Physiological basics of food intake
There have been several questions recently regarding the regulation of food intake, so I invite you to read. It is written easily and briefly, even for people who have not previously dealt with physiology.
The famine center – located in the side of the hypothalamus, triggers the mechanism of searching, finding, acquiring and receiving food. (galanin-eat greasy, neuropeptide-y-carbohydrates).
Center of satiety – located in the nucleus of the hypothalamus; inhibits the appetite (leptin).
Information on the current state of the body and digestive tract is transmitted to these centers. Four types of motor, metabolic and thermal hormones serve this purpose, these signals stimulate one center and the other ones usually have a braking effect.
Motor signals – associated with enlargement and relaxation of the stomach. Stretching the walls of the stomach through the food gives a feeling of “fullness” and is a signal that inhibits consumption. However, stomach cramps after a certain time after eating a meal are a signal to eat a meal. Motor signals are picked up by the gastric wall mechanoreceptors and transmitted to the hypothalamus by the stomach nerves and vagus nerves.
Metabolic signals – related to concentration in the blood
-free fatty acids,
These signals are received directly by specialized hypothalamic neurons or sent to it on the nervous path from other parts, all of which have appropriate receptors.
The close relationship between the level of a given component in the blood and the sensation of hunger and satiety became the basis for, respectively
Meyer’s glucostatic theory.
Consumption of food causes the content of glucose in the blood to increase (hyperglycemia), which is accompanied by the appearance of satiety and a gradual loss of willingness to eat. However, the drop in blood sugar (hypoglycaemia) occurs several hours after a meal, which causes a feeling of hunger. Information about the blood glucose demand is received directly by the hypothalamus or via the liver.
For centers of hunger and satiety, it is not so much the absolute level of glucose in blood that is important, but the difference between its concentration in the portal vein and the arterial vein, and in the longer periods of glycogen reserve in the muscles and liver.
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