《系统解剖学 Systematic Anatomy》课程教学资源（书籍教材）Cerebellum and Diacephalon.pdf_大学文库

Central Nervous System · 321 Chapter2roughthhamnueianfuentrIV . Blood Supply of thesavcerebri.Brainstem(5) Influence on the biological clocksBlood supply of the medullaThe reticular formationby means of is mulipleoblongataafferent andefferent pathways tothe hypothalamusprobably infuences the biologicalrhythmsThe vertebral, anterior and posterior spinal,pos-terior inferior cerebellar, and basilar arteries all send(6) Ascending reticular activating sys-branches to the medulla oblongata.temBlood supply of the ponsIt includes the sensory imput to the reticularfomation ofbrain stem,the projectionfrom thereThe pons is supplied by the basilar artery and theticularformation to diencephalons,and theextensiveanterior, inferior,and superior cerebellar arteriesprojection to cerebral cortex from the diencephalons.Almost allthe ascending specific sensory pathways3.Blood supply of the midbraingive off collateral branches in the brain stem intothe reticular formation, in which the specific sensoryThe midbrain is supplied by the posterior cerebralinformation is relayed in the “multi-synaptic" patternthe superior cerebellar, and the basilar arteries.by a series of the nuclei of the reticular formation.Then the information are farther relayed to the non-Luo Tao（罗涛）WangHuaqiao（汪华侨）specific nuclei of thalamus from the reticular forma-tion and become nonspecific.Finally the nonspecificinformation is extensively projected to the areas ofV.Cerebellumthe cerebral cortex.Multiple ascending pathways carrying sensoryThe cerebellum, literally means “little brain", isinformation to higher centers are channeled throughsituated in the posterior cranial fossa of the skull andthe reticular formation, which in turn projects thecovered superiorly by the tentorium of cerebellum.Itinformation to different parts of the cerebral cortex,lies posteriorto thefourthventricle,thepons and me-causing a sleeping person to waken, in fact it is nowdulla, anchored there by three pairs of fiber bundlesbelieved that the state of consciousness is dependentcalled cerebellar peduncles.Although the cerebellumon the continuous projection to the cortex of sensoryis mainly concerned with sensory information andinformation. Different degrees of wakefulness seemhas fewwaysto affectmotorneuronsdirectly,it isto depend on the degree of activity of the reticularconsidered part of the motor system because it coor-formation.dinates the voluntary movements.The lesion ofthe reticular formation of brain stemofen lead tothe disturbances ofconsciousness in dif.Gross appearance of the cere-ferent extent, which may range from feeting unconbellum (Fig.VI-2-28)sciousness to deep sustained coma.From the above description it must be apparentThe cerebellum consists of two cerebellar hemithat thenetworkofneurons inthe cerebrospinal axisspheres joined by a narrowmedian vermis.It has twoalmostoally ignoredinthe past,isnowbeing showsurface superior and inferior. The superior surfacetofuencepracticallyallactivitiesohebdy扫描全能王创建

Chapter 2 Central Nervous System · 323 .2)Theanterior lobe, which isseparatedfrompos1) The cerebellar cortex It consists of three lay-omsresoers molecular, piriform cell, and granular layers. Thethesuprorsufacehanteroboethmolecular layer lies immediately below the surface,withthyramdanduulaothinferormiscontains few cells and consists principally of unmy-nexprlluppaeivesselinated fibers. Among its cells are distinguished thenaliputsandsocaldsinocereellmorpalerouter stellate cells (lying ncar the surface) and theebellum.inner stellate or basket cells.The narrow piriform cell3)Theposteriorlobe, which isthe largestofthelayer consists of the larger ncrve cells ofthe cerebel-thmyrmlum, the Purkinjc cells. The next layer is the granular(onthe superferior surface)and bythe posterolcoterullayer. It is very rich in cells and consists of denselyfssure (on the inferior surface)packed small nerve cells, the granular cells, as well asThe posterior lobe (minus the pyramid and uvula)occasional larger cells,the Golgi cells.made up neocerebellum or cerebrocerebellum be-Different areas of the cerebellar cortex are prefer-cause it is thenewest part ofcerebellum to appear andentially related not only to particular inputs but alsoitreceives the corticocerebellar projections from theto particular cercbellar nucleus.The dentate nucleuscerebral cortex through the pontine nucleus.receives projcctions mainly fromthelateral partsofthe cerebellar hemispheres, the emboliform nucleus2.Internal structures of the cere-and globose nucleus from the paravermal cortex,andthe fastigial nucleus from the vermis.bellum2) The cerebellar nuclei (Fig. VI-2-29) Thereare four pairs of cerebellar nuclei in the medullaryThe cerebellum is composed of an outer coveringcenter of each side of the cerebellum. From lateral toof gray matter called the cerebellar cortex and innermedial these nucleus are the dentate, the emboliform,white matter called medullarycenter.Embeddedthe globose, and thefastigial nucleus.within the white matter are four pairs of nucleus.astigialnuclensCerebellarcortexGlobose nucleusDentatenuclerEmboliformnucleusMedullary centerFig. V-2-29 Internal structures of the cerebellumcortex is a mass of white matter, the medullary centerThe fastigial nucleus lies near the midline in theof the cerebellum. It is made up of three groups ofvermis and close to the roofofthe fourth ventricle.fibers:@intrinsic,@afferent,and③efferent.The emboliform nucleus is oval and situated me-The intrinsic fibers do not leave the cerebellumdial to the dentate nucleus.but connected different folia of the cerebellar cortexThe globose nucleus lies medial to the'emboli-and vermis on the same side,whileothers connecttheform nucleus.two cerebellar hemispheres together.The dentate nucleus, the largest ofthe cereblarThe afferent fibers form the great part of the whitenucleus,hastheshapeacrmpledbagwihmatter and proceed to the cerebellar cortex. Here, theyopeninfaingmedillyhinriortblose their myelin sheath and end as either climbing orllewiwhiemattemadrshatmossy fibers.The afferent fibers enter the cerebellumleavethenucleusfomargpartsupemainly through the inferior and middle cerebellar pe-cerebellar peduncle.duncles.3Thewhite matteroferebellumBeneaththe扫描全能王创建O

·324·PART VINERVOUSSYSTEMThe efferent fibers constitute the output ofthe cer-with increased muscle reflexes.3) The neocerebellum (cerehrocerehellum) re-ebellum and commence as the axons of the Purkinjeceives input from the cerebral cortex via a relay incells of the cerebellar cortex. The great majority ofpontine nucleus and sends fibers to the dentate nu-Purkinje cell axons passes to and synapses with thecleus. Axons of neurons in the dentate nucleus travelneurons of the cerebellar nuclei. The axons of thethrough the superior cerebellar peduncle and end byneurons then leave the cerebellum.synapsing with cells in the ventralintermediate nucleTheefferent and afferentfibers of cerebellum areus of the thalamus. The axons of the thalamic neuronsgrouped together on each side into three large pedun-terminate in the primary motor area of the cerebralcles, which connect the cerebellum to the midbrain,cortex. By this way, the neocerehellum can influencepons and medulla.The inferior cerebellar pedunclemotor neurons of the cerebral cortex, impulses from(or restiform body) is composed mainly of afferentsto cerebellum from the spinal cord and brainstem. Itthe motor cortex are transmitted to spinal segmentalarisesfromthe superiorhalf of the medulla oblon-levels through the corticospinal tract,and it representsgate.The two peduncles diverge as they ascend andthe apparatus for fine synchronization of voluntarypass into their respective cerebellar hemisphere.movement. Lesions of these region results in hypoto-The middle cerebellar peduncle (or arm of the nia, diminished or pendulum muscle jerks, intentionpons)is the largest of the three peduncles. It is com-tremor,clumsymovements and nystagmus.posed of afferents to cerebellum from the pontine nu-cleus of contralateral side.It arises from the pons andVI.Diencephalonenters cerebellar hemisphere on each side.The supe-rior cerebellar peduncle (or brachium conjunctivum)The diencephalon lies between midbrain and ce-contains the major efferent pathways from the cerebel-rebrum, almost entirely surrounded by cerebral hemi-lum to thered nucleus and thalamus.It runs superiorly,sphere, and therefore hidden from surface view.It islateral to the upperhalfof thefourthventricle,toentercavity forms the third ventricle. The diencephalon ac-the lower part of the midbrain on each side.counts for less than 2% of the weight of the brain, butit isextremely important.Eachhalf of the dienceph-3.Connections and functions of thealon is divided into dorsal and ventral part by hypo-cerebellumthalamic sulcus, extending from the interventricularforamen to the cerebral aqueduct. The diencephalon1) The archicerebellum (vestihulocerehellum)can be divided into five parts: the dorsal thalamus,mainly receives input from vestibular nucleus and②themetathalamus,③the epithalamus,the sub-primary fibers of vestibular nerve, and sends fibersthalamus, and the hypothalamus. (Fig VI-2-30).to the vestibular nucleus and other nucleus of themedulla oblongata. Axons of these neurons influence.Doral thalamus (Fig.VI-2-31)spinal segmental motor activity through the vestibulo-spinal tract and the medial longitudinal fasciculus. Itis involved in eyemovements and maintains balance.The dorsal thalamus is a larger, ovoid mass ofLesions of this part lead to disturbances with no alter-gray matter that forms the major part of the dien-ationof spinal reflexes.cephlon. There are two dorsal thalami and one is sit-2)The paleocereellum (spinocerehellum)receivesuated on each side of the third ventricle. The anteriorsomatic sensory information via spinocerebellar tractsend of the dorsal thalamus is narrow and roundedand sends fibers'to the fastigial nucleus and inter-called the anterior thalamic tubercle. The posteriorposed nucleus. The fibers end by synapsing with cellsend of the dorsal thalamus is expanded to from theof the vestibular nucleus, reticular formation of brainpulvinar. The surface of the dorsal thalamus formsstem and red nucleus, which give rise to axons of thepart of the lateral wall of the third ventricle and arevestibulospinal tract,reticulospinal tract and rubrospi-usually connected to the opposite dorsal thalamus bynal tract. The paleocereellum play an important rolea hand of gray matter, the interthalamic adhesion. Thein control of muscle tone and coordination of muscledorsal thalamus is covered on its lateral surface by amovement on the same side of the body. Lesions ofthin layer of white matter, called the external medulthis part cause disturbances of postural mechanismslarylamina.扫描全能王创建

326·PARTVINERVOUS SYSTEMolfactory information, and the relation of this infor.terolateral nucleus. Moreover, smaller nuclear groupsmation to one's emotional feelings and subjectiveare situated within the internal medullary lamina, andstates. They are concerned with emotional tone andsome are located on the medial and lateral surfaces ofthe mechanisms recent memory.thedorsal thalamus.Two types of thalamic nucleus may he distin-2.Metathalamusguished on the basis of their fibers connection:1)The"non-specific"nucleus which include themidline nucleus, the intralaminar nucleus and reticu-The metathalamus includes the medial and laterallar nucleus. They mainly receive afferent fibers fromgeniculate bodies, which are situated on each side ofthe rhinencephalon and reticular formation; they sendthe midbrain, below the thalamus.efferent fibers mainly to hypothalamus and corpus1) The medial geniculate body The medial ge-striatum. The nucleus are believed to influence theniculate body is an oval elevation situated just belowlevels ofconsciousnessandalertness inan individual.the pulvinar of the thalamas and later to the superior2)The nucleus which havefiber connections withcolliculus. It forms part of the auditory pathway. Thethe cerebral cortex are called specific thalamic nucle-afferent fibers to the medial geniculate body form theus, which further subdivided into special relay nucle-inferior brachium and come from the inferior collic-us and association nucleus. The special relay nucleusulus. The medial geniculate body receives auditorymediate finely-organized and precisely-transmittedinformation from both ears but predominantly fromsensoryinformation todiscrete cortical sensory area,the opposite ear. The afferent fibers leave the medialwhereas the association nucleus receive their princi-geniculate body to form the auditory radiation, whichpal non-cortical input from other thalamic nucleus.passes to the auditory cortex.The special relay nucleus include the ventral anterior2) The lateral geniculate body The lateral ge-nucleus,ventral intermediate nucleus and ventral pos-niculate body is a small oval swelling situated an-terior nucleus. The ventral anterior and ventral inter-terolateral to the medial geniculate body, below themediate nucleus have a major input from the dentatethalamus.It is connected to the superior colliculus bynucleus,globus pallidus and substantia nigra, its mainthe superior brachium, and forms part of the visualprojections pass to the motor and premotor regions ofpathway.It receives fibers concerned with visual in-the cerebral cortex. It probably influences the activi-formation from both eyes though information fromties of the motor cortex.both eyes through the optic radiation, which pass theThe ventral posterior nucleus is subdivided intoretrolentiform part of the internal capsule, to reach thethe ventral posteromedial nucleus and ventral pos-visual area of the cerebral cortex.terolateral nucleus.The ventral posteromedial nu-cleus revives the ascending trigeminal and gustatoryEpithalamuspathways, while the ventral posterolateral nucleusreceives the important ascending sensory tracts,themedial and spinal lemnisci.The thalamocortical pro-The epithalamus includes thalamic medullaryjections from these important nucleus pass throughstria, habenular trigone,habenular commissure,pinealthe posterior limb of the internal capsule and coronabody and posterior commissure. The pineal body liesradiate to the primary somatic sensory areas of theas a small, conical body on the posterior wall of thecerebral cortex in thepostcentral gyrus.third ventricle, above the superior colliculus. It is anThe association nucleus include the anterior nu-endocrine gland. In adults, the pineal body containsclear group, medial nuclear group and the dorsal tierlarger foci of calcification, which are visible on ra-of lateral nucleargroup.They have interconnectionsdiographs. The habenular trigone contains habenularwith other thalamic nucleus and with the cingulatednucleus. Afferent tracts reach the habenular nucleusgyros,frontal,parietal,occipital and temporal lobesthrough the medullary stria. This contains fibers fromof cerebral hemisphere. They also have similar con-the nucleus of the septum, the anterior perforatednection with the hypothalamic nucleus. They aresubstance and the preoptic region.The efferent tractsresponsible for the integration of a large variety ofextend into the midbrain (Fig.VI-2-30).sensoryinformation,including somatic,visceral,and扫描全能王创建

Chapter 2 Central Nervous System · 327 diencephalons and tegmentum of midbrain, contain Subthalamussubthalamic nucleus, parts of red nucleus and sub-stantia nigra (Fig. V-2-32).ThesubhalamusiatransitionzonebetwenCerebral longitudinal fissureCorpus callosumCaudate nucleusIntermal capsuleAnterior nucleusofthalamusClaustrumMedial nuclei of thalamusInsular lobePutamenExternalcapsuleLateral nucleai ofthalamusGlobusPallidusRed nucleusSubthalamic nucleusSubstantia nigraCerebellumPonsInferior olivary nucleusMedulla oblongataFig. VI-2-32The coronal section of diencephalonparasagittal plane into medial and lateral zones. Lyingwithin the plane are the columns of the fornix and5.Hypothalamusthe mammilothalamic tract, which serve as markers(Fig. VI-2-33).Thepreopticregion extendfromtheanteriorcom-The hypothalamus lies below the dorsal thalamusmissure to the chiasma and contains preoptic nucleus.and forms the floor and inferior part of the lateralThe supraoptic region lies above the optic chiasma,wlls of the third ventricle. It extends forward fromcontains the supraoptic nucleus and the paraventricu-the optic chiasma to the lamina terminalis and thelar nucleus.The hormones vasopressin and oxytocinanterior commissure. Caudally, the hypothalamusare synthesized in the nerve cells of the supraopticmerges into the tegmentum of the midbrain. Whenand paraventricular nucleus. The hormones are passedobserved from below,the hypothalamus is seen toalong the axons together with carrier proteins calledwema'neurophysins and released at the axon terminals. Hereto posterior:theoptic chiasma, thetuber cinereumthe hormones are absorbed into bloodstream in thewhihbcmesfuelshapedfmthifundibcapillaries of the posterior lobe of the hypophysis.lum and the mamillary bodies.The hormone vasopressin is produced mainly in theThe hypothalamus is composed of smal nervesupraoptic nucleus. Its function is to cause vasocon-estustriction. It also has an important antidiuretic func-Whharenolearysatdfomoanothrtion, causing an increased absorption of water in thedistal convoluted tubules and collecting tubules of thekidney. The hormone oxytocin is mainly produced ineiovm扫描全能王创建O

·328·PARTVINERVOUSSYSTEMing hormones and release-inhibitory hormones. Thethe paraventricular nucleus. Oxytocin stimulates thehormones are packaged into granules and transportedcontraction of the smooth muscle of the uterus andalong theaxonsof these clsintothemedianemicauses contraction of the myoepithelial cells that sur-nence and infundibulum. Here, the granules are re.round the alveoli and ducts of the breasts. The princi-leased by exocytosis ontofenestrated at the upperendpal nucleus of the tuberal region are the infundibularofthhyophysealporral sytemThortalsystemnucleus, ventromedial nucleus and dorsomedial nu-carries thereleasing homonesand releaseinhibitorycleus. The mamillary region contains mamillary andhormones to the secretory cells of the anterior lobe ofposterior hypothalamic nuclei. Neurosecretory cellsthe hypophysis.situated mainly in the medial zone of the hypothala-mus are responsiblefor the production of the releas-FormixAnteriorcommissurePosterior hypothalamic nucleusParaventricular nucleusDorsomedial nucleusAnterior hypothalamic nucleusVentromedial nucleusPreoptic nucleusNucleiofmammillarybodySupraoptic nucleusInfundibulumPituitary gland(Hypophysis)Fig.VI-2-33 The representation of hypothalamic nucleiThe hypothalamus receives many afferent fiberscrine glands.The hypothalamus influence all processes import-fromtheviscera,theolfactorymucous membrane,thecerebral cortex,and the limbic system.The efferentant for the maintenance of homeostasis and regulateconnections of the hypothalamus also are numerousthe functions of the organs responding to momentaryand complex.Many nucleus have long axons thatbodily stress: warmth, water and electrolyte balance,pass through the brain stem and spinal cord to pre-cardiac function, circulation and respiration,metab-ganglionic sympathetic cells on the lateral horn of theolism and the sleeping and waking rhythm are underthoracicandupperlumberparts,nglionictheircontrol.Vitalfunctions, such as eating,gastroinandtoparasympathetic cells in the lateral horn of the sacraltestinal activity and defecation, fluid intake and mic-segments,of the spinal cord.Thehypothalamusturition are regulated from this region, just as are pro-is connected to the hypophysisbytwopathways:creation and sexuality. Vital functions are initiated by@ nerve fibers that travel from the stsupraopticandbodily needs, which are perceived ashunger,thirst,orparaventricular nucleus to the posterior lob of the hy-sexual drive. The instinctive actions which allow thepophysis,and②longand shortportalbloodvesselsorganism to survive and which are usually accompa-that connect sinusoids in the median eminence andnied by a marked affective component are pleasure ofinfundibulum with capillary plexuses in the anteriordispleasure, happiness, fear or anger. Hypothalamuslobe of the hypophysis.These pathways enable theexcitation is of great importance in the arousal ofhypothalamus to influence the activities of the endo-such emotions.扫描全能王创建