160 



ANATOMY FOR NURSES. 



[CHAP. XIV. 



of two kinds, and secrete mucus, and the special secretion of 

 the stomach, the gastric juice. The stomach is supplied with 

 nerves from the sympathetic system, and also with branches 

 from the pneumogastric nerve, which comes from the cerebro- 

 spinal system. 



The small intestine. The small intestine fills the greater 

 part of the front of the abdominal cavity. It is about twenty 

 feet long, two inches wide at its gastric end, and narrows to 

 nearly one and a quarter inches where it 

 joins the large intestine. The small intes- 

 tine is divided by anatomists into three 

 portions. The first ten or twelve inches 

 is called the duodenum ; the succeeding 

 two-fifths, the jejunum; and the rest, the 

 ilium. The intestines are invested by a 

 fold of the peritoneum in much the same 

 way as the stomach. In this situation, the 

 fold of the peritoneum is called the me- 

 sentery, and between its two layers are 

 numerous blood-vessels, lymphatics, and 

 lymphatic glands. 



The muscular coat of the small intestine 

 has only two layers : an outer, thinner and 

 longitudinal; and an inner, thicker and 



. 6 



circular. 



xhe mucous coat is highly developed. In 



ved 



FIG. 98. AN INTES- 



TINAL VILLUS. a, a, a, 

 columnar epithelium; 



6, 6, capillary network; ... -, i . 



c, c, lymphoid tissue the tirst place it is largely increased by 

 fibfeS; *' bein arran ge<l in permanent folds, the 

 valvulse conniventes (vide Fig. 97), which 

 project transversely into the interior of the tube. The onward 

 course of the food is delayed by being caught in the hollows 

 formed by these folds, and thus more thoroughly subjected to 

 the action of the digestive juices : this arrangement also affords 

 a larger surface for absorption. The valvulse conniventes are 

 not found in the beginning of the duodenum, but begin to 

 appear one or two inches from the pylorus ; about the middle 

 of the jejunum they begin to decrease in size, and in the lower 

 part of the ilium they almost entirely disappear. 



Again, the surface of the mucous membrane is increased by 

 the finger-like projections which are so close set as to give a 



