Prostate gland
The prostate gland is a small walnut sized gland that encircles the first part of the urethra which moves urine from the bladder along the penis. A thick white fluid is produced by the prostate and this fluid combines with the sperm from the testicles to form semen. The semen is turned into liquid by a protein called prostate-specific antigen (PSA) which is produced by the prostrate.