nerves.ppt - Cranial nerves & Cranial There are 12, paired...

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Cranial nerves & CranialCranial nerves & Cranialnerve nuclei :nerve nuclei :The base of the brainshowing locations ofcranial nervesThere are 12, pairedcranial nerves.The first 2 cranial Ns.attach directly to forebrain(frontal lobe) ,while therestattach to brain stem.Olfactory systemisattached to forebrain and isreferred to as the limbicsystem,/optic N.also isdiscribed in visual pathway.Cranial Ns. from3 - 12have nuclei (cranialN.nucluei)inthe brain stem, receivingafferents Fs.Orsendefferent Fs.as the cranialNs.
Superficial attachements ofSuperficial attachements ofCranialnerves :Cranialnerves :The base of the brainshowing locations ofcranial nervesOcculomotor &trochlear Ns.are attachedto midbrain.Trigeminal N.isattached to antero-lateralsurface of pons.Abducent, Facial &vestibulo-cochlear Ns.are lying between pons &M.O.from medial to lateral.Hypoglossal N.isattached to antero-lateralsulcusof M.O. / butglossopharyngeal, vagus& accessory Ns.are
Dorsal aspect ofbrain stemshowing locations ofAfferentcranial N. nuclei(left), andEfferentcranial N.nuclei(right), in which the samecolours have a commonAfferent NerveNuclei :Fibres carrying generalsensationfrom the headvia trigeminal N.terminate ina largetrigeminal sensorynucleusthat extends thewhole length ofbrain stemandcervical spinalcord.Fibres carrying hearing& motion/ positional sensevia vestibulo-cochlearN.terminate incochlear &vestibularnucleithat arelocated inupper M.O.Visceral afferentscarrying tastesensationviafacial &glossopharyngealNs.,
Efferent NerveNuclei :Somatic efferent column:supplies striated Ms. in head,including :yellow colour1- Oculomotornucleus.2-Trochlear nucleus.3-Abducent nucleus.4-Hypoglssal nucleus.Branchiomotor(specialvisceral) efferent column :supplies striated Ms. derivedfrombranchial arches,including :orange1- Trigeminalmotor nucleus.2- Facial motor nucleus.3- Nucleusambiguus.
SomaticefferentNerve NucleiOculomotor nucleus :lies at the base ofperiaqueductal grey ofmidbrain at the level ofsuperior colliculus.Itsefferent Fs. run inoculomotor N.to innervatelevator palpebraesuperiooris + all extraocularMs. ExceptL.R & S.OTrochlear nucleus :liesat theventral part ofperiaqueductal grey ofmidbrain at the level ofinferior colliculus.Itsefferent Fs. run in trochlear
Oculomotor & trochlearOculomotor & trochlearNervesNervesAnterior view of midbrainOculomotor nerve :emerges from the medialaspect of each cerebralpedunclee.g. through theinterpeduncular fossa.Trochlear nerve :emerges from back ofmidbrain,caudal to inferiorcolliculus and then passeslaterallyaround cerebralpeduncleto appear on theanterior view of midbrain.Posterior view ofmidbrain
Somaticefferent NerveNuclei :Abducent nucleus :liesin thecaudal pons ,beneath floor of 4thvent.

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