prostate /pros″tāt/ [Gk, prostates, standing before] , a gland in men that surrounds the neck of the bladder and the proximal part of the urethra and produces a fluid that becomes part of semen. A firm structure normally about the size of a chestnut, the prostate is located in the pelvic cavity, below the inferior part of the symphysis pubis and ventral to the rectum, through which it can be felt, especially when it is enlarged. A depression on its cranial border accommodates the entry of the two ejaculatory ducts from the seminal vesicles. The prostate is composed of glandular and muscular tissue and contracts during ejaculation of seminal fluid. The prostatic secretion contains alkaline phosphatase, citric acid, prostate-specific antigen, and various proteolytic enzymes. −prostatic, adj.
