THE KIDNEY 



433 



The epithelium of the convoluted tubule is of the columnar or pyram- 

 idal type, its cells having broad, firmly united bases and conical free 

 apices. The lateral margins of the cells are often so intimately blended 

 at the base as to resemble a syncytium. When isolated, or if outlined 

 by impregnation with silver salts, the borders of the epithelial cells are 

 extremely irregular and are deeply fluted or serrated, the serrations of 

 each cell interdigitating with those of its neighbors. The deep fluted ser- 



FIG. 404. FROM A LONGITUDINAL SECTION 

 OF A CONVOLUTED TUBULE OF THE 

 GUINEA-PIG'S KIDNEY. 



The cell outlines have been blackened by 

 the Golgi method. Very highly magnified. 

 (After Landauer.) 



FIG. 405. CROSS SECTION OF A 

 PROXIMAL CONVOLUTED TUBULE 

 FROM THE KIDNEY OF A MOUSE, 

 SHOWING BASAL FILAMENTS 

 (PROBABLY LARGELY MITOCHON- 

 DRIAL) BREAKING UP INTO GRAN- 

 ULES CENTRALLY, AND THE CEN- 

 TRAL STRIATED BORDER OF THE 

 CELLS. 



Meves' mitochondrial technic. 

 X 1000. 



rations of the interlocked epithelium gives many of its cells a coarsely 

 striated appearance, the striation being more prominent beneath the 

 centrally situated nucleus than in the apical portion of the cell. Other 

 longitudinal striations in the proximal or basal portion of the cell are 

 the result of a linear arrangement of granules and filaments which occur 

 in this part. These appearances often give the epithelium of the convo- 

 luted tubules a peculiar striated or 'rodded' character. The granules and 

 filaments are probably largely mitochondrial in nature. 



The apices of the epithelial cells are very easily destroyed, but when 



