The male reproductive system produces sperm cells, delivers them through a set of ducts, and makes hormones that support sexual development and fertility. Its organs include external structures such as the penis and scrotum, as well as internal structures such as the testes, epididymis, vas deferens, seminal vesicles, and prostate gland. Understanding this system helps explain how reproduction occurs and how hormones influence body development.
It also connects anatomy with cell biology because sperm formation depends on meiosis and specialized cell maturation.
Sperm are produced in the seminiferous tubules of the testes, then mature and are stored in the epididymis. During ejaculation, sperm travel through the vas deferens and mix with fluids from the seminal vesicles, prostate gland, and bulbourethral glands to form semen. Hormones from the brain and testes regulate this process through feedback loops involving the hypothalamus, pituitary gland, and testosterone.
Temperature control is also important because the scrotum helps keep the testes slightly cooler than core body temperature for normal sperm production.
Key Facts
- Sperm are produced in the seminiferous tubules of the testes by spermatogenesis.
- Spermatogenesis includes meiosis, so each sperm cell has 23 chromosomes in humans.
- Sperm path: seminiferous tubules to epididymis to vas deferens to ejaculatory duct to urethra.
- Semen = sperm cells + glandular fluids from the seminal vesicles, prostate gland, and bulbourethral glands.
- The hypothalamus releases GnRH, which stimulates the pituitary to release FSH and LH.
- LH stimulates testosterone production, and FSH supports sperm production in the testes.
Vocabulary
- Testes
- The paired male gonads that produce sperm and the hormone testosterone.
- Epididymis
- A coiled tube on each testis where sperm mature and are stored before transport.
- Vas deferens
- A muscular duct that carries sperm from the epididymis toward the ejaculatory duct.
- Seminal vesicles
- Glands that add fructose-rich fluid to semen to help nourish sperm.
- Prostate gland
- A gland below the bladder that adds fluid to semen and helps activate sperm movement.
Common Mistakes to Avoid
- Calling semen and sperm the same thing is wrong because sperm are the cells, while semen is the mixture of sperm and fluids from several glands.
- Thinking sperm are made in the prostate gland is wrong because sperm are produced in the seminiferous tubules of the testes.
- Skipping the epididymis in the sperm pathway is wrong because sperm must mature there before they can move effectively.
- Assuming testosterone is made by the pituitary gland is wrong because the pituitary releases LH, which stimulates testosterone production in the testes.
Practice Questions
- 1 A sperm cell starts in a seminiferous tubule. List the major structures it passes through before leaving the body through the urethra.
- 2 In humans, a body cell has 46 chromosomes. How many chromosomes should each sperm cell have after meiosis, and why?
- 3 Explain why the scrotum holds the testes outside the main body cavity and how this relates to spermatogenesis.