THE ABSORPTION OF FOODS 



119 



ately around the body, the various tissues would have an 

 over-supply of foods for a few hours, and after that, until 

 the next meal time, there would be a scarcity. This would 

 be a very faulty method of nutrition, since most of the 

 tissues are doing as much work at one time of the day as 

 at another, and so need food all the time. 



The Liver as a Storehouse for Carbohydrates. To prevent 

 this irregular supply of food to the tissues is one of the duties 

 of the livex. As the food-laden blood passes through it, a large 

 part of the sugar is changed into a compound called glycogen, 

 and left stored in the liver cells; Fig. 66. Its chemical make- 

 up is the same as that of veg- 

 etable starch. The blood, 

 with a small load of sugar 

 leaves the organ, other food 

 substances having under- 

 gone no change. After 

 the food of one meal 

 has been absorbed from 

 the intestine, the liver 

 begins, little by little, to 

 dole out to the blood this 

 stored sugar so that the 

 latter, circulating about the body, contains at all times 

 about the same amount. This uniform supply is necessary 

 for the best health and most efficient activity of the body 

 organs. Too much or too little sugar in the blood is injurious. 

 Thus while the bile secreted by the liver is of little use in 

 digestion, the liver is itself a highly important organ, as a 

 regulator of the food supply to the blood. 



PATH TAKEN BY THE FATS 



The fats pass into the lacteals of the villi and these open 

 into larger vessels in the walls of the intestine, which in turn 

 unite with others to form still larger ones (of about the size of 



FIG. 66. LIVER CELLS 

 Loaded with glycogen which they have 

 made out of sugar taken from the blood. 

 (Modified from Frerichs) 



