THE TITLE given to this paper is a bit inappropriate for a discussion in physiology, since the word "appetite" has a psychologic rather than physiologic meaning. Both hunger and appetite, as well as satiety, refer to sensations or affective states, and none of the three words has an accurate or precise definition. In the following discussion they are used only for convenience, and with only their common English meanings. They cannot be studied directly in human infants nor in laboratory animals, but only indirectly by simple observation as to whether food is or is not accepted, or by noting the amount of food eaten or the rate of eating. Perhaps a better title is "Mechanisms that regulate intake of food," using the word, "regulate," as it is used in the case of respiration. For example ventilation of the lungs is said to be regulated through the interaction of respiratory centers, reflexes, stretch receptors and chemoceptors. Analogous mechanisms doubtless serve to regulate feeding.
Like the regulation of respiration, the control of intake of food is one of the important functions of the central nervous system. The digestive apparatus is concerned only in a limited way and that as a system regulated, rather than as the regulator. Sherrington noted as early as 1900 that feeding persists after operations upon the stomach, including nearly complete removal of the organ. If such an operation leaves the tract adequate for digestion, it does not lead to any primary, quantitative disturbance of feeding behavior. Similar conclusions may be drawn from observations upon patients who have undergone the several types of operation upon nerves supplying the stomach and intestine, including patients subjected to vagotomy.
- Copyright © 1957 by the American Academy of Pediatrics