The primary function of the urethra is to expel urine from the urinary bladder to the outside of the body. In males, the urethra also serves as a passage for semen during ejaculation. The uterus, on the other hand, is a sac-like organ in the female reproductive system that nourishes and protects the developing fetus during pregnancy.

Urethra:
A tube that carries urine from the bladder to the outside of the body.
In males, it also transports semen during ejaculation.
Part of the urinary and reproductive systems.
Uterus:
A muscular organ where the fetus develops during pregnancy.
The lining of the uterus thickens monthly in preparation for potential pregnancy.
Part of the female reproductive system.