260 



HISTOLOGY. 



RENAL PELVIS AND URETER. 



The renal pelvis and ureter both consist of a mucosa (and submucosa), 

 muscularis and adventitia (Fig. 294). The mucosa includes the epithelium 

 and tunica propria, the latter blending with the submucosa. In sections 



i 



Cylinder cells with 

 a cuticular border. 



Leucocyte. 



Tunica propria. 



FIG. 295. VERTICAL SECTION OF THE Mucous MEMBRANE OF A HUMAN BLADDER. X 560. 



the epithelium resembles that of the moderately contracted bladder (Fig. 

 295), and its cells when found detached in urine are not distinguishable 

 from bladder cells. The epithelium is stratified but consists of few layers. 

 The basal cells are rounded, those of the middle layer are club shaped 

 or conical with rounded ends, and the outer cells are columnar, cuboidal, 

 or somewhat flattened. Their lower surface may be 

 indented by the rounded ends of several underlying 

 cells, as is particularly the case in the contracted blad- 

 der (Fig. 296). Two nuclei are often found in a 

 superficial cell and in some animals they are known to 

 arise by amitosis. Leucocytes frequently enter the 

 epithelium. In some animals mucous glands have 

 been found extending into the tunica propria, and 

 there are gland-like pockets in man. Some of these 

 have no lumen and it is said that none are true glands. 

 Capillary blood vessels, which are abundant in the 

 mucosa, are found directly beneath the epithelium and 

 present the deceptive appearance of becoming .intra- 

 epithelial. The tunica propria consists of fine connective or reticular tis- 

 sue with few elastic fibers. It contains many cellular elements and some 

 leucocytes and passes without a definite boundary into the loose connective 

 tissue of the submucosa. 



FIG. 296. A SUPER- 

 FICIAL EPITHELIAL 

 CELL AND Two 

 CLUB-SHAPED CELLS 

 FROM A CONTRACTED 

 BLADDER. (Koel- 

 liker.) 



