Quantitative ultrastructural analysis of the principal cells in the human epididymis

A morphometric study of the principal epithelial cells of the epididymis has been carried out in six young adult men. Samples were taken in the head, body and tail of the epididymis and processed for ultrastructural study. The cytoplasm was subdivided into four zones. Their section areas were measured by planimetry and the volume density of cytoplasmic organelles assessed using the point-counting method. The general organization of the principal cells of the epididymis was identical along the duct. Quantitative analysis revealed that cells of the head contained significantly larger amounts of coated-vesicles and of Golgi saccules than the body and the tail. The functional implications of these results is important for the understanding of receptor-mediated endocytosis and protein synthesis in the different parts of the human epididymal duct.