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1、Nervous Pathway,. The Sensory (Ascending) Pathways,) The deep sensory (or the proprioceptive) pathways,1.The conscious deep sensory pathways,1).The deep sensory and fine touch pathways of trunk and limbs,The first neurons: spinal ganglion,The second neurons: gracile and cuneate nuclei,The first neur
2、ons: ventroposterior lateral nucleus,Decussation of medial lemniscus,Lesion : hemiplegia,Receptors,muscles tendon periosteum and joint,Spinal nerve,(peripheral processes),Spinal ganglia,The first neurons,Dorsal roots (medial bundle),(Central processes : fasciculus cuneatus and gracilis),Gracile and
3、cuneate nuclei,The second neurons,thalamocortical tract,Running through the posterior limb of the internal capsule,Cortex of the cerebrum,Decussation of medial lemniscus,The third neurons,Ventroposterior lateral nucleus,Medial lemniscus, through the medulla oblongata pons and midbrain,2.The unconsci
4、ous deep sensory pathway,Receptors,muscles tendon periosteum and joint,Spinal nerve,(peripheral processes),Spinal ganglia,The first neurons,Dorsal roots,(Central processes),Thoracic nucleus of C8-C12 and lateral part of lamina- of lumbosacral enlargement,The second neurons,The anterior and posterior
5、 spinocerebellar tracts,By way of the superior and inferior cerebellar peduncles,Cortex of the cerebellum,) The superficial sensory pathways,1.The superficial sensory pathway of trunk and limbs,1).The pathway concerned with pain and thermal sensations,The first neurons: spinal ganglion,The second ne
6、urons: nucleus proprius,The first neurons: ventroposterior lateral nucleus,Cross through the anterior white commissure,Receptors,Cutaneous exteroceptor of the trunk and limbs,Spinal nerve,(peripheral processes),Spinal ganglia,The first neurons,Dorsal roots (lateral bundle),(Central processes : dorso
7、lateral fasciculus),Nucleus proprius,The second neurons,thalamocortical tract,Running through the posterior limb of the internal capsule,Cortex of the cerebrum,Cross through the anterior white commissure and form the lateral spinothalamic,The third neurons,Ventroposterior lateral nucleus,Run upward
8、within one or two segments,2).The rude tactile and pressure sensation pathway,The route is almost same as the pain and thermal pathway except for a little difference.,.The superficial sensory pathway of head and face,Receptor,skin,mucosa,Peripheral processes,Trigeminal ganglion,The first neurons,Cen
9、tral processes enter the pons,Spinal nucleus of trigeminal nerve(pain and thermal)、pontine nucleus of trigeminal nerve(tactile and pressure),The second neurons,trigeminal lemniscus,Ventroposterior medial nucleus,The third neurons,Thalamocortical tract,Posterior limb of the internal capsule,Inferior
10、part of the postcentral gyrus,) The visual pathways,1.Visual pathways,Receptor,Rod and cone cells,Bipolar cells,The first neurons,Ganglionic cells,The second neurons,Optic nerve, optic chiasma ,optic tract,Partial decussatuion of the fibers from the nasal halves of the retina,Lateral geniculate body
11、,The third neurons,Optic radiation,Posterior limb of the internal capsule,Both back of the calcarine sulcus,2. Pupillary reflexes(the direct pupillary light reflex and indirect pupillary light reflex),Retina,Optic nerve,Optic chiasma,Bilateral optic tract,Brachium of superior colliculus,Pretectal ar
12、ea,Accessory nucleus of oculomotor nerve,Oculomotor nerve,Cliary ganglion,Postganglionic fibers,Sphincter of the iris,) Acoustic pathway,Receptor,Corti organ,Cochlear ganglion,The first neuron,Cochlear nerve through the niternal acoustic meatus,Cochlear nuclei,The second neurons,Trapezoid body,Later
13、al lemniscus,Medial geniculate body,The third neurons,Acoustic radiation,Transverse temporal gyri,. The Motor (Descending) Pathways,The motor pathways include pyramidal and extrapyramidal systems.,Upper motor neurons,Lower motor neurons,) The pyrmidal system,1.The corticospinal tract:,arising from t
14、he giant pyramidal cells and certain other smaller cells of the superior and middle parts of the precentral gyrus and anterior part of the paracental lobule.,course the posterior limb of internal capsule,intermediate 3/5 of the crus cerebri,the basilar part of the pons.,form the pyramidal decussatio
15、n (70-90%) and continues as the lateral corticospinal tractin opposite side.,uncrossed fibers form the anterior corticospinal tract.,2.The corticonuclear tract:,arising from the inferior part of the precentral gyrus .,course through the genu of internal capsule and the brain stem.,gives rise to the collaterals to the bilateral oculomotor , trochlear , trigeminal motor , ambiguus , accessory nuclei and superior part of the facial nucleus , and to the contralateral hypoglossal nucleus and the inferior part of the facial nucleus.,Supranuclear paralysis (spastic paralysis or hard para