The male reproductive system mainly consists of two parts: the external genital organs and the internal genital organs. The external genital organs mainly include the penis and the scrotum, which is mainly used for urination, sexual intercourse and ejaculation, and is the main organ of male sexual behavior; while the scrotum is located under the penis in the form of a skin pouch, which shrinks when the external temperature decreases, and stretches when the external temperature rises. Among the internal genital organs, the testes are located in the scrotum in an ovoid shape and mainly produce sperm; the epididymis promotes the development and maturation of sperm, as well as the transportation and storage of sperm; the vas deferens and ejaculatory ducts have strong peristalsis, which can discharge and transport sperm; the seminal vesicles are involved in the process of sexual activity and ejaculation; and the secretion of the prostate gland is conducive to the dilution of seminal fluid and the activities of spermatozoa.