The male reproductive system makes sperm and testosterone and carries sperm out of the body. Much of it sits outside the pelvis, so a lot of it can be examined by hand.
Testes and scrotum
The testes make sperm in coiled seminiferous tubules and make testosterone in the cells between those tubules. The scrotum keeps them a few degrees cooler than the body core, which sperm production needs.
Epididymis and vas deferens
Sperm mature in the epididymis, a comma-shaped tube on the back of each testis. The vas deferens carries them up through the inguinal canal into the pelvis.
Accessory glands
The seminal vesicles and the prostate add most of the fluid in semen. The prostate wraps around the urethra just below the bladder, so an enlarged prostate can block urine flow.
Penis and urethra
The urethra carries both urine and semen. An erection happens when spongy erectile tissue fills with blood under the control of nerves and blood vessels.
| Structure | Main job | What you feel or see |
|---|---|---|
| Testis | Makes sperm and testosterone | Smooth, firm, oval, about 4 to 5 cm long |
| Epididymis | Stores and matures sperm | Soft ridge on the back of the testis |
| Vas deferens | Carries sperm toward the urethra | Firm cord inside the spermatic cord |
| Prostate | Adds fluid to semen | Felt on rectal exam, rubbery, with a central groove |
At the bedside
A painful, high-riding testis with a lost cremasteric reflex suggests testicular torsion, a surgical emergency. A hard, painless lump in the testis needs an urgent ultrasound to rule out cancer.
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Written by Making Synapses. Topic reference: OpenStax, Anatomy and Physiology 2e (no text adapted).