Contractile cells in human seminiferous tubules.

Electron microscopic study of the peritubular connective tissue in human testis reveals the presence of "contractile-type" cells rather than of typical fibrocytes. Their cytoplasm has numerous fine filaments and other components. characteristic of smooth muscle cells. The rough-surfaced endoplasmic reticulum, however, is relatively prominent In some instances, the nuclear surface appears scalloped or folded, and the cell surface presents an irregular profile, similar to that of contracted cells.