Jinsh

Glucose, fructose, galactic, and certain pentose are freely absorbed from the intestines and are found in the blood immediately after their absorption. All of them can be detected in the tissues of animals, whether the animals are fed the fasted. In the pat absorptive state, however, glucose alone is found in the Free State in appreciable quantities in blood or tissues. Moreover, the injections and ingestion of any one of the hexodes increase the quantity of glucose or its polymer, glycogen, in the body. This fact indicate these hexodes can be derived from and converted to glucose, which is the form in which carbohydrate is transported and the general medium of exchange in its metabolism. The tissues of the normal animal always contain fructose; but only in the form of esters of phosphoric acid, intermediary products in the metabolism of carbohydrate. Galactic is found in lactose of milk, but for this purpose it is formed in the mammary glands from glucose or its products. It is also a component of certain lipids, the cerebrosides. Pentose, constituents of nucleic acids, is also derived from glucose.

The disaccharides cannot be absorbed from the intestines until they have been hydrolyzed by pancreatic amylase (ptyalin, salivary amylase, usually plays an insignificant role in human digestion) into their component monosaccharide.