Human Reproduction

The microscopic structure of the testis is described in NCERT Class 12, Chapter 3 (Human Reproduction), where each seminiferous tubule is lined by two cell types: the dividing male germ cells and the large Sertoli cells. Sertoli cells, also called nurse cells, extend from the basement membrane toward the lumen and provide nutrients and mechanical support to the developing spermatids during spermatogenesis. Leydig cells are incorrect because they lie outside the tubules in the interstitial tissue and secrete androgens such as testosterone rather than nourishing germ cells. Spermatogonia are the undifferentiated germ cells that divide to begin sperm formation and are themselves the cells being supported, not the supporters. Primary spermatocytes are an intermediate meiotic stage of the germ cell line and likewise require nourishment rather than providing it. A structural consistency check confirms the answer: the cells that physically embrace and feed the maturing sperm inside the tubule are the Sertoli cells, exactly as the question specifies.