spermatids have half the number of chromosomes as the original cell. However, they are still
immature and cannot move on their own.
The spermatids are transferred from the testes to the epididymis. In the epididymis, they
gradually become mature. They grow a tail. They also lose some of the cytoplasm from
the head. Once they mature, they are able to “swim.” The mature sperm are stored in
the epididymis until it is time for them to leave the body. To watch an animation of all
these steps of sperm production, visithttp://www.pennhealth.com/health_info/anima-
tionplayer/sperm_production.html
Sperm leave the epididymis through the vas deferens (Figure22.1). As they travel through
the vas deferens, they pass by the prostate and other glands. The sperm mix with fluids
from these glands, forming semen. The semen travels through the urethra and leaves the
body through the penis. A teaspoon of semen may contain as many as 500 million sperm!
Lesson Summary
- The main functions of the male reproductive system are to produce sperm and secrete
testosterone. - Male reproductive organs include the penis, testes, and epididymis.
- Sperm are male gametes that form in the testes and mature in the epididymis.
Review Questions
Knowledge and Comprehension
- What are sperm?
- What is the main sex hormone in males?
- Which organs produce sperm and secrete testosterone?
- What is the function of the tail of a sperm?
- Arrange the following structures in the order that sperm pass through them: urethra,
epididymis, vas deferens. - Explain what testosterone does in males.
- Contrast the roles of the testes and penis in reproduction.
- How do sperm differ from semen? How are the two related?
- Explain why sperm production is not completed when spermatids have been produced.
- Why is the epididymis needed for reproduction in males?
Further Reading / Supplemental Links
CK–12.org, High School Biology, Chapter 40, Lesson 1.