Spermatogenesis consists of three stages: mitotic proliferation of spermatogonia, meiosis of spermatocytes, and spermiogenesis where spermatids are packaged into sperm. During mitotic proliferation, spermatogonia undergo mitosis and differentiate into primary spermatocytes. Meiosis of the spermatocytes then produces haploid spermatids. Spermiogenesis involves the spermatids developing into mature sperm through resorption of cytoplasm and formation of characteristic sperm structures like the head, midpiece and tail. Hormones like FSH, LH and testosterone regulate and trigger the process of spermatogenesis.

1. GAMETOGENISIS
spermatogenisis

3. SPERMATOGENISIS CONSISTS
▪ MITOTIC PROLIFERATION
▪ MEOSIS
▪ SPERMATOGENISIS PACKAGING

4. TESTES

5. 1. Mitotic Proliferation (Spermatogonia – Primary Spermatocyte)
▪ 3 types of Human Spermatogonia seen in histological sections
▪ Type A dark (Ad) Spermatogonia; Ovoid nucleic, dark-staining
Stem cell.
▪ Type A pale (Ap) Spermatogonia; Ovoid nuclei, lightly/pale
staining.
Committed/progenitor cell
SPEMATOGENISIS STAGES

6. ▪ TYPE B: pushed adluminal - committed for meiosis
 Undergo final mitotic division & produce 2 Primary Spermatocyte (spherical &
euchromatic, pale-stained)
▪ Primary Spermatocyte replicate DNA & enter Meiosis

8. Spermatogenesis: stages
2. Meiosis:
(Spermatocytes to Spermatids)
▪ Primary spermatocyte, soon after their formation, enter meiotic prophase I
▪ Homologous chromosomes separate in the first division – produces smaller
cells called secondary spermatocytes with only 23 chromosomes (22 + X or
22 + Y)(Each still has 2 chromatids )
▪ Division of each secondary spermatocyte separates the chromatids of each
chromosome and produces 2 haploid cells called spermatids
▪ Spermatids later differentiate into sperms

10. Spermatogenesis: stages
3. Spermiogenesis or packaging (Spermatids – Sperms)
▪ Process by which spermatids differentiate into spermatozoa,
which are highly specialized to deliver male DNA to the ovum
▪ A spermatid sheds its superfluous cytoplasmic baggage with
help of Sertoli cells
▪ Resulting sperm has:
HEAD – with nucleus, and acrosome (has hydrolytic enzymes)
Mid Piece – with mitochondria (for energy production)
Tail – flagellum for locomotion

12. The role of hormones & Cells
▪ Spermatogenesis is triggered at puberty by
a surge in GnRH, FSH and LH (as well as
Testerone)
▪ LH further triggers testosterone release by
Leydig cells – required for early spermatid
maturation (late stages require FSH)

13. SPERM
▪ Males don’t run out of sperm because mitosis precedes each
meiosis
▪ 48 days from meiosis I to a mature Sperm, 64 days from
spermatogonium to maturity
▪ Human males produce about 1000 sperm per second (30
billion per year)
▪ Each ejaculation – 300 million sperm (normal count – at least
100 million/ml with average of 3ml of ejaculate)
▪ Counts below 20 million/ml, usually sterile