Male Reproductive System
This page outlines the basic anatomy and function of the male
reproductive system. Separate pages describe the
female reproductive system and characteristics of the
reproductive system common to both males and
- Anatomy of the male reproductive system:
- The external genitalia of the male consist of the penis
- The urethra is the common passageway for semen and urine.
- The testes are the male gonads. Sperm travel from the
testes to the urethra via the ductus deferens.
- Accessory glands contribute secretions to the sperm as they
travel along the pathway from the testes to the urethra. These glands
include the prostate gland, the seminal vesicles, and the bulbourethral glands.
Their secretions constitute most of the volume of the semen that the male
- Sperm production takes place within the testes:
- The internal structure of the testes consists of coiled
masses of seminiferous tubules. Germ cells (spermatogonia) embedded in the
walls of the tubules give rise to developing sperm by the process of
meiosis. The primary spermatocyte arises when the spermatogonium commits itself to undergo meiosis via DNA replication. The first division of meiosis then converts the primary spermatocyte into a secondary spermatocyte. The second meiotic division converts the secondary spermatocyte into 2 mobile spermatids, losing most of its cytosol and developing an elongated flagellum.
- Spermatid development is regulated and supported by
Sertoli cells that are also embedded in the walls of the seminiferous
tubules. FSH from the anterior pituitary stimulates the Sertoli cells
to produce a variety of factors required for normal spermatogenesis.
- Androgen binding protein, which traps testosterone in
the fluid surrounding the developing spermatids.
- Inhibin, which selectively inhibits FSH release by
the anterior pituitary.
- The other major function of the testes is production of
testosterone. This is handled by Leydig cells found in the
interstitialspaces (outside the seminiferous tubules). Leydig
cells are stimulated to produce testosterone by LH from the anterior pituitary.
Testerone, in turn, travels back to the anterior pituitary to suppress release
Female reproductive system