The liver acts as a storehouse for the body, to be called upon as needed. Some of the carbohydrates which during digestion have been converted into sugar, on reaching the liver are changed into glycogen, and glycogen is reconverted into sugar before entering the general circulation.
The digested food is now ready for absorption, although, as has been stated, the digestion of all foods need not be completed before the absorption of some foods take place. For example, alcohol, sugar, and some proteids and salts are absorbed in the stomach.
Food is moved along from the small to the large intestine by peristaltic muscular contraction. Absorption takes place to a small extent in the small intestine, but to a much larger extent in the large intestine.
Bile salts, on account of their great value, are nearly absorbed before reaching the rectum, and are used over and over again. Salts, bile pigments, connective tissue, and cellulose are not digested (although some authorities affirm that the cellulose in young vegetables is partially digested); these, with the waste products of metabolism, are excreted through the rectum as fæces.
