1 634 



HUMAN ANATOMY. 



circumference is greatest in the duodenum (not always at the same point), beyond 

 which it gradually decreases, the diameter of the gut at its lojver end being nearly 

 one-third smaller than at the beginning. Since certain structural features are com- 

 mon to the entire small intestine, it will be convenient to consider these in this place, 

 further details being given with the descriptions of the special parts. 



Fig. 13S3. 



..-^-^ 



Liver 



Gall-bladdtr — ^ 



Transverse colon 



Ascending, 

 colon 



Ileum 



Falciform ligament 



— Stomach 



Greater omentum (cut 

 surface) 



Coils of jejunum 



Descending colon 



Sigmoid flexure 



Abdominal organs of formalin subject. Stomach was unusually large, giving an exaggerated impression of its 



transverse position. 



Structure. — The small intestine, as other parts of the alimentary tube below 

 the diaphragm, consists of four coats, the mucous, the submucous, the muscular, and 

 the serous. 



The mucous coat, in addition to the glandular structures, possesses folds and 

 villi that not only greatly increase its surface, but also contribute peculiarities which 

 aid in differentiating between typical portions taken from various regions. The 



