1、Dept. of Anatomy Zhou Hong YingInternal structures of brain stem grey matter white matter reticular formationReview the external structures of brain stem1. Important marksv Pyramids underlying pyramidal (corticospinal tract)v Decussation of pyramidsv Olive within inferior olivary nucleusv Gracile tu
2、bercle- fasciculus gracilis and nucleusv Cuneate tubercle fasciculus cuneatus and nucleus cuneatus v Convex of pon transverse pontine fiber - pontocerebellar fibers middle cerebellar peduncle v Facial colliculus abducens nucleus and fibers of facial nerve2. CN III XII attachment to brain stemDevelop
3、ment of spinal cord & brain stemDevelopment of spinal cordInternal structures in spinal cordAsecending tracts:Fasciculus gracilis & cuneatus Spinothalamic Descending tracts:Corticospinal tractIntersegmental tractv Fasciculus propriusCentral canalthree nulei column Anterior,posterior,and lateral or i
4、ntermediolateral horn Sulucus limitansSulucus limitans Central canal expend to form ventricle 7 Somatic sensorySomatic motorGeneral visceral motorGeneral visceral sensorySpecial visceral sensorySpecial somatic sensorySpecial visceral motorNuclei CN connected to cranial nervesGrey mattervNuclei CN co
5、nnected to cranial nervesv relay nuclei of ascending & descending tract ( NON cranial nuclei )- Nucleus of ascending and descending tract at different level of the brain stemWhite mattervascending & descending tractsvFibers take part in reflex Grey matter : Cranial nerve nucleisomatic motor nucleiv
6、Oculomotor nucleiv Trochlear nucleiv Abducens nucleiv Hypoglossal nuclei, , , cranial nerve nuclei near the median plane. Special visceral motor nucleiv Trigeminal motor nucleiv Facial nucleiv Accessory spinal nucleiv Ambiguus nucleiGeneral visceral motor nucleiv Accessory oculomotor nucleiv Superio
7、r & inferior salivatory nucleiv Dorsal motor vagus nucleisensory nuclei of CNGeneral & special visceral sensory nuclei -Solitary nucleussensory nuclei of CNGeneral somatic sensory nucleiv Trigeminal nuclei : Chief sensory v Mesencephlic v Spinal Vestibular nuclei from midpons to rostral medulla just
8、 lie beneath the vestibular area.Cochlear nuclei between the pons and medulla just lie beneath the lateral recess of rhomboid fossa.Special somatic sensory nucleirelay nuclei of ascending & descending tract ( NON cranial nuclei )Nucleus Gracilis & Nucleus CuneatusInferior olivary nucleusPontine nucl
9、eusSuperior & inferior collicus nucleiRed nucleus Substantia nigraWhite matterv ascending tract v descending tractMedial lemniscusconveys general somatic impulses of the proprioceptive which are mediated by receptors developed in the muscles, ligaments and joints1. Ascending tractsv conveys general
10、somatic impulses of exteroceptive (light touch, pain, pressure, heat, cold sense) from the opposite side of trunk and limbsSpinothalamic tractv conveys impulses of exteroceptive (light touch, pain, pressure,and heat,cold sense) from the opposite side of trigeminal nucleus that the peripheral process
11、 distribute to face and head, which are mediated by receptors developed in the skin.Trigeminothalamic tractv conveys the hearing (special somatic) from both sides of corti organ.Lateral lemniscusDescending tractsPyramidal system Corticospinal tract Corticonuclear tract Extrapyramidal systemCorticosp
12、inal tractv The largest number of fibers (nearly 90% )cross and descend in the posterior part of the lateral funiculus, as the lateral corticospinal tract.v uncrossed fibers into the anterior funiculus of spinal cord is called the anterior corticospinal tract.v conveys motor impulses from motor area
13、 of cortex to their termination motor nucleus of CN.Corticonuclear tractCorticonuclear tractv to 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 inter
14、connects the oculomotor, trochlear, abducens, Edinger-Westphal, vestibular, reticular and spinal accessory nuclei, coordinating conjugate eye movements and associated movements of the head and neck. reticular formationv consists of fibers and small groups of nucleusv the medulla and pons median zone
15、 containing nuclei rapheparamedian 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 pathwaysABCD Important transverse section
16、 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 the facial colliculus & abducens nucleus .5. Transverse section of the midbrain through the su
17、perior 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 ventricle Transverse section through the superior half of the medulla oblongata at the level of t
18、he 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 section of the midbrain at the level of th
19、e inferior colliculi Transverse section of the midbrain at the level of the superior colliculi. Transverse section of the ponsTransverse section of the pons through the facial colliculusTransverse section of the midbrain through the superior collicus Role of brain stemThe brain stem is the basic att
20、ention, inspiration, and consciousness of the brain. It sends all the information from the brain to the body. The brain stem controls breathing, heart rate, swallowing, control of sweating, blood pressure, digestion, temperature, alertness level, hormone balance, ability to sleep, and the reflexes of sight and hear of a persons body. The brain stem is in charge of all the functions that a human body needs to stay alive.
