Semen is a mixture of sperm and seminal fluid, a liquid that consists of the secretions of the seminiferous tubules, seminal vesicles, prostate, and bulbourethral glands.
The seminal fluid (which is primarily composed of water, fructose, proteins, minerals, and other micronutrients) provides the sperm with a transportation medium, nutrients, and protection from the hostile acidic environment of the male’s urethra and the female’s vagina.