206 



SPECIAL HISTOLOGY. 



much condensed as to be apparent on the most superficial 

 inspection, or even, more or less to compress the tubuli uriniferi. 

 The additional elements consist chiefly of a fibrinous exudation, 

 presenting various stages of transition into connective tissue, 

 partly also of such forms as are peculiar to immature normal 

 connective tissue, as fusiform cells, &c. In the case of the 

 Malpighian bodies, these new formations present the form of 

 concentric, often very thick deposits, which constrict the 

 afferent and efferent vessels, thus inducing atrophy of the 

 glomerulus and very essentially and prejudicially affecting the 

 secretion of urine. In other cases the increase of the stroma is 

 only apparent and depends upon the atrophy of the secreting 

 elements.] 



§ 190. 



Excretory urinary passages. — The ureters, the pelvis, and 

 calices of the kidney, are all composed of an external fibrous 

 membrane, a smooth muscular layer and a mucous membrane. 



The first, formed of common con- 

 nective tissue and elastic fibres, 

 chiefly of the finer kind, is con- 

 tinuous, at the point where the 

 calices surround the papilla, with 

 the fibrous tunic of the kidney. 

 The muscular layer in the ureters 

 is very distinct, with external, lon- 

 gitudinal and internal transverse 

 fibres, to which, towards the blad- 

 der, internal longitudinal fibres 

 also are superadded. In the pel- 

 vis of the kidney the two mus- 

 cular layers are quite as thick as 

 in the ureter, whilst in the calices 

 they become thinner and thinner, 

 ceasing where the latter are in- 

 serted into the papilla. The mucous membrane of all these 



Fig. 251. Epithelium of the pelvis of the Human kidney, x 350 diam.: A, isolated 

 cells ; B, the same in situ : a, small ; b, large tasselated cells ; c, the same with 

 nucleated corpuscles in the interior ; d 7 cylindrical and conical cells from the deeper 

 layers ; e, transitional forms. 



