Page:Laboratory Manual of the Anatomy of the Rat (Hunt 1924).djvu/97

Rh domen between the kidneys and at the left of the inferior vena cava.

The pancreas secretes a digestive fluid, the pancreatic juice, which contains three enzymes, trypsin, steapsin, and amylopsin. The gastric juice of the stomach contains pepsin which reduces protein food substances to soluble peptones. These, in turn, the trypsin breaks down into amino acids, which are absorbed in the intestines. Steapsin decomposes fats into fatty acids and glycerin. Amylopsin reduces all digestible carbohydrates to glucose, which is absorbed and stored in the liver as glycogen.

The pancreas of the rat is irregular in shape and divided into many large and small lobes. Some of these lobes anastomose with each other. The pancreas is suspended in the descending limb of the great omentum, and throughout the mesoduodenum. It bends dorsally in the mesen- terial junction of these membranes, and also sends a lobe to the pyloric region of the stomach. Its left end is dorsal to the spleen. Pancreatic tissue lies close against the mesenterial side of the duodenum throughout the duodenal loop.

The pancreatic juice enters the bile duct, as it crosses the pancreas, through several small ducts. The openings of these ducts into the bile duct may be seen if the latter is slit and its inner surface examined under the dissecting microscope. The bile duct conducts the pancreatic juice, with the bile, to the duodenum. These ducts are identified with difficulty unless a careful dissection be executed using a microscope.

Exercise XXI. Make an enlarged drawing of the opened abdominal cavity, showing as many as possible of the contained organs and mesenteries.