INTESTINES. 



[ 439 



INTESTINES. 



tered, roundish, elongate nuclei, without 

 elastic tissue. Between the proper mucous 

 membrane and the submucous tissue, is 

 situated alayer of longitudinal and transverse 

 unstriped muscular fibres, frequently, how- 

 ever, indistinct in man. 



Fig. 369. 



Magnified 60 diameters. 



Perpendicular section of the wall of the lower part of 

 the ileum of the calf: a, villi ; 6, Lieberkiihn's glands, 

 c, muscular layer of the mucous membrane ; d, follicle 

 of a Peyer's gland; e, subjacent portions of the submu- 

 cous tissue ; /, circular muscular fibres ; g, longitudinal 

 ditto. 



The epithelium of the intestines consists 

 of a single layer of cylindrical cells, con- 

 taining a transparent oval nucleus, with one 

 or two nuclei, and granular matter. 



In the small intestines, the free border of 

 the epithelium-cells presents a broad seam 

 with delicate longitudinal striae, forming 

 the so-called pore-canals. Besides the 

 ordinary cylindrical or columnar cells are 

 certain cup-, or goblet-shaped cells, the open 

 mouths of which are directed towards the 

 cavity of the intestine (PI. 53. fig. 20). It 



is a question whether these goblet-cells are 

 modified epithelium-cells, or represent pe- 

 culiar morphological elements. 



The surface of the small intestines is 

 covered with VILLI, which are absent in the 

 large intestines ; and in every villus one or 

 two spaces are found, constituting the origin 

 of the lacteals. 



The elements of the muscular coat are 

 unstriped muscular fibres, consisting of pale, 

 homogeneous, fusiform, flattened cells, with 

 an elongated nucleus. The fibres fre- 

 quently present knotty expansions, and 

 sometimes zigzag flexuosities. 



The glandular organs of the small intes- 

 tines consist of : Brunner's or the racemose 

 glands; Lieberkiihn's follicles or the tubular 

 glands ; Peyer's, the aggregate or agminate 

 glands ; and the solitary glands or follicles. 



Brunner's glands are situated in the sub- 

 mucous tissue of the duodenum, extending 

 about as far as the orifice of the choledic 

 duct. If a portion of the intestine be kept 

 stretched, or distended with air, and the 

 muscular coat be dissected off, they are seen 

 as yellowish, flattened, roundish-angular 

 bodies, mostly about 1-60 to 1-25" in size, 

 the short ducts of which pass through the 

 mucous membrane. They secrete an alka- 

 line mucous liquid. 



Lieberkiihn's follicles, or the tubular 

 glands (fig. 370), are distributed throughout 



Fig. 370. 



Magnified 60 diameters. 



Lieberkiihn's follicles, from the pig : a, basement 

 membrane and epithelium ; b, cavit 



cavity. 



the small intestines, extending through the 

 substance of the mucous membrane. They 

 are very numerous, straight, narrow, slightly 

 dilated at the ends, and rarely bifurcate. 



