324 



DISSECTION OF THE ABDOMEN. 



composi- 

 tion. 



Arteries of 

 the intes- 

 tine: 



These patches are simply collections of lymphoid nodules of the 

 same nature as the " solitary glands." 



Vessels of the intestine. The arteries are derived from the intestinal 

 branches of the superior mesenteric trunk, and enter the wall of the 

 intestine at the attached border. They run at first beneath the 

 serous coat, round the side of the bowel, and give off numerous 

 ramifications, which anastomose freely together, and perforate the 

 muscular coat, supplying branches to its substance. Finally, they 

 break up into very minute twigs in the submucous layer, before 

 entering the mucous coat. The veins have their usual resemblance 

 to the companion arteries. 



absorbents ; The absorbents (lacteals) leave the intestine with the vessels and 

 pass to the mesenteric glands. 



Nerves of the small intestine come from the upper mesenteric 

 plexus, and entering the coats by the side of the arteries, form 

 plexuses with interspersed ganglia. 



veins 



and nerves. 



Extent of 

 the gut ; 



length ; 



Compared 



more fixed, 

 not coiled, 

 sacculated 



LARGE INTESTINE. 



The large intestine is the part of the alimentary canal between the 

 termination of the ileum and the anus. 



In length it measures about five or six feet, one-fifth of the length 

 of the intestinal tube. The diameter of the colon is largest at the 

 commencement of the csecum, and gradually decreases as far as the 

 upper part of the rectum : in the lower part of the rectum there is a 

 dilatation above the anal canal. 



When compared with the small intestine, the colon is distinguished 

 by the following characters : It is generally of greater capacity, 

 being in some places as large again, and is more fixed in its position. 

 Instead of being a smooth cylindrical tube, the colon is sacculated, 

 and is marked by three longitudinal muscular bands, which alternate 



with bands. witn ftg raany rows O f dilatations. Its wall is thicker and attached to 



ages. n the surface, especially along the transverse and pelvic colon, are small 

 processes of peritoneum containing fat the appendices epiplo'icse. 



The inflated portion of the large intestine, containing the ileo-colic 

 junction, will now be examined. 



The C^CUM, or the head of the colon (fig. 120, a), is the rounded 



Definition of end of the large intestine, which projects, in the form of a pouch, 

 below the entrance of the ileum. It measures about two inches 

 and a half in length, and rather more in width, though gradually 

 narrowing below : it is the widest part of the colon. At its inner 

 side it is joined by the small intestine (6) ; and still lower there is a 

 small worm-like projection (c) the vermiform appendix. 



Appendix vermiformis (fig- 120, c). This little convoluted tube is 

 attached to the lower and hinder part of the csecum, of which it was 

 a continuation at one period in the embryo. From three to six 



dimensions; inches in length, the appendix is rather larger than a goose-quill, 

 and is connected to the inner side of the csecum and to the lower face 



it is hollow, of the mesentery of the ileum by the meso-appendix. Its interior 



length and 

 width ; 



receives 

 ileum and 

 appendix. 



Vermiform 

 appendix : 



attach- 

 ment ; 



