Accessory Digestive Organs Quiz

9 Questions

What does cholesterol ester hydrolase (cholesterol esterase) convert cholesterol ester into?

Both fatty acids and free cholesterol

What activates Phospholipase A?

Trypsin

What is the small coenzyme that facilitates the digestive action of pancreatic lipase on fats?

Colipase

Pancreatic juice with large quantity of bicarbonate is acidic in nature.

False

What are the essential accessory digestive organs, besides teeth, tongue, and salivary glands, for digestion?

Pancreas, liver, and gallbladder

What is the function of the pancreas?

The function of the pancreas is to produce enzymes that break down all categories of digestible foods and secrete hormones that affect carbohydrates metabolism.

Pancreatic juice has a highly acidic pH of 3 to 4.

False

Pancreatic lipase digests triglycerides into _ and _ acids.

monoglycerides, fatty

Match the following pancreatic enzymes with their functions:

Trypsin = Digestion of proteins Chymotrypsin = Digestion of proteins Carboxypeptidases = Break terminal bonds of protein molecules Elastase = Digests elastic fibers Collagenase = Digests collagen

Study Notes

The Pancreas

The pancreas is an essential organ for digestion, located posterior to the stomach and in close association with the duodenum.
It is a 15-25 cm elongated organ in the abdomen, located retroperitoneally, with three regions: head, neck, and body.
The pancreatic duct runs the length of the pancreas and empties into the second part of the duodenum at the ampulla of Vater.

Blood Supply and Venous Drainage

The pancreas is supplied arterially by the pancreatico-duodenal arteries, which are branches of the superior mesenteric artery and the hepatic artery.
Venous drainage is via the pancreatic duodenal veins, which end up in the portal vein.

Functions of the Pancreas

The pancreas produces enzymes that break down all categories of digestible foods (exocrine pancreas) and secretes hormones that affect carbohydrate metabolism (endocrine pancreas).
The pancreas is composed of pancreatic exocrine cells, whose ducts are arranged in clusters called acini.

Pancreatic Secretions

Pancreatic secretions contain bicarbonate ions and are alkaline, with a pH of 8 to 8.3, to neutralize the acidic chyme from the stomach.
The two major proteases of the pancreas are trypsinogen and chymotrypsinogen, which are activated by enterokinase in the intestine.

Control of Pancreatic Secretions

Control of the exocrine function of the pancreas is via the hormone gastrin, cholecystokinin, and secretin, which are secreted by cells in the stomach and duodenum in response to distension and/or food.

Islets of Langerhans

The islets of Langerhans are clusters of endocrine cells that produce hormones such as insulin, glucagon, somatostatin, and pancreatic polypeptide.

Secretion of Pancreatic Enzymes

Pancreatic enzymes are synthesized in ribosomes, which are attached to the endoplasmic reticulum of acinar cells in the pancreas.
The raw materials for the synthesis of pancreatic enzymes are amino acids, which are derived from the blood.

Pancreatic Juice

Pancreatic juice contains 99.5% water and 0.5% solids, including organic and inorganic substances.
The bicarbonate content of pancreatic juice is very high, making it highly alkaline, which protects the intestinal mucosa from acid chyme.

Functions of Pancreatic Juice

Pancreatic juice has digestive functions, including the digestion of proteins, lipids, and carbohydrates, and neutralizing action, which protects the intestine from acid chyme.