What is the Prostate?

The prostate is one of the male sex glands. The prostate adds nutrients and fluid to the sperm. During ejaculation, the prostate secretes fluid that is part of the semen. The other major sex glands in men are the testes and the seminal vesicles. Together, these glands store and secrete the fluids that make up semen.

The prostate is about the size of a walnut and can be divided into two parts referred to as the right or left lobes. It lies just below the urinary bladder and surrounds the upper part of the urethra. The urethra is the tube that carries urine from the bladder and semen from the sex glands out through the penis. As one of a man’s sex glands, the prostate is affected by male sex hormones. These hormones stimulate the activity of the prostate and the replacement of prostate cells as they wear out. The chief male hormone is testosterone, which is produced almost entirely by the testes.