Satiety (
/səˈtaɪ.ə.ti/ ''sə-TYE-ə-tee'') is a state or condition of fullness gratified beyond the point of satisfaction, the opposite of
hunger
In politics, humanitarian aid, and the social sciences, hunger is defined as a condition in which a person does not have the physical or financial capability to eat sufficient food to meet basic nutritional needs for a sustained period. In t ...
. Following satiation (meal termination), satiety is a feeling of fullness lasting until the next meal. When food is present in the
GI tract after a meal, satiety signals overrule hunger signals, but satiety slowly fades as hunger increases.
The satiety center in animals is located in
ventromedial nucleus of the
hypothalamus
The hypothalamus (: hypothalami; ) is a small part of the vertebrate brain that contains a number of nucleus (neuroanatomy), nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrin ...
.
Mechanism
Satiety is signaled through the vagus nerve as well as circulating hormones. During intake of a meal, the stomach must stretch to accommodate this increased volume. This gastric accommodation activates stretch receptors in the proximal (upper) portion of the stomach. These receptors then signal through
afferent vagus nerve fibers to the hypothalamus, increasing satiety.
Signalling factors
In addition, as the food moves into the duodenum, duodenal cells release multiple substances that affect digestion and satiety.
Glucagon-like peptide-1 (GLP-1) is an
incretin
Incretins are a group of metabolic hormones that decrease Blood sugar level, blood glucose levels. Incretins are released after eating and augment the secretion of insulin released from Pancreas, pancreatic beta cells of the islets of Langerhans ...
released by the duodenum that inhibits relaxation of the stomach. This inhibition causes increased stretch of the stomach, increasing activation of proximal gastric stretch receptors. It also slows overall gut motility, increasing the duration of satiety.
This effect is used to increase weight loss and treat obesity through GLP-1 agonists.
(CCK) is gut peptide produced by the duodenum in response to fat and proteins. CCK has the effect of slowing gut motility and increasing satiety as well as activating release of pancreatic digestive enzymes and bile from the gallbladder.
See also
*
Ghrelin
*
Satiety value
*
Prader–Willi syndrome
Prader–Willi syndrome (PWS) is a rare genetic disorder caused by a loss of function of specific genes on chromosome 15. In newborns, symptoms include hypotonia, weak muscles, poor feeding, and slow development. Beginning in childhood, those ...
References
Digestive system
Neuropsychology
Nutritional physiology
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