What is the function of the urethra in male vertebrates?

The urethra in male vertebrates has the primary function of conveying semen outside the body during ejaculation. In male anatomy, the urethra serves a dual purpose; it is the final part of the reproductive tract and also part of the urinary system. During sexual activity, the urethra transports sperm from the reproductive organs out through the penis, facilitating reproduction.

In addition to its role in reproduction, the urethra does also conduct urine, but this function is secondary in terms of the question posed. It does not convey nutrients to the kidneys, as that role is performed by blood through renal arteries. Additionally, the urethra has no role in conveying air to the lungs, which is the function of the respiratory system, specifically the trachea and bronchi. Thus, the function of the urethra is distinctly associated with the passage of semen in males, distinguishing it from the other functions listed.