Basjiruddin A Bagian Neurologi FK-Unand Anatomy Anatomically, the human nervous system is a complex of two division 1. CNS-The CNS, comprising the brain and spinal cord, is enclosed in bone and wrapped in protective covering (meninges) and fluid-filled space. 2. Peripheral Nervous System (PNS)-The PNS is formed by the cranial and spinal nerve (Fig 1.1) Neurons Neuronsvaryin size and complexity For example, the nuclei of one type of small cerebellar cortical cell (granule cell) are only slightly larger than the nucleoli of an adjacent large Purkinje cell Motor neuron are usually larger than sensory neurons The cell bodies is the metabolic and genetic center of a neuron (see fig 2-3) Dendrites Dendrites receive incoming synaptic information and thus, together with the cell body, provide the receptive pole of the neuron Most neuron have many dendrites (see fig.2-3) A single axon arises from the most neurons The axon is a cylindrical tube of cytoplasm covered by a membrane, the axolemma Synapses Communication between neurons usually occurs from the axon terminal of the transmitting neuron (presynaptic side) to the receptive region of the receiving neuron (postsinaptic side) Neuroglial cells outnumber neurons in the brain and spinal cord 1. Macroglia 2. Astrocytes 3. Oligodendrocytes 4. Microglia The central portion of the nervous system consist of the brain and theelongated spinal cord (fig 1-2) The brain has a tiered structure and form a gross point of view, can be subdivided into the cerebrum, the brain stem, and the cerebellum The cerebrum (forebrain) consist of the telenchepalon and the dienchepalon The telenchepalonincludes the cerebral cortex (the most highly envolved part of the brain, sometimes called gray matter) Sub cortical white matter, and the basal ganglia, which are gray masses deep within the cerebral hemispheres The white matter carries the name because, in a freshly sectioned brain, it has a glittening appearance as a result of its high lipid-rich myelin content The white matter consist of myelinated fibers and does not contain neuronal cell bodies or synapses The major sub division of the dienchepalon are the thalamus and hypothalamus The brain stem consist of the mid brain (mesenchepalon), pons, and medulla oblongata The cerebellum includes the vermis and two lateral lobes. The brain which is hollow, contains a system of spaces call ventricles Anatomi Hemisfer Serebrum Kedua hemisfer merupakan bagian terbesar otak Sulkus dan Fisura Utama Permukaan hemisfer serebrum mengandung banyak fisura dan sulkus yang memisahkan lobus frontalis, parietalis, oksipitalis, dan temporalis dari satu sama lain dan dari insula. Bagian-bagian otak yang terletak diantara sulkus dinamakan konvolusi atau girus Sulkus sentralis memisahkan lobus frontalis dari lobus parietalis Fisura kalkarina dimulai pada permukaan medial hemisfer dekat kutub oksipitalis dan membentang ke depan ke daerah sedikit di bawah splenium dari korpus kalosum Bagian dari korpus kalosum berbentuk busur;bagian anteriornya yang melengkung, genu berlanjut ke anteroventralis sebagai rostrum. Lobus frontalis Lobus frontalis membentang dari kutub frontal ke sulkus sentralis dan fisura lateralisLobus parietalis Lobus parietalis membentang dari sulkus sentralis ke fisuraparieto-oksipitalis, ke arah lateral, lobus ini meluas sampai ke fisura lateralis serebrumLobus Oksipitalis Lobus Oksipitalis yang berbentuk limasterletak di belakang fisura parieto-oksipitalis. Insula adalah bagian korteks serebrum yang tenggelam The Peripheral Nervous System (PNS) consist of spinal nerves, and their associated ganglia (group of nerve cells outside the CNS) The nerve contain nerve fibers that conduct information to (afferent) or from (efferent) the CNS THE SPINAL CORD AND THE ASCENDING AND DESCENDING TRACTS VERTEBRAL COLUMN The vertebral column is the central bony pillar of the body The vertebral column is composed of 33 vertebrae: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral (fused to form the sacrum), and 4 coccygeal (the lower 3 are commonly fused) Thespinalcordiscomposedofaninner core of gray matter, which is surrounded by anoutercoveringofwhitematter;thereis no indication that the cord is segmented. GRAY MATTER On cross section, the gray matter is seen as anH-shapedpillarwithanteriorand posterior gray columns, or horns united by a thingraycommissurecontainingthesmall central canal. WHITE MATTER Thewhitematter,forpurposesof description,maybedividedintoanterior, lateral,andposteriorwhitecolumnsor funiculi Theanteriorcolumnoneachsidelies betweenthemidlineandthepointofemergence of the anterior nerve root Thelateralcolumnliesbetweenthe emergenceoftheanteriornerverootsand the entry of the posterior nerve roots The posterior column lies between the entry of the posterior nerve roots and the midline Anatomi luar SumsumTulang Belakang Sumsumtulangbelakang(medulaspinalis, ataumielyn)merupakanmassajaringan syarafyangberbentuksilindermemanjangdan menempati dua pertiga bagian atas kanal spinalorangdewasadidalamkolumna vertebralis Masing-masingsegmendarisumsumtulang belakang mempunyai 4 akar Ke 31 saraf spinal yang muncul dari sumsum tulangbelakangmempunyaisatuakar ventralis dan satu akar dorsalis Akar ventralis Akarventralismempunyaiaksonneuron motorik Akar dorsalis Masing-masing akar dorsalis berisi serabut aferen dari sel-sel saraf dalam ganglionnya Dermatom Komponen sensorik dari masing-masing saraf spinaldidistribusikankesuatudermatom, yaitusuatubagiansegmendarikulitdengan batas yang jelas Polapersarafankulitbiasanyamengikuti distribusisegmentaldaripersarafanoto-otot yang pokok Zat Kelabu (Substansia Gricea) Kolumna : SuatuPotonganmelintangdari sumsumtulangbelakangyang memperlihatkanbagiandalam darimassazatkelabuyang berbentukhurufHyang dikelilingi oleh zat putihMengandung : Sistem serabut Ascenden Sistem serabut Descenden Theascendingtractsconductafferent information,whichmayormaynotreach consciousness. The information may be divided into two main groups : 1. Exteroceptiveinformation,which originates from outside the body, such as pain, temperature, and touch 2. Proprioceptiveinformation,which originatesfrominsidethebody,for example, from muscle and joints. Pain and Temperature Pathways Lateral Spinothalamic Tract The pain and thermal receptors in the skin and other tissues are free nerve endings Pain Reception Paincanbedividedintotwomaintypes:fastpain and slow pain Fastpainisexperiencedwhitinabout0,1second after the pain stimulus is applied Slowpainisfelt1,0secondorlaterafterthe stimulation Light (Crude) Touch and Pressure Pathways Anterior Spinothalamic Tract Theaxonsenterthespinalcordfromtheposterior rootganglionandproceedtothetipofthe posterior gray column. Themotorneuronssituatedintheanterior gray columns of the spinal cord send axons toinnervateskeletalmusclethroughthe anterior roots of the spinal nerves Thesupraspinalneuronsandtheirtracts aresometimesreferredtoastheupper motorneurons,andtheprovidenumerous separate pathways that can influence motor activity Thecorticospinaltractsarethepathwayscorcerned withvoluntary,discrete,skilledmovement, especially those of the distal parts of the limbs CORTICOSPINAL TRACTS Fibersofthecorticospinaltractariseasaxonsof pyramidalcellssituatedinthefifthlayerofthe cerebral cortex Thedescendingfibersconvergeinthecorona radiataandthenpassthroughtheposteriorlimbof the internal capsule Tractus corticobulbar (Nervus III) Menyilang sebelum inti Tractus corticobulbar Decussatio pyramidal Cortex CapsulaInterna Basis Pedunculi Nuc. N V Pons Cortico spinal lateral Medula Spinalis SISTEM PIRAMIDALIS Inthemedullaoblongata,thebundles becomegroupedtogetheralongtheanterior bordertoformaswellingknownasthe pyramid (alternative name pyramidal tract) At the junction of medulla oblongata and the spinalcord,mostofthefiberscrossthe midlineatthedecussationofthepyramids andenterthelateralwhitecolumnofthe spinalcordtoformthelateralcorticospinal tract Theremainingfibersdonotcrossinthe decussation but descend in the anterior white columnofthespinalcordastheanterior corticospinal tract ARTERIES OF THE BRAIN Thebrainissuppliedbythetwointernal carotidandthetwovertebralarteries.The arteries lie within the sub arachoid space, and theirbranchesanastomoseontheinferior surface of the brain to form the circle of Willis Internal Carotid Artery Theinternalcarotidarterybeginsatthe bifurcationofthecommoncarotidartery, whereitusuallypossessesalocalized dilatation, called the carotid sinus Branches of the Cerebral Portion 1. The ophthalmic artery 2. The posterior communicating artery 3. The choroidal artery 4. The anterior cerebral artery 5. The middle cerebral artery Vertebral artery The vertebral artery, a branch of the first part of thesubclavianartery,ascendtheneckby passingthroughtheforaminainthetransverse processes of the upper six cervical vertebrae Atthelowerborderofthepons,itjoinsthe vesseloftheoppositesidetoformthebasilar artery Circle of Willis ThecircleofWillisliesinthe interpeduncularfossaatthbaseofthe brain Itisformedbytheanastomoses betweenthetwointernalcarotid arteries and the two vertebral arteries VEINS OF THE BRAIN Theveinsofthebrainhavenomuscular tissue in their very thin walls, and the possess no valves External Cerebral Veins The superior cerebral veins pass upward over the lateral surface of the cerebral hemisphere Internal Cerebral Veins Therearetwointernalcerebralveins,and theyareformedbytheunionofthe thalamostriate vein and the choroid vein CEREBRAL CIRCULATION The blood flow to the brain must deliver oxygen, glucose, and other nutrients to the nervous tissue and remove carbon dioxide, lactic acid, and other metabolic by-product BLOOD SUPPLY OF THE SPINAL CORD Artery of the spinal cord : 1. Posterior spinal artery 2. Anterior spinal artery Theventriclesarefourfluid-filledcavities locatedwithinthebrain;thesearethetwo lateralventricles,thethirdventricle,andthe fourth ventricle Lateral Ventricle Third Ventricle Cerebral Aqueduct Fourth Ventricle Lateral Ventricles The lateral ventricles are the largest of the ventricles The anterior (frontal) horn is in front of the inter ventricular foramen The posterior (occipital) horn extends into the occipital lobe The inferior (temporal) horn transverses the temporal lobe, whose white substance forms its roof The two inter ventricular foramens, or foramens of Monroe, are apertures between the column of the fornix and the anterior end of the thalamusThird ventricle The third ventricle is a narrow ventricle cleft between the two halves of the diencephalon Fourth ventricle The fourth ventricle is a pyramid-shaped cavity bounded ventrally by the pons and medulla oblongata its floor is also known as the rhomboid fossa Chusid. 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