1、Nervous system 神經系統 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. 總論 Introduction to Nervous SystemCENTRAL NERVOUS SYSTEM 中樞神經系統 腦 brain 脊髓 spinal cordPERIPHERAL NERVOUS SYSTEM 周圍神經系統 腦神經 cranial nerves 脊神經 spinal nerves 內臟神經 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.內臟神經 autonomic nervous system分布于心肌、平滑肌和腺體，不受主觀意識控制，又稱自主神經或植物神經。又分為交感神經sympathetic nerve和付交感神經parasympathetic nerv

5、efundamental tissue of the nervous system: the nervous tissue is made up of two classes of cells, the neurons and neurologia.神經元 1.構造structure of neurons：胞體cell body軸突axon 樹突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尼氏體神經元纖維neurofibrilNissl bodyNeurofibrils樹突棘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)神經元分類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. 神經纖維nerve fibersIn the PNS both myelinated and unmyelinated fibers有髓和無髓纖維 have, in addition, an outer delicate nucleated membrane, the sheath of Schwann施萬細胞膜鞘 or nurolemmal sheath神經膜鞘. The peripheral myelinated fiber is structurally the most differentiate

10、d, consisting of axon, myelin and sheath of Schwann.A nerve fiber神經纖維 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神經纖維 in the CNS consists of the axon and the surrounding myelin sheath, or of the axon only in

11、 the case of unmyelinated fibers.突觸synapseA schematic nerve cell The axon terminals of the neuron are shown synapsing on the cell bodies of the postsynaptic neurons突觸后神經元. Structural features of a typical chemical synapse:presynaptic membrane突觸前膜, postsynaptic membrane突觸后膜, synaptic cleft突觸間隙, synap

12、tic vesicles突觸囊泡 Chemical synapses can be classified, according to the neuronal regions that participate in forming the synapse, into axodendritic軸-樹的 and axosomatic軸-體的 (most common), or dendrodendritic樹-樹的 and axoaxonal軸-軸的(less often).神經膠質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神經核 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灰質. (2)Cortex and medullary substance:The continuous sheet of grey matter covering the surface of the cerebrum and cerebellum is called the cortex皮質.The medullary substance, or medulla髓質 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纖維束. In the brain and spinal cord, concentrations of tracts constitute the white matter白質, 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神經節(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