Small Intestine. 



27 



356. Termination of 



the Ileum into the 

 355. Termination of the Coecum, in a Foetus 

 Ileum into the Coecum, in o f 7 months. Natural size 



an Adult. l / t nat. size of an inflated of an inflated and dried in- 

 and dried intestine, the anterior wall testine, the posterior wall being 

 being partially removed. partially removed. 



The mucous membrane of the small intestine contains 

 transverse folds, Valvulae conniventes Kerlcringii, which begin at the 

 descending portion of the duodenum and are thence present throughout 

 the rest of the small intestine; in the duodenum they are largest and 

 most numerous, and from there they diminish gradually in size and number. 

 In the descending portion of the duodenum, near the inner margin 

 of the posterior wall , is a vertical projection, Plica longitudinal is, 

 formed by the mucous membrane raised up by the united Ductus 

 ckoledochus and pancreaticus, before they open into the intestine. Where 

 the ileum opens into the coecum, the mucous membrane forms the ileo- 

 coecal valve, Valvula coli, which consists of two folds. 



Throughout the whole extent of the mucous membrane of the small 

 intestine there are numerous minute processes, Villi intestinales ; each 

 villus has abundant bloodvessels and one or more lymphatic vessels, 

 being supported and held together by retiform lymphoid tissue. 



