Tag: gastrointestinal tract and liver

• Cholecystokinin is a peptide hormone of the gastrointestinal system responsible for stimulating the digestion of fat and protein. 
• Cholecystokinin, officially called pancreozymin, is synthesized and secreted by enteroendocrine cells in the duodenum, the first segment of the small intestine. 
• Cholecystokinin also increases the release of fluid and enzymes from the pancreas to break down fats, proteins and carbohydrates.
•  Cholecystokinin seems to be involved with appetite by increasing the sensation of fullness in the short-term, that is, during a meal rather than between mealsHence, Cholecystokinin involves in Controlling appetite.
So, the correct answer is 'Controlling appetite'.

• Cholecystokinin, officially called pancreozymin, is synthesized and secreted by enteroendocrine cells or I-cell in the duodenum, the first segment of the small intestine.
•  Its presence causes the release of digestive enzymes and bile from the pancreas and gallbladder, respectively, and also acts as a hunger suppressant. Hence, I cell secretes cholecystokinin hormone.

Gastric inhibitory peptide inhibits gastric acid secretion in the stomach.
Cholecystokinin is a  small intestinal hormone that stimulates the secretion of pancreatic enzymes and bile. Secretin is a small intestinal hormone secreted by epithelial cells od small intestine epithelial cells; stimulates secretion of bicarbonate-rich fluids from the pancreas and liver. Hence Gastric inhibitory peptide, Cholecystokinin, and Secretin hormones regulate the secretion of digestive juices and help indigestion
So, the correct option is 'All of the above'.

Secretin is a hormone that regulates water homeostasis. It is secreted by the duodenum. When hydrochloric acid passes from the stomach into the duodenum, secretin is released. It stimulates the acinar cells of the pancreas to secrete water and bicarbonate into the pancreatic duct. This water and bicarbonate is then drained into the duodenum.

• Gastric inhibitory polypeptide (GIP) or gastro inhibitory peptide, also known as the glucose-dependent insulinotropic peptide, is an inhibiting hormone of the secretin family of hormones. 
• While it is a weak inhibitor of gastric acid secretion, its main role is to stimulate insulin secretion.  
• It is synthesized by K cells, which are found in the mucosa of the duodenum and the jejunum of the gastrointestinal tract. Hence, the GIP  hormone stimulates the lipase activity

• Duocrinin is a postulated gastrointestinal hormone that is liberated by the contact of gastric contents with the intestine and that stimulates the secretory activity of the duodenal glands (Brunner glands). Hence, Duocrinin  the hormone whose secretion is stimulated by the acidic chyme in intestine.

• Secretin stimulates the secretion of a bicarbonate-rich pancreatic fluid. Secretin enters the bloodstream or intestinal lumen and stimulates bicarbonate secretion (by interacting with pancreatic ductal cells), which neutralizes the pH of the gastric chyme upon entering the small intestine.

• GIP  stimulates insulin secretion in response to a meal.
• Gastrin is a peptide hormone that stimulates secretion of gastric acid (HCl) by the parietal cells of the stomach and aids in gastric motility.
• Fatty acids in the lumen of the duodenum stimulate endocrine cells to release the hormone cholecystokinin (CCK). CCK stimulates contractions in the smooth muscle of the gallbladder.
  

CCK is cholecystokinin and secretin are released by duodenum cells and CCK acts upon gallbladder for the secretion of bile while secretin stimulates stomach and they both stimulate the pancreas to secrete enzymes and hydrogen bicarbonate that neutralize acidic chyme.