Major GI Hormones and Their Related Functions

Question 1

Gastrin

Answer 1

Site of Production: Stomach

Stimuli for Release: - food in stomach

• stretching of the stomach walls
• alcohol
• caffeine
• cephalic stimuli (taste, smell)

Major Activities: - Stimulates Gastic Motility

• Stimulates secretion of gastric juice
• Increases gastric emptying

Question 2

Secretin

Answer 2

Site of Production: Small Intestine

Stimuli for Release: - Arrival of chyme into the duodenum

Major Activities: - Inhibits gastric motility

• Inhibits secretion of gastric juice
• Stimulates release of pancreatic juice containing sodium bicarbonate and enzymes

Question 3

Cholecystokinin (CCK)

Answer 3

Site of Production: Small Intestine

Stimuli for Release: Arrival of partially digested protein and fat into the duodenum

Major Activities: Stimulates gallbladder to contract and release bile
-Stimulates release of pancreatic enzymes

Question 4

Ghrelin

Answer 4

Site of Production: Stomach (and other tissues)

Stimuli for Release: Not well understood, but release is greater during fasting

Major Activities: Stimulates hunger