Test Your Knowledge of Pancreatic Function!

Study Notes

The pancreas is a long, skinny gland located in the upper abdomen, behind the stomach.
The pancreas has endocrine functions, meaning it secretes hormones into the blood that eventually act upon other target tissues.
Approximately 90% of the pancreas is dedicated to its exocrine functions, which include producing enzymes and fluids that help neutralize and digest food within the intestines.
The acinar cells in the pancreas make digestive enzymes, which are released into the pancreatic duct and delivered to the small intestine.
The zymogens needed for activation are kept away from sensitive organelles in storage vesicles called zymogen granules, and are packaged with protease inhibitors.
The zymogens are released into the pancreatic duct and activated by protease trypsin.
Trypsin is a pancreatic digestive enzyme that is initially produced as the zymogen trypsinogen.
Normally, trypsinogen isn't activated until it is cleaved by protease enteropeptidase.
The secretions of the ductal cells are filled with various ions, particularly sodium, potassium, chloride, and bicarbonate.
The concentrations of sodium and potassium are about the same as the concentrations in the plasma, whereas the concentrations of chloride and bicarbonate depend on the pancreatic flow rate.
When you eat a pizza, the sight and smell of the food stimulates the vagus nerve which sends signals to the pancreas.
The vagus nerve secretes the neurotransmitter acetylcholine which stimulates muscarinic receptors on acinar cells and causes them to secrete enzymatic fluid.
Next, is the gastric phase, which is when the chewed up pizza enters the stomach and makes it distend. Distention is sensed by mechanoreceptors in the stomach wall.
This afferent information travels through the vagus nerve to the brain which sends efferent signals back through the vagus nerve to the pancreas.
The result is that the acinar cells produce slightly more fluid.
Finally, there’s the intestinal phase which is responsible for over 80% of pancreatic secretions.
Partially digested food arriving from the stomach is acidic and when it enters the duodenum, the rise in acidity signals S cells that line the duodenum to release secretin.
Secretin acts on secretin receptors on the ductal cells to massively increase secretion of the aqueous portion of the pancreatic fluid which is high in bicarbonate, and therefore helps to neutralize the acidic chyme.
When food eventually reaches the ileum and colon, neuroendocrine cells secrete the hormone peptide YY which help inhibit pancreatic secretion.

Description

Do you know what the pancreas does? The pancreas is a long, skinny gland located in the upper abdomen, behind the stomach. It has endocrine functions, meaning it secretes hormones into the blood that eventually act upon other target tissues. The pancreas has two main functions: producing enzymes and fluid for digestion in the small intestine and secreting the hormone peptide YY which helps to inhibit pancreatic secretion.