Bodily changes in pain, hunger, fear, and rage : an account of recent researches into the function of emotional excitement / by Walter B. Cannon.

  • Cannon, Walter B. (Walter Bradford), 1871-1945.
Date:
1929
Catalogue details

Licence: In copyright

Credit: Bodily changes in pain, hunger, fear, and rage : an account of recent researches into the function of emotional excitement / by Walter B. Cannon. Source: Wellcome Collection.

    51/432 (page 29)
    THE CRANIAL DIVISION A CONSERVER OF BODILY RESOURCES The cranial autonomic, represented by the vagus nerves, is the part of the visceral nervous system con¬ cerned in the psychic secretion of the gastric juice. Pavlov has shown that when these nerves are severed psychic secretion is abolished. The cranial nerves to the salivary glands are similarly the agents for psychic secretion in these organs, and are known to cause also dilation of the arteries supplying the glands, so that during activity the giands receive a more abundant flow of blood. As previously stated (see p. 12), the evidence for a psychic tonus of the gastro-intestinal musculature rests on a failure of the normal contrac¬ tions if the vagi are severed before food is taken, in contrast to the continuance of the contractions if the nerves are severed just afterwards. The vagi artificially excited are well known as stimulators of increased tone in the smooth muscle of the alimentary canal. Aside from these positive effects on the muscles of the diges¬ tive tract and its accessory glands, cranial autonomic fibers cause contraction of the pupil of the eye, and slowing of the heart rate. A glance at these various functions of the cranial di¬ vision reveals at once that they serve for bodily con¬ servation. By narrowing the pupil of the eye they shield the retina from excessive light. By slowing the heart rate, they give the cardiac muscle longer periods for rest and recuperation. And by providing for the