Male Reproductive System
Learning objectives
- Understand and identify the components of the male reproductive system and the associated glands.
- Understand and identify the stages in spermatogenesis and the cells that play essential roles in these processes.
- Be aware of the importance of the blood-testis barrier.
The male reproductive system consists of the testes, the excretory ducts and associated glands, the penis, and the scrotum. The testes contain many seminiferous tubules, which are lined by a germinal epithelium consisting of germinal elements (spermatogonia, spermatocytes, and spermatids) and Sertoli cells. Lying between the seminiferous tubules are the interstitial cells of Leydig, which produce the male sex hormones (androgens). When sperm leave the seminiferous tubules they pass through the following series of ducts:
| Ducts | Characteristics |
| 1. tubuli recti | short, straight tubules lined by cuboidal or columnar epithelium (Sertoli cells); site of fluid secretion. |
| 2. rete testis | labyrinth of anastomosing channels in the mediastinum lined by cuboidal or low columnar epithelium, each cell of which has a single cilium; site of fluid secretion. |
| 3. efferent ducts | pseudostratified epithelium with alternating patches of ciliated columnar and cuboidal cells; major site of fluid resorption; smooth muscle in wall of ducts. |
| 4. ductus epididymis | long coiled duct with thin smooth muscle coat and a pseudostratified epithelium; columnar cells (called principal cells) which bear non-motile processes known as stereocilia are interspersed with rounded basal cells (found near the basement membrane); site of fluid absorption and sperm storage and maturation. |
| 5. ductus deferens | thick muscular wall (to move spermatozoa toward ampulla) lined by pseudostratified columnar epithelium with some stereocilia. |
| 6. ampulla | dilated portion of ductus deferens. |
| 7. ejaculatory duct | narrower than ampulla; runs through prostate gland to empty into urethra. |
The male sex accessory glands are the paired seminal vesicles, the prostate gland, and the paired bulbourethral glands. The duct of each seminal vesicle unites with the ampulla of a ductus deferens to form a common ejaculatory duct. The prostate gland surrounds the ejaculatory duct and the prostatic urethra, and secretes into the latter.