The rete testis in man: Ultrastructural aspects

Summary The ultrastructure of the normal human rete testis was analyzed. The rete testis cavities are irregularly shaped and contain virtually no spermatozoa. Smooth muscle cells often surround the cavities.In the epithelial lining, two cell types are distinguishable. Flat, dark cells exhibit numerous slender microvilli, and numerous apical and basal microvesicles. Prismatic, lighter cells have more cell organelles, mostly polarized towards a supranuclear position. Both cell types contain variable amounts of glycogen and fat, and an occasional cilium. All cells display intricate lateral cell surfaces that possess different cell-to-cell attachment devices. Intermediate cell types are frequently found.On a morphological basis, the epithelial cells seem to be involved in the release of substances into the lumen and probably also in transport towards the base.Connective tissue elements are found subjacent to the epithelium. Scattered among the fibrocytes are typical smooth muscle cells. Expansions of some smooth muscle cells are connected to the epithelial basement membrane by a network of microfibrillar material. The smooth muscle cells may be involved in changing the shape of the rete testis channels, thus promoting the flux of the rete testis fluid.Different types of nerve fibre bundles are distinguished in the connective tissue of the rete testis which may correspond to autonomic and sensory nerves or sensory receptors.Presented in part at the 31st Annual Meeting of the American Fertility Society, Los Angeles, April 1975Fellow of the Alexander von Humboldt Stiftung, on leave of absence from Depto. de Biologia Celular y Genética Sede Norte, Universidad de Chile, Santiago. Supported by travel aid from the Hamburgische Wissenschaftliche StiftungSupported by Grants from the Deutsche ForschungsgemeinschaftDedicated to Prof. Dr. Drs. h.c. Wolfgang Bargmann on the occasion of his 70th birthday