The seminal vesicles develop as one of three structures of the male reproductive system that develops at the junction between the urethra and vas deferens. The vas deferens is derived from the mesonephric duct, a structure that develops from mesoderm.
Function:
The seminal deferens produce a sugar-rich fluid (fructose) that provides sperm with a source of energy to help them move. The fluid of the seminal vesicles makes up most of the volume of a man's ejaculatory fluid, or ejaculate.