Which hormone would trigger bile secretion?
The correct answer and explanation is:
The hormone that triggers bile secretion is cholecystokinin (CCK).
Cholecystokinin is a peptide hormone produced by cells in the duodenum, which is the first section of the small intestine. When food, particularly fats and proteins, enters the duodenum, it stimulates the release of CCK. This hormone plays a crucial role in digestion, especially in the digestion of fats.
Upon release, CCK travels through the bloodstream and binds to receptors on the gallbladder, prompting it to contract. This contraction forces bile, which is stored in the gallbladder, into the cystic duct and into the common bile duct. From there, it is released into the duodenum to aid in the emulsification and digestion of fats. Bile contains bile salts, which are essential for breaking down fats into smaller particles, making them easier to digest by pancreatic enzymes.
Cholecystokinin also has other important functions related to digestion. It stimulates the pancreas to release digestive enzymes, which are essential for breaking down proteins, carbohydrates, and fats. Furthermore, CCK has an inhibitory effect on gastric emptying, slowing the movement of food from the stomach to the small intestine, which helps in the proper digestion and absorption of nutrients.
Additionally, CCK promotes satiety by acting on the central nervous system, signaling to the brain that the body has received sufficient food. This is why after eating a meal rich in fats and proteins, the release of CCK not only aids in digestion but also contributes to a feeling of fullness.
In summary, cholecystokinin is the key hormone responsible for stimulating the secretion of bile, ensuring that fats are properly emulsified and digested in the small intestine.