·308·PARTVINERVOUSSYSTEMfomthetrocharner,whh iatesthesupe1) Somatic motor nuclei The somatic motorrbiquandithqucrananmegngnuclei gives off somatic motor fibers to innervatefrom the dorsal surface of the brain stem.skeletal muscles derived from somites (includingc.Abducent nucleusIt lies deeply inthe facialglossal and extraocular muscles)and have 4pairs:colieulus andgives offfbersrunningventrllyanda, Oculomotor nucleus It is located at theemerging at medial part of bulbopontine sulcus tolevel of the superior colliculus and gives off fibersfomabducent nerve,whichinnervatesthlateralrtotake part in forming theoculomotor nerve,whichtus.innervates the superior, infrior,medial recti, inferiod.Hypoglossal nucleusIt is located deeply inobliquus and levator palpebrae superioris.the hypoglossal triangle and gives off fibers torunb.TrochlearnucleusItis situated atthelevelventrolaterally and emerge between the pyramid andof the inferior colliculus and sends fibersrunningtheolivetoformhypoglossalnerve,which innervatesdorsally to the rostral and of the superior medullaryall the muscles of the tongue on same side.velum, where they decussate to opposite side andemergefromthedorsal surfaceofthebrainstemtoorynucleusofoculomotorn.Red nucleusAccessNucleusofoculomotorn.OculomotornMesencephalic nucleus of trigeminal n.TrochlearrNucleus of trochlear nOphthalmic nPontinenucleusoftrigeminalnMaxillarynMandibulaMotor nucleus of trigeminal n.Nuclsofabducen.Abducent n.Nucleus of facial n.Facial n.Spinal nucleus of trigeminal n.Inferior olivary nucleuSuperior and inferiorsalivatory nucleiGlossopharyngeal n.NucleusambiguusVagus n重-Nucleus of hypoglossal n.Hypoglossal n.-Dorsal nucleus of vagus n.Cranialrootofaccessoryn-Nucleus of solitarytractCAccessorynucleu具O.Fig. V-2-18 The nuclei of cranial nerves in the brainstem (a stereogram)2) Special visceral motor nuclei The speciala. Motor nucleus of trigeminal nerve It lies invisceral motornucleigivesoff special visceral motorthe pons andgivesofffbers toform themotorrot offibers to innervate the skeletal muscles developedtrigeminal nerve. They travel in the trigeminal nervefrom branchial arche, including masticatory, facialand innervate mainly the masticatory muscles, tensorand pharyngolaryngeal muscles etc.tympani etc.扫描全能王创建
Chapter 2Central Nervous System · 309 .b.Nucleus offacialnerveItis situated at thethetic preganglionic fibers, the postganglionic fiberspontinreticularmatioThebersarisingminnervate smooth muscles and glands in the visceralthe facialnucleusfom thefacialnerve,andemergeiorgans of neck,thorax and the most visceral organsthebulbopontinesulcus lateraltotheabducentnerveof abdomen (the digestive canal before the left colicflexure and the parenchymatous organs),and the car-Theupperportionofthenucleusreceivesfbersfromthe corticonuclear tract of both sides and gives offdiac muscles of the heart.4) General and special visceral sensory nucleusnervefibers to innervate the facial muscles aboveThe general and special visceral sensory nucleus con-hpabassurewhileiswerorteivsists of just one nucleus, the nucleus of solitary tract.fibersonlyfrom theopposite corticonuclear tract andIt extends from the lower part ofthe pons to the levelgivesffnervefberstoinnervatesthefacialmusclesofmedial lemniscus decussation ofmedullaoblonga-below the palpebral fissure.ta, and receives primary visceral sensory fibers fromc. Nucleus ambiguousIt is placed in the retic-the facial, glossopharyngeal and vagus nerves. It isular formation of medulla oblongata and sends nervegenerally believed that the upper part of the nucleusfbers to take part in three cranial nerves: glossopha-is the gustatory nucleus, which receives the specialryngeal, vagus and accessory nerves, and to innervatevisceral sensory (gustatory)fibers.the skeletal muscles of pharynx, larynx, sot palate5) General somatic sensory nuclei General and upper part of esophagus.somatic sensory nuclei receive the primary somaticd. Accessory nucleusIt is located in the areasensory fibers from the skin of head and face, andlateral to the anterior horn of spinal grey matter frommucosa of oral and nasal cavities (Fig.VI-2-19)the level of pyramidal decussation to the fifth or sixthSpinal nucleus of trigeminal nerve is medial tocervical segment of spinal cord, and gives rise to fi-the spinal tract of trigeminal nerve, and receives thebers toform theaccessory nerve,and supplies stemo-primary somatic sensory fibers of trigeminal nervecleidomastoid muscle and trapizus.andgives off fibers to decussate to the opposite side3) General visceral motor nuclei General vis-and take part in forming thetrigeminal lemniscus.Itceral motor nuclei give off the general visceral motoris related to the conduction of pain and temperaturefibers (parasympathetic preganglionicfibers)and sup-sensations from the area of head and face where theply the smooth muscles and glands of the head, neck,trigeminal nerve distributes.thorax and most of abdomen, and the cardiac muscles.Pontine nucleus of trigeminal nerve is located ina. Accessory oculomotor nucleus It is alsothe pons,and receives theprimary somatic sensorycalled Edinger Westphal nucleus or E-W nucleus andfibers of trigeminal nerve that conduct the tactile andat the level of superior colliculus. The nucleus givespressure sensations of the skin, mucous membrane ofoff the parasympathetic preganglionic fibers, whichhead and face,cornea, conjunctiva and the meninges,travel in the oculomotor nerve and relay in the ciliaryand sends fibers to decussate to the opposite side andganglion. The postganglionic fibers innervate the cili-takepart in forming the trigeminal lemniscus.ary muscle and the sphincter pupillae.Mesencephalic nucleus of trigeminal nerve isb. Superior salivatory nucleusIt is located incomposed of pseudounipolar primary sensory neu-inferior part of the pons and sends parasympatheticrons. The peripheral processes of the neurons in thispreganglionic fbers, which run in the facial nerve andnucleus distribute to the masticatory muscles,fascialrelay in the pterygopalatine and submandibular gan-muscles and teeth etc.,their central processes termi-glia.The postganglionicfbers control the secretionofnatethepontine and spinal nuclei oftrigeminal nerve.the lacrimal, submandibular, sublingual glands, andThe mesencephalic nucleus of trigeminal nerve con-the mucous glands in the nasal and oral cavities.ducts the deep (proprioceptive) sensation of the headc. Inferior salivatory nucleusIt is situated inandface.the upper part ofthe medulla oblongata and sends6) Special somatic sensory nuclei The specialparasympathetic preganglionicfbers, whichtravelisomatic sensory nuclei receive the primary sensorythe glossopharyngeal nerve and relay inthe otic ganfibers of auditory and equilibrious sensations fromglonThepostganglioniberssupplythesecretioninternal ear, and include the cochlear nucleus and ves-of parotidgland.tibularnucleus.d. Dorsal nucleus of vagus nerve It lies undersIt is at the level of thea. Cochlear nucleusthvagaltriangleandgivesrsetohparasympa扫描全能王创建