Final answer:
The entry of chyme into the duodenum triggers a neural reflex that stimulates the gallbladder to contract, releasing bile. This process is controlled by the hormone cholecystokinin (CCK).
Step-by-step explanation:
A neural reflex stimulated by the entry of chyme in the duodenum stimulates contraction of the gallbladder, resulting in the release of bile. This process is regulated by the hormone cholecystokinin (CCK), which stimulates the gallbladder to contract and the pancreas to release pancreatic lipase, aiding in the digestion of fats. Bile helps to emulsify fats, making them more accessible to the water-soluble enzymes that break them down into smaller particles.