: a firm partly muscular partly glandular body that is situated about the base of the mammalian male urethra and secretes an alkaline viscid fluid which is a major constituent of the ejaculatory fluid—called also prostate
Chestnut-shaped male reproductive organ, located under the bladder, which adds secretions to the sperm during ejaculation of semen. It surrounds the urethra (seeurinary system) and is rounded at the top, narrowing to a blunt point. The prostate consists of 30–50 glands, supported by connective tissue, that discharge fluids into the urethra and two ejaculatory ducts. Those ducts, which also carry sperm and fluid discharged by the seminal vesicles, join the urethra inside the prostate. The prostate contributes 15–30% of the seminal fluid. It reaches its mature size at puberty. Around age 50, it commonly shrinks and decreases its secretions; an increase in size after midlife may be due to inflammation or malignancy. See alsoprostatic disorder.