Seminal vesicles are a pair of simple tubular glands that are located posterior-inferior to the urinary bladder of males. They are also called seminal glands. Their secretion is a constituent of the semen produced by the males. Around 70-75% of the semen is composed of secretions of the seminal vesicles which includes proteins, enzymes, fructose, mucus, vitamin C, flavins, phosphorylcholine, and prostaglandins. Their excretory ducts open into the vas deferens. Their structure and function are mainly controlled by androgens.