Morphology and physiology of digestive epithelia in Decapod crustaceans.

The anatomy and cellular composition of the digestive tract of decapod crustaceans is in many aspects considerably different from the vertebrate system. These differences include primarily the gastric mill and a sophisticated filter apparatus in the stomach and the hepatopancreatic tubule system with its bi-directional movement of fluids. Further differences are the lack of a strongly acidic pH and pepsin in the stomach. Consequently, many of the physiological processes are fundamentally different as well, particularly the physical and chemical processing of the feed and the synthesis, storage and mode of action of the digestive enzymes. The hepatopancreas is a central organ of metabolism and includes functions which, in vertebrates, are confined to intestine, liver and pancreas.