268 



PRACTICAL HISTOLOGY. 



[xxiv. 



connective tissue, and under this two or three thin layers of non- 

 striped muscle the muscularis mucosse. The clear layer of con- 

 densed tissue is not present in the rabbit, dog, or man. 



(6.) The submucous coat, composed of loose connective tissue, 

 with large blood-vessels and a few fat-cells. If the mucous 



membrane be folded and rugaB are 

 present, the connective tissue will 

 be seen to run up into the folds. 



(c.) The muscular coat consists 

 of two or three layers of smooth 

 muscular fibres. The appearance 

 varies according to the manner in 

 which the plane of the section 

 cuts them, for the stomach has 

 an outer longitudinal and an inner 

 circular, and in some places an 

 oblique muscular coat. 



(d.) Outside all a thin layer 

 peritoneum or serous coat con- 

 sisting of fibrous tissue covered by 

 a layer-of endothelium. 



(e.) (H) Study specially the 

 mucous coat. Observe the 

 columnar epithelium lining the 

 stomach, and dipping into the 

 mouths and lining the ducts, 

 which are slightly funnel-shaped. 

 The cells are tall and narrow, and 

 if the section be not too thin, the 

 ends of them may be seen as 



111 i i i G i 



very small, clear, sharply-defined, 

 polygonal areas. As they secrete 

 mucus, they have been called mucous cells. The upper two-thirds 

 or so of the cell is much clearer than the lowest third, which tapers 

 somewhat, and is more granular. Each cell contains an oval nucleus 

 in its lowest third, i.e., near its attached end. 



(/.) Select a fundus gland (fig. 257). Trace its duct down- 

 wards, and note that perhaps it is common to two secretory 

 portions. In the true secretory part, note the large ovoid, border, 

 parietal, or outer cells, lying next the basement membrane, ovoid 

 in shape, granular in appearance, and containing an ovoid nucleus. 

 They do not form a continuous layer, but bulge out the basement 

 membrane here and there. At the upper part of the gland-tube the 

 parietal cells are smaller, and placed nearer each other, while 

 towards the fundus or base of the gland they are larger and further 



Serosa. !_ _____ / ^, -^I____ 



FIG. 256. V.S. Wall of Human Stomach. 

 E. Epithelium ; G. Glands ; Mm. Mus- 

 X is- 



