Sekretins

Sekretins are a group of hormones that play a crucial role in the regulation of digestion and nutrient absorption in the gastrointestinal tract. They are produced by the duodenum, a segment of the small intestine, in response to the presence of nutrients in the gut. The primary sekretins are secretin and cholecystokinin (CCK).

Secretin is primarily responsible for the stimulation of pancreatic enzyme secretion and the inhibition of gastric acid secretion. It acts on the pancreas to increase the release of bicarbonate, which neutralizes the acidic chyme entering the duodenum, and enzymes like amylase, lipase, and trypsinogen, which aid in the digestion of carbohydrates, fats, and proteins, respectively.

Cholecystokinin, on the other hand, stimulates the contraction of the gallbladder to release bile into the duodenum, facilitating the digestion and absorption of fats. It also inhibits gastric emptying and stimulates the release of insulin from the pancreas, promoting glucose uptake by cells.

Sekretins are released in response to the presence of specific nutrients in the duodenum. Secretin is released in response to the presence of acidic chyme, while CCK is released in response to the presence of fatty acids and amino acids. The release of sekretins is regulated by the vagus nerve and the enteric nervous system, which respond to the chemical composition of the chyme.

The secretion of sekretins is essential for maintaining proper digestion and nutrient absorption. Dysfunction of sekretin secretion can lead to digestive disorders such as pancreatitis, steatorrhea, and malabsorption. Sekretins are also involved in the regulation of other physiological processes, such as the control of blood glucose levels and the modulation of immune responses.