358 THE HUMAN BODY AND ITS FOOD 



great as if it were smooth. Each villus contains a net- 

 work of small blood tubes (capillaries), and also the 

 lacteals. The "food solution/' called chyle, which the 

 small intestine prepares, goes into the epithelial cells of 

 the villi, and from these cells the blood tubes and lacteals 

 absorb it. The lacteals absorb only the digested fats; 

 the blood tubes absorb the other kinds of food. 



Between the small intestine and the large one there is a narrow 

 opening which allows food to pass. The large intestine begins at the 

 level of the right hip, passes up the right side to the diaphragm, then 

 across the abdomen to the left side, and down the left side. It does 

 some of the work of absorption, although it has no villi; but its chief 

 use is to discharge the solid waste from the body. It takes about 2 

 days, under normal conditions, for food to pass the length of both 

 intestines. 



The vermiform appendix, which when inflamed produces appendi- 

 citis, is in the large intestine, near the place where the small intestine 

 and large intestine unite. It is a small, closed tube, about % of an 

 inch in diameter, and about 2 inches long. 



366. The Liver. The liver is a dark-red organ weigh- 

 ing about 4 pounds (Fig. 282). It is on the right side of 

 the abdomen, under the lower ribs (see also Fig. 273, 

 350). The liver has several very important functions. 

 For one thing, it helps to remove from the blood the waste 

 nitrogen compounds formed by the destruction of the 

 cells. A second function of the liver is to make and 

 to store glycogen, a starchlike substance that is readily 

 changed to sugar when the body needs it. A third use 

 of the liver is to secrete bile, a yellow, bitter liquid, which 

 is emptied by the bile tube into the small intestine. 



The bile is collected from the blood by a multitude of bile ducts. A 

 tube leads from the liver to the gall bladder, a sac that receives and 



