Transformation of the spermatid into the mature sperm involves reorganisation of the nucleus and cytoplasm, and development of the flagellum (Fig. 11.14). Sperm formation takes approximately seventy days, and transport through the epididymis to the ejaculatory duct requires an additional twelve to twenty-one days. Upon leaving the testes, sperm have a poor capacity to fertilise. During passage through the epididymis, the sperm mature, as evidenced by development of the capacity for sustained motility, modification of the nuclear chromatin and tail organelles, and loss of the cytoplasmic remnant.
