Kylläisyyssignaalit

Kylläisyyssignaalit, known in English as satiety signals, are physiological cues that inform the brain when an organism has consumed enough food. These signals originate from various parts of the body involved in digestion and nutrient absorption. They play a crucial role in regulating food intake and preventing overeating.

There are several types of satiety signals. Mechanical signals arise from the stretching of the stomach and intestines as they fill with food. These distension signals are transmitted to the brain via the vagus nerve. Hormonal signals are also important, released by the digestive tract in response to nutrients. Examples include cholecystokinin (CCK) released from the small intestine, which slows gastric emptying and promotes feelings of fullness, and peptide YY (PYY) which reduces appetite. Leptin, a hormone produced by adipose tissue, acts on the hypothalamus to signal long-term energy stores and influence satiety over longer periods.

Other signals include nutrient-related cues, such as the presence of glucose, amino acids, and fatty acids in the bloodstream, which are detected by receptors in the brain and liver. Temperature-related signals, like the warming of the stomach and intestines, can also contribute to satiety. The integration of these diverse signals in the brain, particularly in areas like the hypothalamus, ultimately leads to the conscious perception of fullness and cessation of eating. Disruptions in these signaling pathways can contribute to eating disorders and obesity.