Question

Cholecystokinin and duocrinin are secreted by.

Answer 1

Cholecystokinin is a gut hormone released after having a meal, which helps in digestion and reduces appetite. Duocrinin isa hormone which is found in the gastrointestinal tract it is liberated by the contact of gastric contents with the intestine and that stimulates the secretory activity of the duodenal glands (Brunner glands).

Complete answer:
Cholecystokinin is produced by I-cells present in the lining of the duodenum and is also released by some neurons in the brain; it acts on two types of receptors found throughout the gut and central nervous system.
The most important functions of this hormone are in digestion and appetite as it improves digestion by slowing down the emptying of food from the stomach and stimulating the production of bile in the liver. Bile acts like a detergent for the fat by making the fat droplets smaller so that enzymes can break it down more easily. Cholecystokinin also helps in increasing the release of fluid and enzymes from the pancreas to break down fats, proteins and carbohydrates.
Cholecystokinin is also involved with appetite by increasing the sensation of fullness in the short-term, that is, during a meal rather than between meals, it may do this by affecting appetite centres in the brain as well as delaying emptying of the stomach.
There has been some evidence which suggests that cholecystokinin may have a role in anxiety and panic disorders, because cholecystokinin released in the brain which causes this, it is not an effect of secretion from other parts of the body.
Fat and protein in the stomach causes the release of cholecystokinin in the duodenum and the release of cholecystokinin is blocked by the hormone somatostatin and by bile acids in the small intestine.
Duocrinin is secreted by duodenal mucosa, it stimulates the release of viscous mucus from Brunner's gland into the intestinal juice.

Note:
The innermost layer of the wall of the alimentary canal is called mucosa,certain cells of the mucosa of the stomach and intestine secrete important hormones,gastrointestinal mucosa is endometrial in origin. The intestinal mucosa secretes 6 hormones: Cholecystokinin, duocrinin, secretin, enterogastrone, enterocrinin, villikinin.