Spermatogenesis
Spermatogenesis is the process by which haploid spermatozoa develop from the diploid spermatogonial germ cells in the seminiferous tubules of the testicle.
This process starts with the mitotic division of the spermatogonial germ cells located close to the basement membrane of the tubules
The mitotic division of these produces two types of cells.
Type A cells replenish the stem cells.
Type B cells differentiate into primary spermatocytes.
Primary spermatocytes are the largest spermatogenic cells and are usually abundant at all levels between the basement membrane and the lumen.
Each divides to form two secondary spermatocytes, which are rarely seen because they undergo the second meiotic division almost immediately to form two haploid spermatids. Newly formed round, early spermatids (ES) differentiate and lose volume in becoming late spermatids (LS) and finally highly specialized sperm cells. All stages of spermatogenesis and spermiogenesis occur with the cells intimately associated with the surfaces of adjacent Sertoli cells (SC) that perform several supportive functions. Both X750. H&E.