Each of the male testes is composed of lobules, compartments which contain one to three seminiferous tubules each.
a. within these structures, cells undergo spermatogenesis, the production of sperm.
b. during this process, spermatagonia divide to produce primary (2n) spermatocytes.
c. after these spermatocytes move away from the outer wall and increase in size, they undergo meiosis to produce secondary spermatocytes with 23 chromosomes (n).
d. secondary spermatocytes undergo a second division to produce four spermatids also with 23 chromosomes each.