Question

The hormone that stimulates the release of pancreatic juice is
a. Secretin
b. Glucagon
c. Inhibin
d. Insulin

Answer 1

The pancreas is a major part of the digestive system required for proper digestion and is located in the visceral region. They are alkaline in nature due to the high concentration of bicarbonate ions. Bicarbonate helps in neutralizing the acidic gastric acid, and allows enzymatic changes.

Complete answer:
The pancreas secretes a liquid called pancreatic juice which contains enzymes trypsinogen, elastase, carboxypeptidase, pancreatic lipase. Pancreatic juice is produced by the walls of the duodenum, and by the action of autonomic innervation is regulated by the hormones secretin and cholecystokinin. The hormones are released into the blood and are stimulated by the entry of the acidic chyme into the duodenum. The pancreas receives autonomic innervation.

The blood flow is regulated by sympathetic nerve fibers, while parasympathetic neurons stimulate the activity of acinar and centroacinar cells. The release of pancreatic juice is stimulated by secretin. Gastrin is secreted by pancreatic juice into the duodenum through duodenal papilla which in turn promotes stomach-churning and induces more release of gastric juices.

The endocrine cells secrete secretin and cholecystokinin of the duodenal wall in response to the presence of hydrochloric acid in chyme and that of fatty food respectively. Secretin induces the release of pancreatic juice from the pancreas while cholecystokinin induces contraction of the gallbladder to release stored bile.

Insulin and glucagon regulate blood sugar levels. Secretin inhibits the secretion of gastric acid from the parietal cells of the stomach by regulating the pH of the duodenum and stimulates the production of bicarbonate from the ductal cells of the pancreas. It stimulates bile production by the liver, the bile emulsifies dietary fats in the duodenum so that pancreatic lipase can act upon them.

Prosecretin is a precursor to secretin, which is present indigestion. Secretin is stored precursor form and is activated by gastric acid. This indirectly results in the neutralization of duodenal pH. The secretion of secretin is increased by protein digestion, secretin release is inhibited by H2 antagonists, and reduces gastric acid secretion. Secretin cannot be released if the pH in the duodenum increases above 4.5. Glucagon is produced by alpha cells and controls the blood sugar level in blood.

Inhibin is produced by gonads and it inhibits the FSH (Follicle Stimulating Hormone). Insulin is a hormone produced by the pancreas and it allows the body to use glucose for energy metabolism.

Hence the hormone that stimulates the release of pancreatic juice is secretin.
So, the correct answer is option (A).

Note: Secretin helps to neutralize the pH in the duodenum, it increases water and bicarbonate secretion. It modulates water and electrolyte transport in pancreatic cells. It stimulates adenylate cyclase activity and converts ATP to cyclic AMP. Secretin induces the release of the pancreatic juice from the pancreas it induces the contraction to release the stored bile.