2 neuroanatomy

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  • Clinical NEUROANATOMYBasjiruddin ABagian Neurologi FK-Unand

  • General Plan Of The Nervous SystemAnatomyAnatomically, the human nervous system is a complex of two divisionCNS-The CNS, comprising the brain and spinal cord, is enclosed in bone and wrapped in protective covering (meninges) and fluid-filled space.Peripheral Nervous System (PNS)-The PNS is formed by the cranial and spinal nerve (Fig 1.1)

  • Cellular Aspect of neural DevelopmentNeuronsNeurons vary in size and complexityFor 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 cellMotor neuron are usually larger than sensory neurons

  • Cell BodiesThe cell bodies is the metabolic and genetic center of a neuron (see fig 2-3)

    DendritesDendrites receive incoming synaptic information and thus, together with the cell body, provide the receptive pole of the neuronMost neuron have many dendrites (see fig.2-3)

  • AxonsA single axon arises from the most neuronsThe axon is a cylindrical tube of cytoplasm covered by a membrane, the axolemmaSynapsesCommunication between neurons usually occurs from the axon terminal of the transmitting neuron (presynaptic side) to the receptive region of the receiving neuron (postsinaptic side)

  • NeurogliaNeuroglial cells outnumber neurons in the brain and spinal cord

    MacrogliaAstrocytesOligodendrocytesMicroglia

  • Structural Units & Overall organizationThe central portion of the nervous system consist of the brain and the elongated 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 cerebellumThe cerebrum (forebrain) consist of the telenchepalon and the dienchepalon

  • The telenchepalon includes 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 hemispheresThe 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 synapsesThe major sub division of the dienchepalon are the thalamus and hypothalamusThe brain stem consist of the mid brain (mesenchepalon), pons, and medulla oblongataThe cerebellum includes the vermis and two lateral lobes.The brain which is hollow, contains a system of spaces call ventricles

  • Hemisfer Serebrum/Telensefalon

    Anatomi Hemisfer SerebrumKedua hemisfer merupakan bagian terbesar otak Sulkus dan Fisura UtamaPermukaan 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 girusSulkus sentralis memisahkan lobus frontalis dari lobus parietalisFisura kalkarina dimulai pada permukaan medial hemisfer dekat kutub oksipitalis dan membentang ke depan ke daerah sedikit di bawah splenium dari korpus kalosumBagian dari korpus kalosum berbentuk busur;bagian anteriornya yang melengkung, genu berlanjut ke anteroventralis sebagai rostrum.

  • Lobus frontalisLobus frontalis membentang dari kutub frontal ke sulkus sentralis dan fisura lateralis

    Lobus parietalisLobus parietalis membentang dari sulkus sentralis ke fisura parieto-oksipitalis, ke arah lateral, lobus ini meluas sampai ke fisura lateralis serebrum

    Lobus OksipitalisLobus Oksipitalis yang berbentuk limas terletak di belakang fisura parieto-oksipitalis.Insula adalah bagian korteks serebrum yang tenggelam

  • Peripheral nervous systemThe 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 COLUMNThe 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)

  • STRUCTURE OF THE SPINAL CORDThe spinal cord is composed of an inner core of gray matter, which is surrounded by an outer covering of white matter; there is no indication that the cord is segmented.

    GRAY MATTEROn cross section, the gray matter is seen as an H-shaped pillar with anterior and posterior gray columns, or horns united by a thin gray commissure containing the small central canal.

  • WHITE MATTERThe white matter, for purposes of description, may be divided into anterior, lateral, and posterior white columns or funiculi The anterior column on each side lies between the midline and the point of emergence of the anterior nerve rootThe lateral column lies between the emergence of the anterior nerve roots and the entry of the posterior nerve rootsThe posterior column lies between the entry of the posterior nerve roots and the midline

  • Sumsum Tulang BelakangAnatomi luar Sumsum Tulang BelakangSumsum tulang belakang (medula spinalis, atau mielyn) merupakan massa jaringan syaraf yang berbentuk silinder memanjang dan menempati dua pertiga bagian atas kanal spinal orang dewasa di dalam kolumna vertebralis

  • Akar dan Saraf SpinalMasing-masing segmen dari sumsum tulang belakang mempunyai 4 akarKe 31 saraf spinal yang muncul dari sumsum tulang belakang mempunyai satu akar ventralis dan satu akar dorsalisAkar ventralisAkar ventralis mempunyai akson neuron motorik

  • Akar dorsalisMasing-masing akar dorsalis berisi serabut aferen dari sel-sel saraf dalam ganglionnyaDermatomKomponen sensorik dari masing-masing saraf spinal didistribusikan ke suatu dermatom, yaitu suatu bagian segmen dari kulit dengan batas yang jelas Pola persarafan kulit biasanya mengikuti distribusi segmental dari persarafan oto-otot yang pokok

  • Bagian Dalam Sumsum Tulang BelakangZat Kelabu (Substansia Gricea)Kolumna : Suatu Potongan melintang dari sumsum tulang belakang yang memperlihatkan bagian dalam dari massa zat kelabu yang berbentuk huruf H yang dikelilingi oleh zat putih

  • Jaras Zat Putih (Substansia Alba)Mengandung :Sistem serabut AscendenSistem serabut Descenden

  • THE ASCENDING TRACTS OF THE SPINAL CORDThe ascending tracts conduct afferent information, which may or may not reach consciousness. The information may be divided into two main groups :

    Exteroceptive information, which originates from outside the body, such as pain, temperature, and touch

    Proprioceptive information, which originates from inside the body, for example, from muscle and joints.

  • Pain and Temperature PathwaysLateral Spinothalamic TractThe pain and thermal receptors in the skin and other tissues are free nerve endingsPain ReceptionPain can be divided into two main types : fast pain and slow painFast pain is experienced whitin about 0,1 second after the pain stimulus is appliedSlow pain is felt 1,0 second or later after the stimulation

    Light (Crude) Touch and Pressure PathwaysAnterior Spinothalamic TractThe axons enter the spinal cord from the posterior root ganglion and proceed to the tip of the posterior gray column.

  • THE DESCENDING TRACTS OF THE SPINAL CORDThe motor neurons situated in the anterior gray columns of the spinal cord send axons to innervate skeletal muscle through the anterior roots of the spinal nerves

    The supraspinal neurons and their tracts are sometimes referred to as the upper motor neurons, and the provide numerous separate pathways that can influence motor activity

  • FUNCTIONS OF THE DESCENDING TRACTSThe corticospinal tracts are the pathways corcerned with voluntary, discrete, skilled movement, especially those of the distal parts of the limbs

    CORTICOSPINAL TRACTSFibers of the corticospinal tract arise as axons of pyramidal cells situated in the fifth layer of the cerebral cortexThe descending fibers converge in the corona radiata and then pass through the posterior limb of the internal capsule

  • Tractus corticobulbar (Nervus III)Menyilang sebelum inti

    Tractus corticobulbar

    Decussatio pyramidal

    Cortex

    Capsula Interna

    Basis Pedunculi

    Nuc. N V

    Pons

    Cortico spinal lateralMedula SpinalisSISTEM PIRAMIDALIS

  • In the medulla oblongata, the bundles become grouped together along the anterior border to form a swelling known as the pyramid (alternative name pyramidal tract)

    At the junction of medulla oblongata and the spinal cord, most of the fibers cross the midline at the decussation of the pyramids and enter the lateral white column of the spinal cord to form the lateral corticospinal tract

    The remaining fibers do not cross in the decussation but descend in the anterior white column of the spinal cord as the anterior corticospinal tract

  • BLOOD SUPPLY OF THE BRAINARTERIES OF THE BRAINThe brain is supplied by the two internal carotid and the two vertebral arteries. The arteries lie within the sub arachoid space, and their branches anastomose on the inferior surface of the brain to form the circle of Willis

    Internal Carotid ArteryThe internal carotid artery begins at the bifurcation of the common carotid artery, where it usually possesses a localized dilatation, called the carotid sinus

  • Branches of the Cerebral PortionThe ophthalmic arteryThe posterior communicating arteryThe choroidal arteryThe anterior cerebral arteryThe middle cerebral artery