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hunger |
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hunger [′həŋ·gər] (psychology) The need for food and the physiological and psychological mechanisms regulating food intake. Hunger A term most commonly used to refer to the subjective feelings that accompany the need for food; however, the study of this topic has come to include consideration of the overall control of food intake. More specifically, experimental work on the problem of hunger has been concerned with the sensory cues that give rise to feelings of hunger, the physiological mechanisms that determine when and how much food will be ingested, and the mechanism governing the selection of the food to be eaten. Food consumption is basically controlled by the organism's nutritional status. Food deprivation leads to eating, and the ingestion of food materials terminates hunger sensations. The issues are to determine which physiological processes vary quantitatively with nutritional status, and to find out if these changes can be detected by the nervous system in a manner that would instigate and terminate food consumption. Blood-sugar level, which has received more attention than any other factor, can be used as a case in point. The concentration of blood sugar does indeed vary appropriately in a general way with the periodicity of the food cycle. Detailed analyses of normal life variations of blood sugar, however, reveal that the relation between the concentration of blood sugar and hunger is not sufficiently close for this single humoral factor to be able to control hunger in any simple and direct manner. The evaluation of more local tissue utilization of food has proved a more promising approach to this problem. There is now some evidence suggesting that the status of the liver is pivotal in the control of feeding. Depletion of liver glycogen stimulates feeding; its repletion terminates feeding in rats and rabbits. See Carbohydrate metabolism, Liver Many stimuli that terminate feeding have been identified. Eating in food-deprived animals is inhibited by the reduction of either cellular water or of plasma fluid. It is also reduced by gastric distension and by infusing nutrients into the intestine and into the systemic, especially venous hepatic, circulation. Satiation produced by nutrient absorption from the intestine may be mediated, in part, by the gut hormone cholecystokinin. It is likely that cholecystokinin is effective because it reduces the rate at which food passes through the stomach. The previously held notions of discrete neural centers for the onset and termination of feeding have been abandoned, as the complexity of the feeding act and its corresponding neural complexity have become more widely appreciated. Deprivation of certain, specific food substances precipitates an increased appetite for the needed substance. This so-called specific hunger behavior has been demonstrated experimentally with many substances, such as salt, calcium, fats, proteins, and certain vitamins in children and in the lower animals studied. It is now clear that only the hunger for salt in salt-deprived animals appears before the animal has learned about the beneficial consequences of salt ingestion. Specific hungers for other minerals, proteins, and vitamins appear only gradually and reflect the animal's learning that certain foods are no longer beneficial and, in fact, may be harmful. See Thirst and sodium appetite Hunger Bangladesh suffered devastating famine in 1970s. [World Hist.: NCE, 224]
secessionist state of western Africa in which, during war with Nigeria, more than 1,000,000 people died of starvation (1968). [African Hist.: NCE, 290] condemned by Demeter to perpetual insatiety. [Gk. Myth.: Kravitz, 93] the beggar full of sores. [N.T.: Luke 16:19–31] estimated 200,000 Irish died (1846). [Irish Hist.: Brewer Note-Book, 705] punished with ceaseless hunger for food just beyond his reach. [Gk. Myth.: Hamilton, 346] asks workhouse-master for more gruel. [Br. Lit.: Oliver Twist] How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content. |
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