Cytological Studies on the Renal Corpuscle and the Proximal Convolution of the Renal Tubules in the Human Kidney

Part 2 Cytological Observations on the Cellular Elements of the Glomerulus in the Human Kidney

Abstract

In the present cytological and histological research, the normal glomeruli in fresh human kidneys from five healthy executed men were studied with special reference to cytological characteristics of the cellular elements of the glomeruli as well as histogenetical relationship between the surfacing cells (Deckzellen) of the glomerulus and the epithelial cells of the Bowman's capsule.
In the cytoplasm of the surfacing cells of the glomerulus a well developed net-like Golgi apparatus, a number of slender rod-shaped mitochondria, stainable granules and vacuoles are demonstrated, which facts suggest that these cells are provided with a secretory activity, sending secretory material into the cavity of the Bowman's capsule.
Among such ordinary (typical) surfacing cells, there occur in indefinite parts of the glomerulus variable number of peculiar surfacing cells with darker cytoplasm containing more numerous thicker mitochondria, numerous coarse stainable granules and vacuoles. On the basis of these cytological evidences it may be concluded that these atypical surfacing cells would play more active secretory function than the ordinary ones. It must be one of the noteworthy findings obtained in the present study that these atypical surfacing cells of the glomerulus are apparently identical with the atypical epithelial cells often found in the epithelium of the Bowman's capsule. In the author's previous study on the epithelial cells of the proximal convolution of the renal tobulus it was learned that these atypical epithelial cells of the Bowman's capsule epithelium are identical with the epithelial cells of the proximal convolution. All of these findings in both the present and the preceding investigations support the view that the lining cell layers of the three parts of the nephron are continuous and of the same origin, namely of epithelial nature. In the present study the author could actually confirm the continuity of the Bowman's capsule epithelium and the surfacing cell layer of the glomerulus.
Therefore it appears appropriate to designate the surfacing cells (Dec kzellen) of the glomerulus as“ visceral epithelial cells of the Bow ma n's capsule” against the conventional term, parietal epithelial cells of the Bowman's capsule.