TY - JOUR AU1 - Wrobel, Karl-Heinz AU2 - Sinowatz, Fred AU3 - Mademann, Roswitha AB - The intratesticular excurrent duct system of the bull is composed of rete testis, tubuli recti, and the terminal segment of the seminiferous tubules. Each terminal segment is surrounded by a vascular plexus and may be subdivided into a transitional region, middle portion, and terminal plug. The modified supporting cells of the middle portion and the terminal plug no longer display the typical Sertoli-Sertoli junctions seen in the transitional region and the seminiferous tubule proper. In the region of the terminal plug a distinct central lumen is generally not observed: spermatozoa and tubular fluid must pass through an intricate system of communicating clefts between the apices of the closely attached modified supporting cells. Vacuoles in the supranuclear region of the cells in the middle portion indicate strong transepithelial fluid transport. In analogy to the epithelium of rete testis and tubuli recti, the supporting cells of the terminal segment are capable of phagocytosing spermatozoa. The vascular plexus investing the terminal segment serves a dual purpose: it is a regulatory device for fluid and sperm transport, as well as an area of increased diapedesis for white blood cells. TI - The fine structure of the terminal segment of the bovine seminiferous tubule JF - Cell and Tissue Research DO - 10.1007/BF00216216 DA - 1982-06-01 UR - https://www.deepdyve.com/lp/springer-journals/the-fine-structure-of-the-terminal-segment-of-the-bovine-seminiferous-K0pyw3Fr36 SP - 29 EP - 44 VL - 225 IS - 1 DP - DeepDyve ER -