Human physiology / by John Thornton.

  • Thornton, John
Date:
1899
Catalogue details

Licence: Public Domain Mark

Credit: Human physiology / by John Thornton. Source: Wellcome Collection.

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    whether nerve impulses are passing along nerve-fibres or not. It also shows that nerves conduct in both directions, though in one only is any effect manifest. Sending a co7istant electric current along nerve-fibres throws them into a state called ekctrotonus^ modifies the conductivity of the fibres, and increases the natural nerve current in the Fig. 55. —Transverse Section of the Spinal Cord of a Chick on the 9th day of incubation, prepared by Golgi's method. (Ramon y Cajal.) A, axis cylinders of anterior root-fibres issuing from large cells of the anterior horn, C. B, posterior root-fibres passing from the bipolar cells of the spinal ganglion into the posterior column of the spinal cord, Z>, where they bifurcate, d, and become longi- tudinal ; e^f^ collaterals from these fibres, passing into the grey matter. same direction. No chemical change has been detected in nerve-fibres as the result of nervous impulses passing, nor has any thermal change been observed in them, though the activity of nerve centres has been found to be accompanied by a development of heat. 51. Origins or Roots of Nerves.—A spinal nerve has its central extremity connected with the cord at a point termed
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