1、Nervous SystemDept. of Anatomy Zhou Hong Ying Introduction and overview Division of nervous system Organization of central nervous system Term of central nervous system (Development of CNS)Peripheral nervous system: 31 pairs of spinal nerves 12 pairs of cranial nerves Autonomic nervous fibers gangli
2、aThe human nervous systemCentral nervous system :-Spinal cord & brainlBrain stem medulla pons midbrainlDiencephalonslCerebellumlCerebral hemisphereThe brain occupied the cranial cavityThe spinal cord located in spinal canalThe cranial nerves attached to the brainThe spinal nerves attached to spinal
3、cordNeuronBasic structure:BodyDendrites a axonAxons may be highly branched=collaterals Efferent neuron/motor neuron Interneurons / relay neuronsby structure :l multipolar neuronl bipolar neuronl unipolar neuron (pseudounipolar)The nervous system is made up of millions, perhaps billions, of neurons.
4、Information is passed between neurones at specialised regions called synapses. Synapsen Synapse is the junction between two neurons where the electrical activity in one neuron influences the excitability of the second neuron. n At this point (the synapse), Chemical and Electrical reaction occurs.Che
5、mical synapses neurons neuroglia.Terms of NS Grey matter some regions in the CNS are relatively enriched in nerve cell bodies White 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
6、bodies in the CNS with similar anatomical connection and function are called nucleiTerms of NSnerve Nerve the processes (usually axons) in the PNS often myelinated formed by nerve fibers of neurons: including the AXONS and their glial envelopes (myelin sheath)Terms of NS Tracts that nerve processes
7、sharing common connections and functions tend to follow same course are called running in pathways or tract Afferent tracts are called 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
8、 -Decussation pathway conveying sensory(or motor) information to a conscious level (or motor area) crossover, or decussate the median plane , from one side to the other are called Decussation. In general, each cerebral hemisphere perceives sensations from, and controls the movements of , the contral
9、ateral side of the body. Decussation Decussate partlyoptic NChiasma Optic tractDefinitions of NS neuron (axon, dendrite, cell body) grey matter, nuclei, ganglion white matter, tract , (pathway) decussation Overview of CNSBrain & Spinal CordMedullaPonsmidbrainTelencephalon Diencephalon Brain stemcere
10、bellumspinal cord & spinal nerves 2 enlargements conus medullaris terminal filum cauda equinaSpinal cordTransverse sections of spinal cordSpinal cord: external featuresSpinal cord: external featuresNerves connected to spinal cord: Dorsal & ventral roots Dorsal & ventral ramiStructures of spinal cord Sulcus: ventral median fissure, dorsal median Gray matter: anterior horn, posterior horn, lateral horns, commissure Central canal Spinal nervesEach of the 31 pairs of spinal nerves is mixed nerve Somatic motorAutonomic motorDevelopment of CNS
