Semen consists of 10% sperm and 90% fluid. As sperm pass down the ducts from the testes to the penis the accessory gland add various secretions.
The prostate gland and seminal vesicles secrete fluids that maintain the mobility and viability of the sperm.
Seminal vesicles secrete a fructose rich liquid, which provides energy for the mobility of the sperm
it also contains hormone-like compounds (prostaglandins) which stimulate contractions of female reproductive tract
Prostate gland secretes a thin lubricating liquid containing enzymes which regulate semen viscosity
