Which hormone triggers the gallbladder to release bile for fat digestion?

Which hormone triggers the gallbladder to release bile for fat digestion?

• A. Cholecystokinin (CCK)
• B. Secretin
• C. Gastrin
• D. Somatostatin

Answer: (A)

Fat entering the small intestine signals a hormone to tell the gallbladder to contract and release bile needed for digesting fats. This hormone is cholecystokinin (CCK). I cells in the lining of the duodenum and jejunum release CCK in response to fatty acids and some amino acids in the chyme. When CCK enters the bloodstream, it stimulates the gallbladder to contract and relaxes the sphincter of Oddi, letting bile flow into the small intestine to emulsify fats. CCK also prompts the pancreas to release digestive enzymes, aiding fat digestion. Secretin, released by S cells in response to acidic chyme, mainly prompts the pancreas to secrete bicarbonate-rich fluid to neutralize acid and does not trigger bile release. Gastrin stimulates gastric acid secretion in the stomach, not bile release. Somatostatin generally inhibits several GI secretions, including gastrin and CCK, so it doesn’t drive bile release.

Fat entering the small intestine signals a hormone to tell the gallbladder to contract and release bile needed for digesting fats. This hormone is cholecystokinin (CCK). I cells in the lining of the duodenum and jejunum release CCK in response to fatty acids and some amino acids in the chyme. When CCK enters the bloodstream, it stimulates the gallbladder to contract and relaxes the sphincter of Oddi, letting bile flow into the small intestine to emulsify fats. CCK also prompts the pancreas to release digestive enzymes, aiding fat digestion.

Secretin, released by S cells in response to acidic chyme, mainly prompts the pancreas to secrete bicarbonate-rich fluid to neutralize acid and does not trigger bile release. Gastrin stimulates gastric acid secretion in the stomach, not bile release. Somatostatin generally inhibits several GI secretions, including gastrin and CCK, so it doesn’t drive bile release.