1 68 ANATOMY AND PHYSIOLOGY 



Peptones and their products, amino-acids, also find their way in the same 

 manner to the portal blood and the liver, from the intestine. 



Thus it appears that all proteins, sugars, water and salts pass 

 through the liver. There, water and salts are used for various 

 combinations; sugars are converted into glycogen to a great extent 

 and stored for future use; and proteins furnish tissue food and 

 materials for bile. 



Glycogen. This product of the action of liver cells upon carbohydrates is 

 stored in the liver. When needed it is returned to the blood (as sugar again) 

 and distributed to the tissues, notably to the muscles. Being readily oxidized 

 it favors the rapid changes in muscles which result in motion. Therefore, it 

 follows that sugar and starch are sources of muscle energy. 



Lacteal s 

 Blood vessels 



%^w : ; 



FIG. 114. LOOP OF SMALL INTESTINE WITH LACTEALS. (Morris.) 



Urea. This is another substance which appears as a result of the activity 

 of the liver cell. It is one of the final forms of waste derived from the 

 metabolism of protein substances. It is a very poisonous waste and is elim- 

 inated from the blood by the kidneys. 



Having yielded materials for these functions, the remaining 

 food substances are carried away from the liver by hepatic veins 

 and finally into the general circulation, to be distributed to the 

 tissues of the body. 



There remain the fats: These, being transferred by the epithe- 

 lial cells to the lymph-spaces, take the other route, in the form of 

 an emulsion known as chyle. They pass into the lymph capillaries 



