A seminiferous tubule is a coiled epithelial tube within the testis in which germ cells develop through spermatogenesis, supported by Sertoli cells. Developing germ cells occupy different positions within the epithelium, and released sperm enter the lumen. Leydig cells lie outside the tubules in the intervening tissue.[ref]
Anatomy and Physiology 2e by J. Gordon Betts and others. Section27.1: seminiferous-tubule organization and spermatogenesis
Specialized contacts between neighboring Sertoli cells contribute to the blood-testis barrier, helping organize the local environment of the developing germ cells. The wall is therefore an active cellular interface, rather than simply a pipe through which mature sperm flow.
A useful histology exercise compares a section with a three-dimensional reconstruction. Several circular profiles can be different cuts through one coiled seminiferous tubule; counting profiles does not directly count independent tubes. Likewise, preservation of a recognizable tubular outline does not establish normal germ-cell development. In a 2014 mouse experiment, removing Sertoli cells caused extensive germ-cell loss while much of the tubular framework remained identifiable.[ref]
Sertoli cells maintain Leydig cell number and peritubular myoid cell activity in the adult mouse testis by Diane Rebourcet and others. Results,Figure2: germ-cell loss and retained tubular architecture
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