophysis, where they secrete oxytocin (and, to a lesser extent, antidiuretic hormone).

pontine nuclei, nu´clei pon´tis masses of nerve cells scattered throughout the ventral part of the pons, in which the longitudinal fibers of the pons terminate, and whose axons in turn cross to the opposite side and form the middle cerebellar peduncle, which projects fibers to the neocerebellum.

nucleus pro´prius a column of large neurons that extends throughout the posterior horn of the spinal cord.

nucleus pulpo´sus (pulpy nucleus) a semifluid mass of fine white elastic fibers forming the center of an intervertebral disk.

red nucleus (nucleus ru´ber) an oval mass of gray matter (pink in fresh specimens) in the anterior part of the tegmentum and extending into the posterior part of the hypothalamus; it receives fibers from the cerebellum.

sensory nucleus the nucleus of termination of the afferent (sensory) fibers of a peripheral nerve.

supraoptic nucleus (nucleus supraop´ticus) one just above the lateral part of the optic chiasm; many of its cells are neurosecretory in function and project to the neurohypophysis, where they secrete antidiuretic hormone (ADH) and, to a lesser extent, oxytocin; other cells are osmoreceptors that stimulate ADH release in response to increased osmotic pressure.

tegmental nucleus, laterodorsal several nuclear masses of the reticular formations of the pons and midbrain, especially of the latter, where they are in close approximation to the superior cerebellar peduncles.

thoracic nucleus (nucleus thora´cicus) thoracic column.

vestibular nuclei, nu´clei vestibula´res the four cellular masses in the floor of the fourth ventricle: superior (rostral or cranial), lateral, medial, and inferior (caudal) vestibular nuclei; in them are the terminations of the branches of the vestibular nerve (see anatomic Table of Nerves in the Appendices). The nuclei give rise to a widely dispersed special sensory system through projections to motor nuclei in the brain stem and cervical cord, to the cerebellum, and to motor cells throughout the spinal cord; they also have connections that provide for conscious perception of, and autonomic reactions to, labyrinthine stimulation.