The sympathetic nervous system in disease / by W. Langdon Brown.

  • Langdon-Brown, W. (Walter), 1870-1946.
Date:
1923
Catalogue details

Licence: In copyright

Credit: The sympathetic nervous system in disease / by W. Langdon Brown. Source: Wellcome Collection.

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    white and grey rami communicantes, and they send out branches that either run directly to the peripheral organs or to more outlying ganglia. These last branches often enter into large plexuses, such as the solar plexus. The vagus also enters into such plexus formation. These more outlying ganglia are termed collateral. There are also smaller groups of cells situated more peripherally along the course of the different nerve trunks before these enter the visceral organs, or even after they have so entered, such as the plexuses of Auerbach and Meissner in the intestines. These ganglia of the third order are called terminal ganglia. We must consider next, more precisely, how the sym¬ pathetic outflow reaches its destination (see fig. 5). The fine medullated pre-ganglionic connector fibre springs from a cell in the lateral horn : it passes out in the anterior root, which it leaves bv a white ramus com- 7 4J municans (■r.a.) to enter the sympathetic chain. It ends by forming synapses round cells in the lateral (G.vert.) collateral (G.sol.) or terminal (;p.G.) ganglia. In this way a single connector fibre may stimulate a number of cells. From these cells start the non-medullated post-ganglionic excitor fibres, which pass to their destination mainly along blood-vessels to the deeper parts and along spinal nerves to the more superficial parts, being distributed to the latter by the grey rami communicantes (r.g'.). This plan allows a wide radiation of sympathetic impulses, as was well shown by Langley in the case of the sym¬ pathetic fibres which erect hairs, the pilo-motor fibres. On stimulating a single grey ramus, the hairs will only erect over a single segmental area, but on stimulating a white ramus, erection occurs over a number of areas, usually five or six. The sympathetic ganglia, therefore, act as distributing-stations. Although every sympathetic impulse has one cell station outside the cord, no impulse passes through more than one such station : the excitor fibre runs straight to its destination. The term “ made