ACCESSORY GLANDS
Semen is the fluid that provides a transport medium for the sperm. Semen also contains nutrients and a pH buffer that keeps sperm alive. The paired seminal vesicles, located behind the urinary bladder, secrete into the vasa deferentia a portion of the semen that contains fructose and prostaglandins. The single prostate gland, located beneath the bladder, secretes an alkaline portion of semen into the ejaculatory duct (which connects the vasa deferentia to the urethra). This alkaline fluid may neutralize any acidity in the male urethra and in the female vagina. The final set of accessory glands are the bulbourethral glands, located on either side of the beginning of the urethra. These glands release a mucous secretion.