Spermatocytogenesis

Schematic diagram of Spermatocytogenesis

Spermatocytogenesis is the male form of gametocytogenesis and involves stem cells dividing to replace themselves and to produce a population of cells destined to become mature sperm.

The stem cells involved are called spermatogonia and are a specific type of stem cell known as gametogonia.

Three functionally separate spermatogonial cell types are recognised on the basis of the appearance of the nuclei: type A dark spermatogonia (Ad), type A pale spermatogonia (Ap), and type B spermatogonia (B).

Type Ad spermatogonia ("dark")

The population of spermatogonia is maintained by type Ad spermatogonia. These cells do not directly participate in producing sperm, instead serving to maintain the supply of stem cells for spermatogenesis.

Each type Ad spermatogonium divides to produce another type Ad spermatogonium, which can further carry on spermatogenesis, and one type Ap spermatogonium, which differentiates further.^[1]

Type Ap spermatogonia ("pale")

Type Ap spermatogonia repeatedly divide mitotically to produce identical cell clones linked by cytoplasmic bridges.

The connections between cells allow development to be synchronised. When repeated division ceases, the cells differentiate into type B spermatogonia. This stage is referred to as the spermatogonial phase.

Type B spermatogonia

Type B spermatogonia undergo mitosis to produce diploid intermediate cells called primary spermatocytes.

References

↑ CLERMONT, Yves (March 1966). "Renewal of spermatogonia in man". American Journal of Anatomy 118 (2): 509–524. doi:10.1002/aja.1001180211. |accessdate= requires |url= (help)

Testes	layers Tunica vaginalis Tunica albuginea Tunica vasculosa Appendix Mediastinum Lobules Septa Leydig cell Sertoli cell Blood–testis barrier

Spermatogenesis	Spermatogonium Spermatocytogenesis Spermatocyte Spermatidogenesis Spermatid Spermiogenesis Spermatozoon

Other	Seminiferous tubules Tubuli seminiferi recti Rete testis Efferent ducts Epididymis Appendix Stereocilia Paradidymis Spermatic cord Vas deferens Ampulla Ejaculatory duct

Accessory glands

External

Penis	root Crus Bulb Fundiform ligament Suspensory ligament body Corpus cavernosum Corpus spongiosum glans Foreskin Frenulum Corona fascia superficial deep Tunica albuginea Septum of the penis

Urinary tract	Internal urethral orifice Urethra Prostatic Intermediate Spongy Navicular fossa External urethral orifice Lacunae of Morgagni Urethral gland

Scrotum	layers skin Dartos External spermatic fascia Cremaster Cremasteric fascia Internal spermatic fascia Perineal raphe Scrotal septum

Index of reproductive medicine

Description	Anatomy male female Physiology menstrual cycle Development sex determination and differentiation

Disease	Infections STD and STI Congenital male female Neoplasms and cancer male female gonadal germ cell Other male female Symptoms and signs eponymous

Treatment	Procedures male female Drugs benign prostatic hypertrophy erectile dysfunction and premature ejaculation sexual dysfunction infection STDs hormones androgens estrogens progestogens GnRH prolactin Assisted reproduction Birth control hormonal

Spermatocytogenesis

Type Ad spermatogonia ("dark")

Type Ap spermatogonia ("pale")

Type B spermatogonia

References

See also