Primordial germ ell in embryo Differentiation Epididymis Spermatogonium Mitotic division producing large numbers Differentiation and onset of meiosis I Testis Seminiferous tubule Primary spermatocyte section of / . in prophase of meiosis I Meiosis I completed Secondary spermatocyte Meiosis lI Sertoli @@@@ Spermatids spermatids (at two stages of\ differentiation) Differentiation ertoli cells provide nutrients) rm cells oza seminiferous tubule Copyright o Pearson Education, Inc, publishing as Benjamin Cummings 精子生成 上一页下一页精子生成 上一页 下一页