Unreferenced stub auto yes date December 2009 Infobox Brain Name Myelencephalon Latin GraySubject 187 GrayPage 767 Image EmbryonicBrain.svg Caption Diagram depicting the main subdivisions of the embryonic vertebrate brain. These regions will later differentiate into forebrain , midbrain and hindbrain structures. Image2 Caption2 IsPartOf Components Artery Vein BrainInfoType hier BrainInfoNumber 695 MeshName Myelencephalon MeshNumber A08.186.211.132.810.406 DorlandsPre m 24 DorlandsSuf 12553211 The myelencephalon is categorized as a secondary vesicle in the Morphogenesis development of the central nervous system . The prefix myelen is derived from Greek for medulla myelos . The myelencephalon differentiates primarily into the medulla oblongata and a caudal portion of the fourth ventricle , but will also contain portions of the following cranial nerves vestibulocochlear nerve CN VIII , glossopharyngeal nerve CN IX , vagus nerve CN X , accessory nerve CN XI , and hypoglossal nerve CN XII . The myelencephalon develops from the primary vesicular structure called the rhombencephalon or hindbrain , which is present in all vertebrate embryos. The rhombencephalon normally begins its differentiation into the myelencephalon and the metencephalon at approximately 5 weeks of gestational development in humans. Evolutionarily, the myelencephalon is the area of the brain which is the most ancestral, eventually controlling visceral mechanisms basic bodily functions such as breathing, heart and blood vessel activity, digestions, and peristalsis . Medulla and pons of rhombencephalon Fourth ventricle Category Developmental biology Neuroscience stub ca Mielenc fal nl Myelencephalon ... more details
Infobox embryology Name PAGENAME Latin flexura pontina GraySubject GrayPage Image Caption Image2 Caption2 MeshName MeshNumber Code Terminologia Embryologica TE E5.14.3.1.5.0.9 The pontine flexure is a bend in the axis of the embryological central nervous system the neuraxis . This flexure marks the junction between the metencephalon and the myelencephalon . The division of the rhombencephalon the early hindbrain into the metencephalon and the myelencephalon occurs at the 7th week of development. In the mature brain, the metencephalon forms the pons and cerebellum , whilst the myelencephalon forms the medulla oblongata . ref Neuroanatomy An Illustrated Color Text. 3rd Edition. Crossman & Neary. Published by Elsevier. ref Other Flexures The cephalic flexure also known as the midbrain flexure bends the neuraxis at the junction of the midbrain and hindbrain . This flexure develops by the 5th week of gestation . The cervical flexure bends the neuraxis between the brain and the spinal cord . It also develops by the 5th week of gestation . See also embryo ectoderm neural tube neurulation References reflist Development of nervous system Category Neuroanatomy Category Embryology of nervous system developmental biology stub neuroanatomy stub ... more details
Infobox Brain Name Rhombencephalon GraySubject 187 GrayPage 767 Image EmbryonicBrain.svg Caption Diagram depicting the main subdivisions of the embryonic vertebrate brain. These regions will later differentiate into forebrain , midbrain and hindbrain structures. Image2 Gray708.svg Caption2 Scheme of roof of fourth ventricle. IsPartOf Components Artery Vein BrainInfoType hier BrainInfoNumber 531 MeshName Rhombencephalon MeshNumber A08.186.211.132.810 NeuroLex Rhombencephalon NeuroLexID birnlex 942 DorlandsPre r 12 DorlandsSuf 12709581 The rhombencephalon or hindbrain is a Morphogenesis developmental categorization of portions of the central nervous system in vertebrates . File Rhombencephalon.jpg thumb right 300px Rhombencephalon The rhombencephalon can be subdivided in a variable number of transversal swellings called rhombomere s. In the human embryo eight rhombomeres can be distinguished, from caudal to rostral Rh7 Rh1 and the List of anatomical isthmi isthmus the most Anatomical terms of location rostral rhombomere . A rare disease of the rhombencephalon, rhombencephalosynapsis, is characterized by a missing vermis resulting in a fused cerebellum. Patients generally present with cerebellar ataxia . The caudal rhombencephalon has been generally considered as the initiation site for neural tube closure. ref http www.springerlink.com content f3fc056wde57c1yc SpringerLink Journal Article Bot generated title ref Myelencephalon Rhombomeres Rh7 Rh4 form the myelencephalon . The myelencephalon forms the medulla oblongata in the adult brain it contains a portion of the fourth ventricle , the glossopharyngeal nerve CN IX , vagus nerve CN X , accessory nerve CN XI , hypoglossal nerve CN XII , and a portion of the vestibulocochlear nerve CN VIII . Metencephalon Rhombomeres Rh3 Rh1 form the metencephalon . The metencephalon is composed of the pons and the cerebellum it contains a portion of the fourth ventricle, the trigeminal nerve CN V , abducens nerve CN VI , facial nerve ... more details
Unreferenced stub auto yes date December 2009 Infobox Brain Name Metencephalon Latin GraySubject 187 GrayPage 785 Image EmbryonicBrain.svg Caption Diagram depicting the main subdivisions of the embryonic vertebrate brain. These regions will later differentiate into forebrain , midbrain and hindbrain structures. Image2 Gray708.svg Caption2 Pons and cerebellum . IsPartOf Components Artery Vein BrainInfoType hier BrainInfoNumber 534 MeshName Metencephalon MeshNumber A08.186.211.132.810.428 NeuroLex Metencephalon NeuroLexID birnlex 965 DorlandsPre m 12 DorlandsSuf 12529123 The metencephalon is a Morphogenesis developmental categorization of portions of the central nervous system . The metencephalon is composed of the pons and the cerebellum contains a portion of the fourth ventricle and the trigeminal nerve CN V , abducens nerve CN VI , facial nerve CN VII , and a portion of the vestibulocochlear nerve CN VIII . Embryology The metencephalon develops from the higher rostral half of the embryon ic rhombencephalon , and is differentiated from the myelencephalon in the embryo by approximately 5 weeks of age. By the third month, the metencephalon differentiates into its two main structures, the pons and the cerebellum. Functions The pons regulates breathing through particular nuclei that regulate the breathing center of the medulla oblongata . The cerebellum works to coordinate muscle movements, maintain posture, and integrate sensory information from the inner ear and proprioceptors in the muscles and joints. See also List of regions in the human brain Pons Cerebellum Fourth ventricle Category Brainstem Category Central nervous system Category Cranial nerves Category Developmental biology Neuroscience stub az Arxa beyin ca Metenc fal cs Metencephalon de Metencephalon es Metenc falo Embriolog a fr M tenc phale it Metencefalo lt U pakalin s smegenys nl Metencephalon ... more details
File Hyakuninisshu 074.jpg thumb right Minamoto no Toyiyori as pictured in the Hyakunin Isshu Ogura Hyakunin Isshu . Japanese name Minamoto Nihongo Minamoto no Shunrai also Minamoto Toshiyori 1055 January 29, 1129 was an important and innovative Japanese poetry Japanese poet , who compiled the Gosen Wakash . He was the son of Minamoto no Tsunenobu 1016 1097 holder of the second rank in court and of the position of Grand Counsellor . Shunrai was favored by Emperor Go Sanjo and to a lesser degree Emperor Shirakawa in no small part for political reasons. At this time, the Fujiwara family dominated the country, and its branch, the Rokuj family , similarly dominated the court poetry scene by favoring their rivals, the Emperors could thus strike back. Although Shunrai was passed over to compile the Gosh i Wakash . Shunrai s angry polemical Nan Gosh i Errors in the Gosh ish appears to have somehow convinced Shirakawa to have Shunrai compile the next imperial anthology , the Kin y Wakash . This anthology , when completed, embroiled Shunrai in dispute, and his Gosen Wakash was especially criticized with various uncomplimentary nicknames Brower and Miner mention that one critic, Fujiwara no Akinaka floruit fl. 1100 1125 wrote a now lost ten part work called the Ry gyokush Collection of Genuine Jewels which did nothing but mock and criticize the Kin y Wakash . In 1113, Toshiyori wrote the poetic treatise known as Toshiyori zuin . Zuin , which is also seen in the title of Fujiwara no Kint s poetic treatise the Shinsen zuin , can be translated literally as myelencephalon , but this term was used to refer to books that contained essays on poetry and figuratively means that it knows the mind of poetry. References pgs. 237, 242 243 of Japanese Court Poetry , Earl Miner , Robert H. Brower . 1961, Stanford University Press, LCCN 61 10925 Persondata Metadata see Wikipedia Persondata . NAME Minamoto no, Shunrai ALTERNATIVE NAMES SHORT DESCRIPTION DATE OF BIRTH PLA ... more details
and myelencephalon . As the vertebrate grows, these vesicles differentiate further ... becomes, among other things, the pons and the cerebellum , the myelencephalon forms the medulla ... Myelencephalon Medulla oblongata colspan 5 align left Spinal cord Evolution Main Brain See also ... more details
Neuropsychology anatomy Anatomical regions of the brain are listed vertically, following hierarchies that are standard in neuroanatomy . Physiology Functional , nervous system vertebrate nervous systems connective , and Embryology developmental regions are listed horizontally in parentheses where appropriate. Rhombencephalon Hindbrain Rhombencephalon Myelencephalon medulla oblongata medullary pyramids Medullary cranial nerve nuclei Inferior salivatory nucleus Nucleus ambiguus Dorsal nucleus of vagus nerve Hypoglossal nucleus Solitary nucleus Metencephalon pons Respiratory centres pneumotactic centre apneustic centre Pontine cranial nerve nuclei chief or pontine nucleus of the trigeminal nerve sensory nucleus V motor nucleus for the trigeminal nerve V abducens nucleus VI facial nerve nucleus VII Vestibulocochlear nerve vestibulocochlear nuclei vestibular nuclei and cochlear nuclei VIII Superior salivatory nucleus paramedian pontine reticular formation cerebellum cerebellar vermis cerebellar hemispheres anterior lobe posterior lobe flocculonodular lobe cerebellar nuclei fastigial nucleus globose nucleus emboliform nucleus dentate nucleus Mesencephalon Midbrain mesencephalon tectum inferior colliculus inferior colliculi superior colliculus superior colliculi mesencephalic duct cerebral aqueduct, Aqueduct of Sylvius cerebral peduncle interpeduncular nucleus midbrain tegmentum ventral tegmental area Red Nucleus crus cerebri pretectum Prosencephalon Forebrain prosencephalon Diencephalon Epithalamus pineal gland pineal body habenular nuclei stria medullares tenia thalami Third ventricle Thalamus anterior nuclear group anteroventral nucleus anterodorsal nucleus anteromedial nucleus medial nuclear group medial dorsal nucleus midline nuclear group paratenial nucleus reuniens nucleus rhomboidal nucleus intralaminar nuclear group centromedial nucleus parafascicular nucleus paracentral nucleus central lateral nucleus central medial nucleus lateral nuclear group lateral dorsal nu ... more details
Infobox Brain Name Rostral Ventromedial Medulla Latin GraySubject GrayPage Image Gray700.png Caption RVM is labeled 5 in red at the bottom Image2 Caption2 IsPartOf Components Artery Vein BrainInfoType hier BrainInfoNumber 512 MeshName MeshNumber NeuroLex NeuroLexID DorlandsPre DorlandsSuf The rostral ventromedial medulla RVM , is a group of neurons located close to the midline on the floor of the medulla myelencephalon . The rostral ventromedial medulla sends descending inhibitory and excitatory fibers to the posterior horn of spinal cord dorsal horn spinal cord neurons . ref name Urban cite journal last Urban first M.O. title Supraspinal contributions to hyperalgesia journal PNAS year 1999 month July volume 96 issue 14 pages 7687 7692 doi 10.1073 pnas.96.14.7687 pmid 17831256 ref There are 3 categories of neurons in the RVM. On cells, off cells, and neutral cells. They are characterized by their response to nociceptive input. Off cells show a transitory decrease in firing rate right before a nociceptive reflex, and are theorized to be inhibitory. ref name Urban Activation of off cells, either by morphine or any other means, results in antinociception. ref name Morgan cite journal last Morgan first Michael title Periaqueductal Gray neurons project to spinally projecting GABAergic neurons in the rostral ventromedial medulla journal Pain year 2008 month November volume 140 issue 2 pages 376 386 doi 10.1016 j.pain.2008.09.009 pmid 18926635 ref On cells show a burst of activity immediately preceding nociceptive input, and are theorized to be contributing to the excitatory drive. Neutral cells show no response to nociceptive input. ref name Urban Involvement in Neuropathic pain Research has shown the RVM to be important in the maintenance of neuropathic pain. Ablation of mu Opioid receptor opioid expressing neurons in the RVM with a dermorphin saporin conjugate eliminated the allodynia and hyperalgesia caused by a nerve injury. Treatment with the dermorphin saporin con ... more details
pp move indef About the brains of all types of animals, including humans information specific to the human brain Human brain other uses Image Chimp Brain in a jar.jpg thumb alt A brain floating in a liquid filled glass jar. Yellowing of the handwritten labels on the jar give the object an antique appearance. A chimpanzee brain The brain is the center of the nervous system in all vertebrate and most invertebrate animals only a few primitive invertebrates such as sponge s, cnidaria jellyfish , sea squirts and echinoderm starfish es do not have one. It is located in the head, usually close to the primary sensory organs for such senses as vision, hearing, balance, taste, and smell. The brain of a vertebrate is the most complex organ in its body. In a typical human the cerebral cortex the largest part is estimated to contain 15 33 billion neuron s, ref Cite journal last Pelvig first DP last2 Pakkenberg first2 H last3 Stark first3 AK last4 Pakkenberg first4 B title Neocortical glial cell numbers in human brains journal Neurobiology of Aging year 2008 volume 29 pages 1754 1762 pmid 17544173 doi 10.1016 j.neurobiolaging.2007.04.013 issue 11 ref each connected by synapse s to several thousand other neurons. These neurons communicate with one another by means of long protoplasm ic fibers called axon s, which carry trains of signal pulses called action potential s to distant parts of the brain or body targeting specific recipient cells. From an evolutionary biological point of view, the function of the brain is to exert centralized control over the other organs of the body. The brain acts on the rest of the body either by generating patterns of muscle activity or by driving secretion of chemicals called hormone s. This centralized control allows rapid and coordinated responses to changes in the environment. Some basic types of responsiveness such as reflex es can be mediated by the spinal cord or peripheral ganglion ganglia , but sophisticated purposeful control of behavior ba ... more details
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