Page 714 - Atlas of Histology with Functional Correlations

FIGURE 18.7 ■ Ultrastructure of cells in the proximal convoluted tubule of the

kidney. Courtesy of Dr. Rex A. Hess, Professor Emeritus, Comparative
Biosciences, College of Veterinary Medicine, University of Illinois, Urbana, IL.
×55,000.

FIGURE 18.8 | Ultrastructure of Apical Cell

Surface in Proximal Convoluted Tubule of Kidney

This high-power ultrastructure image shows the apical cell surface of the
proximal convoluted tubules of the kidney. The long and closely packed
microvilli (1, 6) of the brush border extend into the lumen. In the cytoplasm are
also clear pinocytotic vesicles (2, 7). A tight junctional complex (3) is visible

as a dark strip near the base of the microvilli or the apical region of the cell.
However, individual cell boundaries in the proximal tubules are not seen because
of the complex interdigitations of the lateral cell walls. Also visible in the apical
cytoplasm are numerous dense-staining lysosomes (4, 8), which will break down

the substances that are brought into the cytoplasm by the pinocytotic vesicles (2,
7). The apical cytoplasm also exhibits numerous mitochondria (5) and a section
of the nucleus (9).

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