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Encyclopedia > Nucleus raphe obscurus

The nucleus raphe obscurus, despite the implications of its name, has some very specific functions and connections of afferent and efferent nature. The raphe obscurus projects to the cerebellar lobes VI and VII and to crus II along with the nucleus raphe pontis (Brodal, A. Neurological Anatomy in relation to Clinical Medication 3rd ed. Oxford Press. 1981). This so called obscure nucleus has also been implicated in the modulation of the hypoglossal nerve. It has been observed that the ablation of this nucleus causes a change in the firing pattern in the XII nerve (Peever JH, Necakov A, Duffin J., "Nucleus raphe obscurus modulates hypoglossal output of neonatal rat in vitro transverse brain stem slices." Journal of Appl Physiol. 2001 Jan;90(1):269-79). In addition, the raphe obscurus mediates expiration via the inhibitory effect of serotonin and depresses periodic synaptic potentials (Lalley PM, Benacka R, Bischoff AM, Richter DW, "Nucleus raphe obscurus evokes 5-HT-1A receptor-mediated modulation of respiratory neurons". Brain Research Volume 747, Issue 1 , 30 January 1997, Pages 156-159). It has also been shown that this nucleus stimulates gastrointestinal motor function, microinjections of 5-HT into the n.r. obscurus increase gastric movement (Krowicki, ZK and Hornby, PJ. "Serotonin microinjected into the nucleus raphe obscurus increases intragastric pressure in the rat via a vagally mediated pathway", Pharmacology and Experimental Therapeutics. Volume 265, Issue 1, pp. 468-476, 04/01/1993). Figure 1a: A human brain, with the cerebellum in purple. ... The hypoglossal nerve is the twelfth cranial nerve. ... Expiration (2003) is an independent feature film directed by Gavin Heffernan In respiration, expiration is initiated by a decrease in volume and positive pressure exerted upon the intrapleural space upon diaphragm relaxation. ...

See also

The raphe nuclei (Latin for the bit in a fold or seam) is a moderately sized cluster of nuclei found in the brain stem, and releases serotonin to the rest of the brain. ...

External links

Rhombencephalon (hindbrain)

MYELENCEPHALON/MEDULLA: arcuate nucleus of medulla, solitary nucleus, hypoglossal nucleus, nucleus ambiguus, olivary body, cuneate nucleus, accessory cuneate nucleus, gracile nucleus, inferior salivatory nucleus, nucleus raphe obscurus, nucleus raphe magnus, nucleus raphe pallidus The University of Washington, founded in 1861, is a major public research university in Seattle, Washington. ... Wikipedia does not have an article with this exact name. ... The myelencephalon is a developmental categorization of a portion of the central nervous system. ... Position of medulla oblangata in the human brain The medulla oblongata is the lower portion of the brainstem. ... Grays Fig. ... The solitary nucleus and tract are structures in the brainstem that carry and receive visceral sensation and taste from the facial (VII), glossopharyngeal (IX), vagus (X) cranial nerves, as well as the cranial part of the accessory nerve (XI). ... The hypoglossal nerve is the twelfth cranial nerve. ... The nucleus ambiguus is a cranial nerve nucleus, located in the medulla oblongata, and handles the branchial motor functions of the ninth (glossopharyngeal) and tenth (vagus) cranial nerves. ... In anatomy, the olivary bodies or simply olives (Latin oliva) are a pair of prominent oval structures in the medulla oblongata, the lower portion of the brainstem. ... Cuneate nucleus is a wedge-shaped nucleus in the medulla. ... The accessory cuneate nucleus is located lateral to the cuneate nucleus in the medulla oblongata at the level of the sensory decussation (the crossing fibers of the posterior column/medial lemniscus tract). ... The swelling on the fasciculus gracilis is named the clava, and is produced by a subjacent nucleus of gray matter, the nucleus gracilis. ... The inferior salivatory nucleus is one of the components of the glossopharyngeal nerve, which stimulates secretion from the parotid gland. ... The nucleus raphe magnus, located directly rostral to the raphe obscurus, is afferently stimulated from axons in the spinal cord and cerebellum. ...

METENCEPHALON/CEREBELLUM: cerebellar vermis, flocculus, arbor vitae The metencephalon is a developmental categorization of portions of the central nervous system. ... Figure 1a: A human brain, with the cerebellum in purple. ... Part of the structure of animal brains, the cerebellar vermis is a narrow, wormlike structure between the hemispheres of the cerebellum. ... The flocculus is a small lobe of the cerebellum at the posterior border of the middle cerebellar peduncle anterior to the biventer lobule; it is associated with the nodulus of the vermis; together, these two structures compose the vestibular part of the cerebellum. ... The arbor vitae (Tree of Life) refers to the cerebellar white matter, so called for its branched, tree-like appearance. ...

METENCEPHALON/PONS: pontine tegmentum, trapezoid body, pontine nuclei (superior olivary nucleus, trigeminal nerve nuclei, abducens nucleus, facial nucleus, cochlear nuclei, vestibular nuclei), locus ceruleus, paramedian pontine reticular formation, nucleus centralis superior The metencephalon is a developmental categorization of portions of the central nervous system. ... Position of the pons in the human brain The pons (sometimes pons Varolii after Costanzo Varolio) is a knob on the brain stem. ... The pontine tegmentum is a part of the pons of the brain involved in the initiation of REM sleep. ... The trapezoid body is part of the acoustic pathway. ... The pontine nuclei are a part of the pons which store the memory of intention during motor activity. ... // Anatomy The superior olivary nucleus (or superior olive) is a small mass of gray substance situated on the dorsal surface of the lateral part of the trapezoid body. ... The abducens nucleus is the originating nucleus from which the abducens nerve emerges. ... The cranial nerve motor nucleus of the facial nerve is located in the lower pons. ... The cochlear nuclei consist of: (a) the lateral cochlear nucleus, corresponding to the tuberculum acusticum on the dorso-lateral surface of the inferior peduncle; and (b) the ventral or accessory cochlear nucleus, placed between the two divisions of the nerve, on the ventral aspect of the inferior peduncle. ... The Locus ceruleus, also spelled locus coeruleus, (Latin for the blue bit) is a nucleus in the brain stem (under the cerebellum in the caudal midbrain/rostral pons) apparently responsible for the physiological reactions involved in stress and panic. ... The paramedian pontine reticular formation, or PPRF, is a brain region, without clearly defined borders, in the center of the pons. ... The nucleus centralis superior is composed of polygonal, fusiform and pyriform neurons and exists rostral to the nucleus raphe pontis. ...

FOURTH VENTRICLE: obex, median aperture The fourth ventricle is one of the four connected fluid-filled cavities within the human brain. ... IrOBEX (or just OBEX) is a communications protocol that facilitates the exchange of binary objects between devices. ... The Median Aperture of the brain (apertura medialis ventriculi quarte) or Foramen of Magendie is an opening in the hollow nerve tube, connecting the 4th ventricle of the brain with the subarachnoid space The median aperture along with the paired lateral apertures (foramina of Luschka) are the primary routes for...



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