A person does not require a functioning prostate to live, but it is important for fertility. The following sections discuss the functions of the prostate.
Helping to produce semenThe primary function of the prostate is to contribute prostatic fluid to semen. The prostate contributes 20–30% of fluid to the total semen volume. The remainder comes from the seminal vesicles (50–65%) and the testicles (5%).
Prostatic fluid contains components that make semen an ideal substance for sperm cells to live in, including enzymes, zinc, and citric acid. One important enzyme is prostate-specific antigen (PSA), which helps make the semen thinner and more fluid.
The fluid in semen helps the sperm trel down the urethra and survive the journey towards an egg, which is essential for reproduction.
Prostatic fluid is slightly acidic, but other components of semen make it alkaline overall. This is to counteract the acidity of the vagina and protect the sperm from damage.
Closing the urethra during ejaculationDuring ejaculation, the prostate contracts and squirts prostatic fluid into the urethra. Here, it mixes with sperm cells and fluid from the seminal vesicles to create semen, which the body then expels.
When the prostate contracts during ejaculation, it closes off the opening between the bladder and urethra, pushing semen through at speed. This is why, in typical anatomic situations, it is impossible to urinate and ejaculate simultaneously.
Hormone metabolismThe prostate needs androgens, which are male sex hormones, such as testosterone, to function correctly.
The prostate contains an enzyme called 5-alpha reductase, which converts testosterone into a biologically active form called dihydrotestosterone (DHT).
This hormone is important for normal prostate development and function. In the developing male, it is crucial for the development of secondary sex characteristics, such as facial hair.