神经解剖学课件：introduction to NS

1、Nervous SystemIntroduction and overviewIntroduction and overviewDivision of nervous system Organization of central nervous systemTerm of central nervous system(Development of CNS)Peripheral nervous system:31 pairs of spinal nerves 12 pairs of cranial nervesAutonomic nervous fibersgangliaThe human ne

2、rvous systemCentral nervous system :-Spinal cord & brainBrain stem medulla pons midbrainDiencephalonsCerebellumCerebral hemisphereThe human nervous systemThe brain occupied the cranial cavityThe spinal cord located in spinal canalThe cranial nerves attached to the brainThe spinal nerves attached to

3、spinal cordComponents and organisation of the nervous systemThe basic structural and functional unit of the nervous system is the nerve cell or neuron.NeuronBasic structure:BodyDendrites a axonAxons may be highly branched=collateralsTypes of neuronsby function: Afferent neuron/sensory neuron Efferen

4、t neuron/motor neuron Interneurons / relay neurons Types of neuronsby structure : multipolar neuron bipolar neuron unipolar neuron (pseudounipolar) Types of neuronsNumber, Length, and Mode of Branching of Neurites UnipolarSingle neurite divides a short distance from cell bodyPosterior root ganglionB

5、ipolarSingle neurite emerges from either end of cell bodyRetina, sensory cochlea, and vestibular gangliaMultipolarMany dendrites and one long axonFiber tracts of brain and spinal cord, peripheral nerves, and motor cells of spinal cordSize of NeuronGolgi type ISingle long axonFiber tracts of brain an

6、d spinal cord, peripheral nerves, and motor cells of spinal cordGolgi type IIShort axon that with dendrites resembles a starCerebral and cerebellar cortexThe nervous system is made up of millions, perhaps billions, of neurons.in the mature individual, do not undergo division and replicationInformati

7、on is passed between neurones at specialised regions called synapses. Synapse is the junction between two neurons where the electrical activity in one neuron influences the excitability of the second neuron. At this point (the synapse), Chemical and Electrical reaction occurs.Chemical synapsesPrinci

8、pal Neurotransmitters and Neuromodulators NeuromediatorsaFunctionReceptor MechanismIonic MechanismLocationPrincipal NeurotransmittersAcetylcholine (nicotinic), L-glutamateRapid excitationIon channel receptorsOpens cation channel (fast EPSP)Main sensory and motor systemsGABARapid inhibitionOpens anio

9、n channel for Cl- (fast IPSP)NeuromodulatorsAcetylcholine (muscarinic), serotonin, histamine, adenosineModulation and modification of activityG-proteincoupled receptorsOpens or closes K+ or Ca2+ channels (slow IPSP and slow EPSP)Systems that control homeostasisneurons neuroglia. astrocytes oligodend

10、rocytes microglia ependyma neuroglial cellsClinical significanceInjury of neuronInjury of axonAxonal transport and the spread of diseaseClinical notes of neurotransmittersInjury of neurogliaCerebral edemaTerms of NSGrey matter some regions in the CNS are relatively enriched in nerve cell bodies Whit

11、e matter some regions in CNS are relatively enriched in processes (usually axons) Ganglia some regions in the PNS are relatively enriched in nerve cell bodies Nerve cell bodies in the CNS with similar anatomical connection and function are called nucleiTerms of NSnerveNerve the processes (usually ax

12、ons) in the PNS often myelinated formed by nerve fibers of neurons: including the AXONS and their glial envelopes (myelin sheath)Terms of NSTracts that nerve processes sharing common connections and functions tend to follow same course are called running in pathways or tractAfferent tracts are calle

13、d ascending tract or affect (sensory ascending tract or pathway )Efferent tracts are called descending tract or effect (motor descending tract or pathway )Terms of NS -Decussationpathway conveying sensory(or motor) information to a conscious level (or motor area) crossover, or decussate the median p

14、lane , from one side to the other are called Decussation.In general, each cerebral hemisphere perceives sensations from, and controls the movements of , the contralateral side of the body. Decussation Decussate partlyoptic NChiasma Optic tractSummaryDefinitions of NS neuron (axon, dendrite, cell bod

15、y) grey matter, nuclei, ganglion white matter, tract , (pathway) decussation Overview of CNSBrain & Spinal Cordcallosum cerebellum MedullaPonsmidbrainhemispheres diencephalonthalamus hypothalamus Median sagittal section of brain showing the principal subdivision and some important landmarks in brain

16、Telencephalon Diencephalon Brain stemcerebellumVentricular systemVentricular systemVentricular systemspinal cord & spinal nerves 2 enlargements conus medullaris terminal filum cauda equinaSpinal cordSpinal cord: external featuresSpinal cord: external featuresNerves connected to spinal cord:Dorsal &

17、ventral rootsDorsal & ventral ramiStructures of spinal cordSulcus: ventral median fissure, dorsal medianGray matter: anterior horn, posterior horn, lateral horns, commissureCentral canal Spinal nerves Anterior root is motor Posterior root is sensory Anterior and posterior roots united to form spinal

18、 nerve at the IV foramen. Spinal nerve divides into anterior and posterior rami Relationship of Spinal Cord Segments to Vertebral NumbersVertebraeSpinal SegmentCervical vertebraeAdd 1Upper thoracic vertebraeAdd 2Lower thoracic vertebrae (79)Add 310th thoracic vertebraL1-2 cord segments11th thoracic

19、vertebraL3-4 cord segments12th thoracic vertebraL5 cord segment1st lumbar vertebraSacral and coccygeal cord segmentsDevelopment of CNSDevelopment of CNSA 45-year-old woman was examined by her physician and found to have carcinoma of the thyroid gland. Apart from the swelling in the neck, the patient

20、 also complained of back pain in the lower thoracic region, with a burning soreness酸痛radiating around the right side of her thorax over the 10th intercostal space. Although the back pain was often relieved by changing posture, it was worsened by coughing and sneezing. A lateral radiograph of the thoracic part of the vertebral column revealed a secondary carcinomatous deposit in the 10th thoracic vertebral body. Further physical examination revealed muscular weakness of both legs. Using your knowledge of neuroanatomy, explain the following: (a) the pain in the back, 脊髓后支感觉神