INTESTINES. 



[ 366 ] 



INTESTINES. 



The elements of the muscular coat are 

 organic or unstriped muscular fibres, con- 

 sisting of pale, homogeneous, fusiform, flat- 

 tened cells, with an elongated nucleus. The 

 fibres frequently present knotty expansions, 

 and sometimes zigzag flexuosities. 



The glandular organs of the small intes- 

 tines consist of Brunner's or the racemose 

 glands; Lieberkuhn'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 1-50 to 1-25" in size, 

 the short ducts of which pass through the 

 mucous membrane. They secrete an alkaline 

 mucous liquid. 



Lieberkuhn's follicles, or the tubular 

 glands (fig. 3/4), are distributed throughout 



Fig. 374. 



Magnified 60 diameters. 



Lieberkuhn's follicles, from the pig. a, basement 

 membrane and epithelium j b, 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. 

 They vary in length from 1-60 to 1-84", and 

 consist of a delicate basement membrane, 

 lined with epithelium. 



Peyer's glands are rounded or elongated 

 flattened aggregations of glands, appearing 

 upon the inner surface of the intestine as 

 slightly depressed spots. They are most nu- 



merous in the ileum, but are sometimes found 

 Fig. 375. 





Magnified 10 diameters. 



Portion of a Peyer's gland, human, a, follicles sur- 

 rounded by the orifices of Lieberkuhn's glands ; b, villi ; 

 c, scattered Lieberkuhn's glands. 



in the lower part of the jejunum, or even its 

 upper part and the duodenum. They are 

 usually twenty, thirty, or more in number. 

 They vary in length from 1-25 to H". Each 

 consists of an aggregation of closed and 

 rounded follicles, from 1-70 to 1-12" in 

 diameter, partly seated in the mucous mem- 

 brane itself, partly in the submucous tissue. 

 The follicles are surrounded by a ring of 

 Lieberkuhn's glands, which, with villi, also 

 occupy the intervening portion of the mucous 

 membrane. Each follicle consists of a tole- 

 rably firm coat of indistinctly fibrous areolar 

 tissue, with scattered nuclei, enclosing a grey 

 soft substance, consisting of innumerable 

 nuclei and cells, from 1-3000 to 1-1500" in 

 diameter, with a few granules of fat. The 

 follicles are surrounded by a vascular net- 

 work, which sends off branches to their 

 interior. 



The solitary glands agree in structure with 

 the individual follicles of Peyer's glands. 

 Their free surface is usually convex, and 

 covered with villi (fig. 376). 



Fig. 376. 



Solitary gland, covered with villi, from the jejunum. 



The glandular organs of the large intes- 

 tines are Lieberkuhn's glands and the solitary 

 follicles. 



The Lieberkuhn's glands agree in struc- 



