- Minimal secretion between meals
- Entry of food stimulates secretions via neural and humoral mechanisms:
Neural
- Pancreas is innervated by the vagus nerve which releases acetyl choline
- When activated during the cephalic phase of digestion in anticipation of a meal, there is an increase in pancreatic acinar cell activity
Humoral (Hormonal)
Gastrin
- Secreted by the G cells of the stomach in response to gastric distension
- Functions include:
- Stimulation of pancreatic acinar cells to secrete digestive enzymes in preparation for the arrival of carbohydrates, proteins and fats
- Stimulation of gas gastric acid secretion by the parietal cells of the stomach
Cholecystokinin (CCK)
- Secreted by the duodenal mucosal cells in response to fat or protein rich chyme entering the duodenum
- Functions include:
- Increasing the production of bile in the liver
- Stimulation of gallbladder contraction
- Slowing gastric emptying
- Stimulation of the pancreatic acinar cells to secrete digestive enzymes
Secretin
- Secreted by the duodenal mucosa in response to the presence of acid-containing chyme in the duodenum
- Functions include:
- Slowing gastric emptying
- Stimulation of duct cells of the pancreas to secrete HCO ̅ to neutralise chyme