The development of the human body; a manual of human embryology . :-,--^f- ft ^ • ^ Fig. 232.—Transverse Section through an Embryo Shark (Scyllium) OF 15 MM., SHOWING THE ORIGIN OF A SYMPATHETIC GANGLION. Ch, Notochord; E, ectoderm; G, posterior root ganglion; Gs, sympathetic ganglion; M, spinal cord.—(Onodi.) 442 THE SYMPATHETIC SYSTEM. 443 terminal link of a chain whose first link is a neuronebelonging to the central system (Huber). Throughoutthe thoracic and upper lumbar regions of the body thecentral system neurones form distinct cords known as thewhite rami communicantes (Fig. 233, WR), w
The development of the human body; a manual of human embryology . :-,--^f- ft ^ • ^ Fig. 232.—Transverse Section through an Embryo Shark (Scyllium) OF 15 MM., SHOWING THE ORIGIN OF A SYMPATHETIC GANGLION. Ch, Notochord; E, ectoderm; G, posterior root ganglion; Gs, sympathetic ganglion; M, spinal cord.—(Onodi.) 442 THE SYMPATHETIC SYSTEM. 443 terminal link of a chain whose first link is a neuronebelonging to the central system (Huber). Throughoutthe thoracic and upper lumbar regions of the body thecentral system neurones form distinct cords known as thewhite rami communicantes (Fig. 233, WR), which passfrom the spinal nerves to the adjacent ganglia of the gan-glionated cord, some of them terminating around the cellsof these ganglia, others passing on to the cells of the pre-vertebral ganglia, and others to those of the peripheral. Fig. 233.—Diagram showing the Arrangement of the Neuronesof the Sympathetic System. The fibers from the posterior root ganglia are represented by the brokenblack lines; those from the anterior horn cells by the solid black;the white rami by red; and the sympathetic neurones by , Dorsal ramus of spinal nerve; GC, ganglionated cord; GR, grayramus communicans; PG, peripheral ganglion; PVG, prevertebralganglion; VR, ventral ramus of spinal nerve; WR, white ramus com-municans.—(Adapted from Huber.) plexuses. In the cervical, lower lumbar and sacral regionswhite rami are wanting, the central neurones in the first-named region probably making their way to the sympa-thetic cells largely by way of the spinal accessory nerves,while in the lower regions they may pass down the gan-glionated cord from higher regions or may join the pre-vertebral and peripheral ganglia directly without passingthrough the proximal ganglia. In addition to these white 444 THE DEVELOPMENT OF THE HUMAN BODY.
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectembryol, bookyear1902
