Attribute: Henry Vandyke Carter [Public domain], via Wikimedia Commons
The glands that make semen are the seminal vesicles as it contribute nutrients and fluid to semen. The seminal vesicles (a pair) along with prostate gland and bulbourethral glands (Cowper glands) provide a fluid medium for the sperm.
Seminal vesicles help nourish the sperm; secretes fructose (carbohydrate; provides the sperm the source of energy) and most of the seminal fluid. Secrete analkaline, fructose-rich fluid. Prostaglandins are also released by the seminal vesicles which represent about 60% of the volume of semen.
Seminal vesicle is attached to the vas deferens and lie at the base of the urinary bladder in males.