讲义说明学习nervous system

1、Nervous system 神经系统 The nervous system consists of the central nervous system (brain and spinal cord) and the peripheral nervous system (cranial and spinal nerves). The nervous system responds to the environment and internal conditions and stimulates the appropriate response. It also controls and co

2、ordinates the functions of the various systems. 总论 Introduction to Nervous SystemCENTRAL NERVOUS SYSTEM 中枢神经系统 脑 brain 脊髓 spinal cordPERIPHERAL NERVOUS SYSTEM 周围神经系统 脑神经 cranial nerves 脊神经 spinal nerves 内脏神经 autonomic nervous systemThe 31 pairs of spinal nerves emerge from the spinal cord. 8 pairs o

3、f cervical nerves, 12 pairs of thoracic nerves, 5 pairs of lumbar nerves, 5 pairs of sacral nerves and 1 pair of coccygeal nerves.The 12 pairs of cranial nerves (CN) arise from the brainCN I, olfactory nerve. CN II, optic nerve, CN III, oculomotor nerve; CN IV, trochlear nerve; CN V trigeminal nerve

4、: CN VI, abducent (abducens) nerve;CN VII,facial nerve; CN VIII. vestibulocochlear nerve: CN IX, glossopharyngeal nerve,CN X vagus nerve; CN XI,accessory nerve; CN XII, hypoglossal nerve.内脏神经 autonomic nervous system分布于心肌、平滑肌和腺体，不受主观意识控制，又称自主神经或植物神经。又分为交感神经sympathetic nerve和付交感神经parasympathetic nerv

5、efundamental tissue of the nervous system: the nervous tissue is made up of two classes of cells, the neurons and neurologia.神经元 1.构造structure of neurons：胞体cell body轴突axon 树突dendrites (Fig1: A large pyramidal neuron from the hippocamal cortex of the rat, showing the central soma and radiating branch

6、ed dendrites)Nissl bodies尼氏体神经元纤维neurofibrilNissl bodyNeurofibrils树突棘dendrite spine contacted by different types of synaptic terminalstypes of neurons(1)：morphologic types of neurons: classed by the configuration of their processes as unipolar, bipolar,or multipolar types of neurons(2)：morphologic t

7、ypes of neurons: classified by axon length as Golgi type I neurons with long axons, Golgi type II with short axons, and Amacrine neurons with no axonstypes of neurons(3)：functional types of neurons: classified by direction of nerve impulse flow as sensory(receptor) neurons, motor(effector) neurons,

8、and associationintern neurons(internneurons)神经元分类types of neurons(4)：chemical types of neurons: classified by the nature of released neurotransmitter as cholinergic, monoaminergic: catecholaminergic(adrenergic, noradre-nergic, dopaminergic; serotonergic) amino acids(excitatory: glutamic acid; inhibi

9、tory: gamma-aminobutyric acid) peptidergic3. 神经纤维nerve fibersIn the PNS both myelinated and unmyelinated fibers有髓和无髓纤维 have, in addition, an outer delicate nucleated membrane, the sheath of Schwann施万细胞膜鞘 or nurolemmal sheath神经膜鞘. The peripheral myelinated fiber is structurally the most differentiate

10、d, consisting of axon, myelin and sheath of Schwann.A nerve fiber神经纤维 in the CNS consists of the axon and the surrounding myelin sheath, or of the axon only in the case of unmyelinated fibers. A nerve fiber神经纤维 in the CNS consists of the axon and the surrounding myelin sheath, or of the axon only in

11、 the case of unmyelinated fibers.突触synapseA schematic nerve cell The axon terminals of the neuron are shown synapsing on the cell bodies of the postsynaptic neurons突触后神经元. Structural features of a typical chemical synapse:presynaptic membrane突触前膜, postsynaptic membrane突触后膜, synaptic cleft突触间隙, synap

12、tic vesicles突触囊泡 Chemical synapses can be classified, according to the neuronal regions that participate in forming the synapse, into axodendritic轴-树的 and axosomatic轴-体的 (most common), or dendrodendritic树-树的 and axoaxonal轴-轴的(less often).神经胶质glia( glial cells, or neuroglia)(1)Macroglia:AstrocyteEpen

13、dymal cellsOligodendrocyte(2)MicrogliaFundamental functioning manner of the nervous system: reflex,the structural basis of which is the reflex arc. peripheral receptor(2)afferent nerve or sensory neurons(3)central part or internuncial neurons(4)efferent nerve or motor neuron,(5)terminal effectorTerm

14、inology (1)Nucleus and grey matter: A nucleus神经核 is a fairly compact group of neuronal cell bodies and dendrites, of more or less similar form and function, located inside the CNS. The neuronal cell bodies and dendrites may form more extensive layers or masses in the CNS collectively called grey mat

15、ter灰质. (2)Cortex and medullary substance:The continuous sheet of grey matter covering the surface of the cerebrum and cerebellum is called the cortex皮质.The medullary substance, or medulla髓质 is a central core of white matter beneath the cortex of the cerebrum and cerebellum.(3)Tracts and white matter

16、: Bundles of nerve fibres in the CNS tend to be grouped separately to form tracts, or fasciculi纤维束. In the brain and spinal cord, concentrations of tracts constitute the white matter白质, so called because the axons are often ensheathed in myelin which glistens white in the fresh state. (4)Ganglion:In

17、 the PNS, the cell bodies and processes of neurons are grouped together as ganglia神经节(swellings). Sensory ganglion cells in dorsal roots of spinal nerves and some cranial nerves give off both centrally and peripherally directed processes, and do not have synapses on their cell bodies, whilst ganglionic neurons of the viscersl nervous system receive synaptic contacts from various sources. (5)Nerve: In the PNS, a nerve is a bundle of nerve fibers together with supporting connective tissue. Most of