复旦大学：《系统解剖学 Systematic Anatomy》课程教学课件（讲稿）神经系统 Nervous System_5-12-nervous system- nervous pathway

Copy Right- Hongqi ZHANG-Department of Anatomy-Fudan University seD Systematic Anatomy Nervous system The conducting pathway Dr Hongqi zhang(张红旗) Email:Zhanghg58@126.com Copy Right- Hongqi ZHANG-Department of Anatomy-Fudan University

Copy Right- Hongqi ZHANG-Department of Anatomy-Fudan University Copy Right- Hongqi ZHANG-Department of Anatomy-Fudan University1 Dr.Hongqi Zhang (张红旗 ) Email: zhanghq58@126.com Systematic Anatomy Nervous system The conducting pathway

General introduction about the nervous pathways Concept Nervours pathway are the routes formed by chains of neurons, through which sensory awareness reaches the cerebral cortex and a motor response is initiated Category of nervous pathways The ascending(afferent or sensory) pathways The descending(efferent or motor) pathways Pyramidal system EXtrapyramidal system Each nervous pathway consists of a chain of tracts and associated nuclei Copy Right- Hongqi ZHANG-Department of Anatomy-Fudan University

Copy Right- Hongqi ZHANG-Department of Anatomy-Fudan University Copy Right- Hongqi ZHANG-Department of Anatomy-Fudan University Concept Nervours pathway are the routes formed by chains of neurons,through which sensory awareness reaches the cerebral cortex and a motor response is initiated. Category of nervous pathways: The ascending (afferent or sensory) pathways The descending (efferent or motor) pathways Pyramidal system Extrapyramidal system. Each nervous pathway consists of a chain of tracts and associated nuclei. General introduction about the nervous pathways

Copy riah Ascending(afferent or sensory) pathwar sity Different types of receptors receive different types of stimuli from the external and internal environment and generate corresponding nervous impulse which are conducted upward to the cerebral cortex centers to be processed to give rise to corresponding sensations Superficial sensation touch, pain, temperature& two point discrimination Deep sensations: proprioception, and vibration sense Visceral sensations: hunger. nausea and visceral pain Special sensations: smelling, sight, hearing. taste Copy Right- Hongqi ZHANG-Department of Anatomy-Fudan University

Copy Right- Hongqi ZHANG-Department of Anatomy-Fudan University Copy Right- Hongqi ZHANG-Department of Anatomy-Fudan University Ascending (afferent or sensory) pathway Different types of receptors receive different types of stimuli from the external and internal environment and generate corresponding nervous impulse.which are conducted upward to the cerebral cortex centers to be processed to give rise to corresponding sensations. Superficial sensation : touch,pain.temperature & two￾point discrimination. Deep sensations : proprioception,and vibration sense Visceral sensations: hunger.nausea and visceral pain. Special sensations: smelling,sight,hearing.taste

Generally, there are three grades neuron implicated In ascending pathway A chain of three long neurons and a number of interneurons conduct the nerve impulses generated in response to stimuli from an individual receptor to the somatosensory cortex First-order neuron: the cell bodies lie in a dorsal root ganglion or somatic afferent ganglia of cranial nn Second-order neurons: the cell bodies lie within the spinal cord or brain stem such as dorsal column nuclei(sensation of trunk limbs) or sensory nucleus of trigeminal nerve their axons usually decussate, ending in the thalamus Third-order neurons: the cell bodies lie in the thalamus project to the sensory cortex(center) Copy Right- Hongqi ZHANG-Department of Anatomy-Fudan University

Copy Right- Hongqi ZHANG-Department of Anatomy-Fudan University Copy Right- Hongqi ZHANG-Department of Anatomy-Fudan University A chain of three long neurons and a number of interneurons conduct the nerve impulses generated in response to stimuli from an individual receptor to the somatosensory cortex Generally,there are three grades neuron implicated In ascending pathway First-order neuron: the cell bodies lie in a dorsal root ganglion or somatic afferent ganglia of cranial nn. Second-order neurons: the cell bodies lie within the spinal cord or brain stem. such as dorsal column nuclei(sensation of trunk & limbs) or sensory nucleus of trigerminal nerve, their axons usually decussate, ending in the thalamus. Third-order neurons: the cell bodies lie in the thalamus. project to the sensory cortex (center)

Copy righ ANG-Department of Anatomv-Fudan University Sensory and motor pathways lists Trunk and limbs Proprioceptive(deep) sensations pathway Head and face Pathway of pain. T, touch pressure sensation(Sup. sensation) g0o3%茎 Visual pathway Trunk and limbs Pupillary light reflex Head and face Acoustic pathway Equilibratory pathway Visceral sensory pathway General visceral pathway Special visceral pathway Corticonuclear tract pyramidal system Cortospinal tract Cortico-neostriatum-dorsalthalamus-cortex circuit E Extrapyramidal system 1 Neastriatunmo-scubrstaetia nigrtexicrit Copy Right- Hongqi ZHANG-Department of Anatomy-Fudan University

Copy Right- Hongqi ZHANG-Department of Anatomy-Fudan University Copy Right- Hongqi ZHANG-Department of Anatomy-Fudan University Proprioceptive (deep) sensations pathway Pathway of pain.T,touch & pressure sensation (Sup. sensation) Visual pathway Pupillary light reflex Acoustic pathway Equilibratory pathway Visceral sensory pathway: Sensory pathwayGeneral visceral pathway Special visceral pathway Motor pathway Pyramidal system Extrapyramidal systemCortionuclear tract Cortospinal tract Cortico-neostriatum-dorsalthalamus –cortex circuit Neostriatum-substantia nigra circuit Corticoponto-cerebellar–cortex circuit Trunk and limbs Head and face Sensory and motor pathways lists Trunk and limbs Head and face

Central thalamic radiation VPL Conscious proprioceptive 3rd neuron bo and fine touch pathway of trunk and limbs Medial lemniscus Gracile and cuneate nuclei 2nd neuron body Decussation of medial lemniscus Fasciculus cuneatus T4 Spinal ganglion h- Fasciculus gracilis 1st neuron bod VPL-ventral posterolateral nucleus

Conscious proprioceptive and fine touch pathway of trunk and limbs Spinal ganglion 1st neuron body Fasciculus gracilis Fasciculus cuneatus Gracile and cuneate nuclei 2nd neuron body Decussation of medial lemniscus Medial lemniscus VPL 3rd neuron body Central thalamic radiation T4 VPL-ventral posterolateral nucleus

Fasciculus gracilis Fasciculus cuneatus Fasciculus cuneatus Fasciculus gracilis pinal ganglion

Fasciculus gracilis Fasciculus cuneatus Fasciculus gracilis Fasciculus cuneatus Spinal ganglion

Features of Conscious proprioceptive and fine touch pathway of trunk limbs Cell body position of 1st order neuron Spinal ganglion Cell body position of 2nd order neuron Gracile and cuneate nuclei in medulla oblongata Cell body position of 3rd order neuron Ventral posterolateral nucleus(VPL)in thalamus Position of decussation Upper portion of medulla ablongata Position of fiber tract in spinal cord Post funiculus of spinal cord Name of fiber tract in brain stem Medial lemniscus Position in internal capsule Posterior limb Projection area in cortex Upper 2/3 of postcentral gyrus and ant. part of paracentral lobula The feature (A)Fasciculus gracils- conduct sensory impulse above T 4; Fasciculus cuneatus--conduct sensory impulse below T 5 B)Fiber arrangement in post funiculus are fiber from sacral, lumbar, thoracic and cervical part from medial to lateral

Cell body position of 1st order neuron Spinal ganglion Cell body position of 2nd order neuron Gracile and cuneate nuclei in medulla ablongata Cell body position of 3rd order neuron Ventral posterolateral nucleus (VPL) in thalamus Position of decussation Upper portion of medulla ablongata Position of fiber tract in spinal cord Post.funiculus of spinal cord Name of fiber tract in brain stem Medial lemniscus Position in internal capsule Posterior limb Projection area in cortex Upper 2/3 of postcentral gyrus and ant.part of paracentral lobula The feature: (A)Fasciculus gracils – conduct sensory impulse above T 4;Fasciculus cuneatus-– conduct sensory impulse below T 5; (B)Fiber arrangement in post funiculus are fiber from sacral,lumbar,thoracic and cervical part from medial to lateral Features of Conscious proprioceptive and fine touch pathway of trunk & limbs

Central thalamic radiation Pain, temperature VPL and crude touch 3rd neuron body athway of trunk and limbs Spinal lemniscus Ant spinothalamic tract Lamina I ivvi d neuron bod Lat spinothalamic tract Spinal ganglia 1st neuron body VPL-ventral posterolateral nucleus

Spinal ganglia 1st neuron body LaminaⅠ,Ⅳ~Ⅶ 2nd neuron body Lat. spinothalamic tract Ant.spinothalamic tract Spinal lemniscus VPL 3rd neuron body Central thalamic radiation Pain, temperature and crude touch pathway of trunk and limbs VPL-ventral posterolateral nucleus

Spinothalamus tract Spinal ganglion

Spinothalamus tract Spinal ganglion