Page:Structure and functions of the body; a hand-book of anatomy and physiology for nurses and others desiring a practical knowledge of the subject (IA structurefunctio00fiskrich).pdf/148

 allows great freedom of motion, so that there is little fixation to the loops of the small intestines.

The Small Intestine.—The small intestine opens out of the stomach and has three divisions: 1. the duodenum, which is only about ten to twelve inches long; 2. the jejunum, so called because it is generally empty after death, which is about two-fifths of the remainder and lies chiefly in the umbilical region and the left iliac fossa, and 3. the ileum or curved intestine, the remaining three-fifths, which gets its name from its numerous coils and which lies in the middle and the right side of the abdomen. There is no direct division between the jejunum and the ileum, but the first part of the former and the last part of the latter are quite different in character. At its entrance into the large intestine the ileum is guarded by the ''ileo-cecal valve''.

The same coats continue in the small intestine as were found in the stomach, but they are here much thinner and the inner coat is shaggy, like velvet, with innumerable minute processes called villi, which greatly increase the absorbing surface. In fact, the great length of the intestine as well as the presence of the villi is aimed to provide a large surface to absorb the food as it passes, an even greater increase of surface being provided by the fact that the intestinal wall is thrown into folds, the valvulæ conniventes. Each villus is covered with a layer of columnar epithelial cells and has within connective tissue, in which are found a fine capillary network and open lymph spaces from which leads a single lacteal vessel.

—1, Central lacteal; 2, capillary network; 3, columnar cells.

Closely connected with the lymphatic vessels are the solitary glands, small round bodies the size of a small pin's head. Peyer's glands or patches are patches of solitary glands opposite the mesenteric attachment and are largest and most numerous in the ileum. In typhoid fever they are involved and may become the seat of