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THE VITAL PROCESSES 



2. A small lymph tube, called a lacteal, which occupies 

 the center of the villus and connects at the base with other 

 lymph tubes, also called lacteals (B, Fig. 76). 



3. A network of capillaries. 



The villi are structures especially adapted to the work of 

 absorption, and they are found only in the small intestine. 



FIG. 76. The villi. A. Diagram of a small section of mucous mem- 

 brane of small intestine. I. Villi. 2. Small glands, called crypts. 



B. Diagram showing structure of villi. I. Small artery. 2. Lacteal. 

 3. Villus showing termination of the lacteal. 4. Villus showing capillaries. 

 5. Villus showing both the lacteal and the capillaries. 6. Small vein. 

 7. Layer of epithelial cells. 



The mucous membrane in all parts of the canal, however, 

 is capable of taking up some of the digested materials. 



Work of Capillaries and Lacteals. The capillaries and 

 lacteals act as receivers of material as it passes through 

 the layer of epithelial cells covering the mucous mem- 

 brane. The lacteals take up the digested fats, 1 and the 

 capillaries receive all the other kinds of nutrients. These 

 vessels do not, of course, retain the absorbed materials, 

 but pass them on. Their final destination is the general 

 circulation, which they reach by two well-defined channels, 

 or routes. 



Routes to the Circulation. The two routes from the 



1 The lacteals (from the Latin lacteus, milky) are so called on account of their 

 appearance, which is white, or milk-like, due to the fat droplets. 



