神经解剖学课件：Internal structures of brain stem

1、Internal structures of brain stem grey matter white matter reticular formationFunctions of brain stemconduit for the ascending tracts and descending tracts connecting the spinal cord to the different parts of the higher centers in the forebraincontains important reflex centers associated with the co

2、ntrol of respiration and the cardiovascular system and with the control of consciousnesscontains the important nuclei of cranial nerves III through XIIDevelopment of spinal cord & brain stemDevelopment of spinal cord & brain stemAsecending tracts:Fasciculus gracilis & cuneatus Spinothalamic Descendi

3、ng tracts:Corticospinal tractIntersegmental tractFasciculus propriusCentral canal three nulei column Anterior,posterior,and lateral or intermediolateral horn Motor Column1. GSE2. SVE3. GVESensory Column4. GVA5. SVA6. GSA7. SSASulucus limitansComponents of Cranial NervesSulucus limitansGeneral Viscer

4、al AfferentSpecial Visceral AfferentInternal structures in brain stem Central canal expend to form ventricle 7 nulei column:Somatic sensorySomatic motorGeneral visceral motorGeneral visceral sensorySpecial visceral sensorySpecial somatic sensorySpecial visceral motorNuclei CN connected to cranial ne

5、rvesGrey matterNuclei CN connected to cranial nerves relay nuclei of ascending & descending tract ( NON cranial nuclei )- Nucleus of ascending and descending tract at different level of the brain stemGrey matter : Cranial nerve nucleisomatic motor nucleiOculomotor nucleiTrochlear nucleiAbducens nucl

6、eiHypoglossal nuclei, , , cranial nerve nuclei near the median plane. Special visceral motor nucleiTrigeminal motor nucleiFacial nucleiAccessory spinal nucleiAmbiguus nucleiGeneral visceral motor nucleiAccessory oculomotor nucleiSuperior & inferior salivatory nucleiDorsal motor vagus nucleisensory n

7、uclei of CNGeneral & special visceral sensory nuclei -Solitary nucleussensory nuclei of CNGeneral somatic sensory nucleiTrigeminal nuclei : Chief sensory Mesencephlic Spinal Vestibular nuclei from midpons to rostral medulla just lie beneath the vestibular area.Cochlear nuclei between the pons and me

8、dulla just lie beneath the lateral recess of rhomboid fossa.Special somatic sensory nucleiCranial nerve nuclei and their CNCranial nerve nuclei and their CNrelay nuclei of ascending & descending tract ( NON cranial nuclei )Nucleus Gracilis & Nucleus CuneatusInferior olivary nucleusPontine nucleusSup

9、erior & inferior collicus nucleiRed nucleus Substantia nigraWhite matter ascending tract descending tractMedial lemniscusconveys general somatic impulses of the proprioceptive which are mediated by receptors developed in the muscles, ligaments and joints1. Ascending tracts conveys general somatic im

10、pulses of exteroceptive (light touch, pain, pressure, heat, cold sense) from the opposite side of trunk and limbsSpinothalamic tractconveys impulses of exteroceptive (light touch, pain, pressure,and heat,cold sense) from the opposite side of trigeminal nucleus that the peripheral process distribute

11、to face and head, which are mediated by receptors developed in the skin.Trigeminothalamic tractconveys the hearing (special somatic) from both sides of corti organ.Lateral lemniscusDescending tractsPyramidal system Corticospinal tract Corticonuclear tract Extrapyramidal systemCorticospinal tractThe

12、largest number of fibers (nearly 90% )cross and descend in the posterior part of the lateral funiculus, as the lateral corticospinal tract.uncrossed fibers into the anterior funiculus of spinal cord is called the anterior corticospinal tract. conveys motor impulses from motor area of cortex to their

13、 termination motor nucleus of CN.Corticonuclear tractCorticonuclear tractto their termination motor nucleus of CN and anterior horn of spinal cord much more than one time relay -synapses.Extrapyramidal systemMedial longitudinal fasciculus The medial longitudinal fasciculus interconnects the oculomot

14、or, trochlear, abducens, Edinger-Westphal, vestibular, reticular and spinal accessory nuclei, coordinating conjugate eye movements and associated movements of the head and neck. reticular formationconsists of fibers and small groups of nucleusthe medulla and pons median zone containing nuclei raphep

15、aramedian reticular nuclei. In the medulla it project mainly to the cerebellum.a medial zone regarded as an “effector”area,a smaller lateral zone referred to as the “sensory”part,because it receives collaterals from secondary sensory pathways A. Raphe Nuclei B. Central Nuclear GroupC. Lateral Nuclea

16、r GroupD. Precerebellar Reticular NucleiABCDReticular Formation Important transverse section of the brainstem1. Decussation of the corticospinal tracts 2. Decussation of the medial lemniscus3. Transverse section of the medulla through the mid-olivary level4. Transverse section of the pons through th

17、e facial colliculus & abducens nucleus .5. Transverse section of the midbrain through the superior collicus Transverse section at the level of the pyramidal decussation Transverse section at the level of the decussation of the medial lemniscus Transverse section at the caudal end of the fourth ventr

18、icle Transverse section through the superior half of the medulla oblongata at the level of the inferior olivary nucleus Transverse section through the pons at the level of the facial colliculus The central course of the fibres of the facial nerve in a transverse section Transverse section of the pons at the level of the trigeminal nerve Transverse secti