Epididymis

The epididymis is a highly coiled, tubular structure that plays an important role in sperm maturation, storage and transport. The epididymal ducts are surrounded by concentric layers of fibromuscular tissue rich in smooth muscle cells with blood vessels and nerves in the adjacent supporting stroma. The epithelium of the epididymis consists of tall columnar cells called principal cells and basal cells. Principal cells are the major cell type and have straight stereocilia to facilitate flow of sperm through the epididymis. In addition, the epididymis contains clear cells and mitochondria rich apical cells are present together with few scattered macrophages and lymphocytes.