226 



UNCONSCIOUS NERVOUS OPERATIONS 



(two or more arteries, a dense network of capillaries, and 

 one or two veins), connective tissue fibers, and a single 



lymphatic or lacteal ves- 

 sel, which may be looped 

 or branched (Fig. 113). 

 Between blood vessels 

 and lymphatics is a very 

 thin layer of fine muscu- 

 lar fibers, which help to 

 propel the chyle along 

 the lacteals. Fine nerve 

 fibers are also found. In 

 the villi the digested 

 food passes through the 

 cells of the thin wall 

 into blood vessels and 

 lacteals. 



319. The Large Intestine 

 (Fig. 111). The small 

 intestine passes into the 

 large intestine, the ileo- 

 ccecal valve at the junc- 

 tion preventing any re- 



Fig. 113. Diagram of the essential 

 parts of a villus 



a epithelium winch takes up food and 



transports it to the tubes within. 

 b an artery, c capillaries. d a lactea^ 



flux of the contents from 

 the large to the small 

 tube. The large intestine has three parts, called the 

 caecum, the colon, and the rectum. The caecum is a large 

 sac on the right side, which receives the contents of 

 the small intestine. Attached to the lower side of the 

 cjecum is the small vermiform appendix, which has no 

 known function, but is regarded as a " survival " from 

 a previous type of animal structure. Continuous with 

 the ciecum is the colon, having ascend in; j, transverse, and 



