1、Sui Hong-Jin,Chapter 5 The nervous Pathway,The nervous pathways are the routes formed by chains of neurons, through which sensory awareness reaches the cerebral cortex and a motor response is initiated.,For convenience of study, the nervous pathways are commonly classified into: sensory (ascending)
2、and motor (descending) ones.,Section 1 The sensory (ascending) pathway,In most sensory pathways there are three orders of neurons involved : the lowest sensory neurons, located in the peripheral ganglia, and their peripheral and central processes;,the intermediate neurons between the spinal ganglia
3、and thalamus; the highest sensory neurons, which are the cells of the thalamus and the fibers passing from them to the cerebral cortex.,The sensory pathways mainly include the deep and superficial sensory, visual and auditory pathways.,I The deep sensory pathway,1.The conscious deep sensory pathway,
4、 The conscious deep sensory and fine touch pathway of trunk and limb is sum up as follows:,Trunk limbs,muscles tendons joints periosteum,peripheral br,via. spinal n.,1 spinal ganglion,central br.,via. post. root,fasciculus cuneatus,fasciculus gracilis,T4,T5,2 Cuneate and gracile nuclei,med. arcuate
5、fibers med. lemniscus,3 VPL of thalamus,central thalamic radiation,via. post. limb of internal capsule,middle and sup. part of postcentral gyrus and posterior part of paracentral lobule and Precentral gyrus, The deep sensory pathway of head and face is still not known.,2. The unconscious deep sensor
6、y pathway,II The superficial sensory (the pain, temperature sensation and crude tactile) pathway,1. The superficial sensory pathway of trunk and limbs,skin of Trunk and limbs,peripheral br.,via. spinal n.,1 spinal ganglion,central br.,via. post. root,ascends 1-2 segments spinal cord,2 Nucleus propri
7、us,the fibers of pain and thermal sensation via. ant. white commissure forms lat. spinothalamic tract,the fibers of rough touch sensation do or not via. ant. white commissure forms ant. spinothalamic tract,3 VPL of thalamus,central thalamic radiation,via. post. limb of internal capsule,middle and su
8、p. part of post. central gyrus and post. part of paracentral lobule,2. The superficial sensory pathway of head and face,skin and mucous membrane,peripheral br.,via. br. of trigeminal n.,1 trigeminal ganglion,central br.,via. root of trigeminal n., trigeminal lemniscus,2spinal and pontine nuclei of t
9、rigeminal n.,3 VPMof thalamus,central thalamic radiation,via. post. limb of internal capsule,inf. part of postcentral gyrus of cerebral cortex,III The visual pathway,III The visual pathway,visual receptor rod cells cone cells,peripheral br.,1 bipolar cells,2ganglion cells,central br.,fibers from nas
10、al part of retina optic chiasma,fibers from temporal part of retina optic tract,via. post. limb of internal capsule,optic radiation,3 lat. geniculate body,the occipital cortex around calcarine sulcus,The papillary reflex pathway is sum up as follows: The light pupil retina optic nerve optic chiasma
11、optic tract pretectal area both accessory nucleus of oculomotor n. oculomotor n. papillary sphincterm.,IV The acoustic pathway,spiral organ,1 cochlear ganglion,peripheral br.,central br.,2 cochlear nucleus,parts of the fiberslat. lemniscus,parts of the fibers,3 med. geniculate body,acoustic radiation,via. post. limb of internal capsule,transverse temporal gyrus,
