Final answer:
The liver produces bile, which is secreted into the duodenum for fat digestion and neutralizing stomach acidity. The gallbladder stores and secretes bile, while secretin and CCK regulate the release of bile and digestive enzymes from the pancreas.
Step-by-step explanation:
The liver produces bile that it secretes into the duodenum via the bile duct to aid in digestion, particularly in emulsifying fats. The gallbladder then stores the excess bile not immediately needed for digestion. Hepatocytes in the liver are continuously producing bile, but it is during the presence of fatty chyme in the duodenum that bile production is increased, responding to the gut hormone secretin. Bile excretion is necessary for the proper breakdown of lipids, making fats more amenable to digestive enzymes like lipase, and also plays a role in neutralizing acidic chyme coming from the stomach.
Digestive secretions from the liver, pancreas, and gallbladder converge in the duodenum, the first section of the small intestine. Here, enzymes and bicarbonate reduce the chyme's acidity, and the enzymatic breakdown of carbohydrates, proteins, and lipids continues. The release of bile into the duodenum is stimulated by cholecystokinin (CCK) while secretin promotes the delivery of alkaline bicarbonate solution from the pancreas.