Cell Junctions in the Seminiferous Tubule and the Excurrent Duct of the Testis: Freeze-Fracture Studies

Publisher Summary This chapter describes the morphological observations of intercellular junctions in the seminiferous tubule and the excurrent duct system of mammalian testes as revealed by freeze fracturing. The junctions in the nonmammalian testes are also described. The seminiferous epithelium resting on the seminiferous tubule consists of two cellular populations: spermatogenic cells and Sertoli cells. These originate from different germinal layers during histogenesis. All generations of the clonal spermatogenic cells are connected with each other by the cytoplasmic bridges to form syncytia until spermiation. The Sertoli cells or supporting cells never divide in the adult testis and are separated by their cell membranes as individual cells. Intercellular junctions among the epithelial lining cells other than the Sertoli cells are recognized as the terminal bar by light microscopy. The junctional complexes of the epithelial cells lining the excurrent duct system are situated in the juxtaluminal area of the cell. More comparative, experimental, and clinicopathological studies on the junctional complexes would be necessary to understand the blood–testis barrier and the environments of the excurrent duct system.