Sx006-神经总论脊髓.ppt

灰质连合 Gray commissure transverse bar of gray matter that connects horns across center of spinal cord. 中央管 Central canal, a longitudinal canal, traverses center of grey commissure. It continues superiorly with central canal of medulla oblongata. Grey matter of spinal cord contains an enormous number of neurons of varying size and shape. Main nuclei of spinal cord are as follows: ★ 1.后角 Posterior horn (column): 1)后角边缘核 Nucleus posteromarginalis forms a thin layer of cells covering tip of posterior horn. These cells are found throughout cord and their axons pass into lateral funiculus, probably forming intersegmental pathways. 2)胶状质 Substantia gelatinosa forms outer cap-like portion of head of posterior horn. They are presented at all spinal levels and may be excited by primary afferent fibers related to nociceptive stimuli. 3)后角固有核 Nucleus proprius is located deeply in substantia gelatinosa. Dendrites of cells radiate into substantia gelatinosa where they make synaptic contact with primary afferent fibers. Axons of nucleus cross in anterior white commissure and contribute to spinothalamic tracts. 4)胸核 Nucleus thoracicus is situated in medial portion of base of posterior horn. It begins to be well defined in C8~L3 segments and receives collateral branches of primary afferent fibers. Axons contribute fibers to posterior spinocerebellar tracts. ★ 2.中间带 Intermediate zone 1)中间内侧核 Intermediomedial nucleus receives collateral branches of posterior root fibers and gives rise to fibers that constitute spinocerebellar tract of both sides of spinal cord, regard sensation of viscera. 2)中间外侧核 Intermediaolateral n.(lateral horn) lies in segments T1~L3, containing sympathetic preganglionic neurons. 3)骶副交感核 Sacral parasympathetic nucleus lies in segments S2~S4, containing parasympathetic preganglionic neurons. ★ 3.前角Anterior horn (column) containing: 1)Three kinds of neuron ①α-motor neuron: larger multipolar neuron, innervates e