What is the structure and function of male genitalia?

Male genitalia is divided into internal genitalia and external genitalia. Male internal genitalia includes testis, vas deferens and accessory glands. Testis is a gonad that produces male germ cells (sperm) and secretes male hormones; The vas deferens is a conduit for transporting sperm and expelling it from the body, including epididymis, vas deferens and ejaculatory duct. The accessory glands are seminal vesicle and prostate. Their secretions and sperm together form semen, which has the function of nourishing and promoting sperm vitality. Male external genitalia includes penis and scrotum.