Question

Cholecystokinin is a
A. Bile pigment
B. Enzyme
C. Lipid
D. Gastrointestinal hormone.

Answer 1

Cholecystokinin (CCK) is secreted by the small intestineand is responsible for food digestion and stimulates gastrointestinal secretions.

Step by step answer: Cholecystokinin commonly denoted by CCK was formerly known as pancreozymin. It is a digestive hormone which means they are used for digestion. This hormone is secreted with another hormone, secretin. When food from the stomach reaches the duodenum, the production of these hormones is stimulated. A few years before, cholecystokinin and pancreozymin were considered two separate hormones due to their distinct action. The role of pancreozymin was to release enzymes from the pancreas. The role of cholecystokinin was considered the contraction of the gallbladder which forces bile into the duodenum. However, both the actions are considered to be done by cholecystokinin only. Cholecystokinin is produced by the cells of the upper small intestine or the duodenum. Its production is stimulated by the introduction of hydrochloric acid or gastric acid, amino acids, and fatty acids into the stomach or duodenum. Cholecystokinin stimulates the gallbladder to contract and release the stored bile juice into the intestine in order to digest the food. It also stimulates the secretion of pancreatic juice in the intestine and is also considered to induce satiety. Satiety is referred to as the feeling of being full. Among many hypotheses related to inducing satiety, one hypothesis is that meal-induced secretion of cholecystokinin activates the satiety center present in the hypothalamus located in the base of the brain. Another hypothesis is that the feeling of fullness could be caused due to distension of the stomach as cholecystokinin inhibits gastric emptying.
So, the correct option is option D

Note: In our body, there are four major gastrointestinal hormones secreted. They are secretin, cholecystokinin, gastrin, and somatostatin. Secretin regulates the production of gastric acid and is responsible for osmoregulation. Gastrin is also responsible for hydrochloric acid secretion. Somatostatin is responsible for inhibiting the production of other hormones.