Male reproductive organs

The human urinary system plays a fundamental role in the normal life activities of the human body, the reproduction and development trend of the human population. The human reproductive function is controlled by the central nervous system and blood growth hormones, and is maintained by the various life activities of the reproductive organs of both sexes, including the production of somatic cells, fertilization, "embryo implantation" of sperm and egg combination, the growth and development of test tube embryos, and the whole process of pregnancy, childbirth, and growth and development.

The external structures of the male reproductive and urinary system include: male genitals, scrotum, male testicles; the internal structures include: ejaculatory duct, urethral opening, male prostate and seminal vesicles.

The testicles produce sperm with male genes and store them in the seminal vesicles. During sexual intercourse, sperm are ejected through the ejaculatory duct and erect penis.

The male genitals are composed of the root, body and head (glans penis). The root is close to the abdomen, the middle part is the body of the male genitals, and the tail end is the glans penis, which is cone-shaped. The urethra is the passage for urine and semen to be discharged, and it opens at the front of the glans penis. The bottom of the glans penis is called the coronal sulcus. For men who have not undergone circumcision, the foreskin is too long to widen from the coronal sulcus of the male genitals to cover the entire glans penis.

The penis is made up of three long columns with spaces (sinuses) that can become hard. Two large corpora cavernosa are arranged parallel to each other between the penis bones. The other is the corpora cavernosa, which surrounds the urethral opening. When the spaces in the corpora cavernosa are filled with blood, the penis becomes hard and becomes thicker and harder.

The scrotum is a thin skin sac that surrounds and protects the testicles. The scrotum has the function of regulating the temperature of the testicles. Because the testicles need to maintain a temperature slightly lower than the body temperature, sperm can grow and develop normally. When the levator testis muscle on the inner wall of the scrotum is relaxed, the testicles are far away from the body, and the temperature decreases. When the levator testis muscle is contracted, the testicles are close to the body, which increases the temperature and is also protected.

The testicles are located in the scrotum and are oval in shape, about the size of a large olive. The left testicle is usually lower than the right one. The testicles have two functions: producing sperm and producing testosterone (the most important hormone). The epididymal cyst is located above the testicles and is made up of a thin tube about 6 meters long. It collects sperm from the testicles and provides a suitable place and environment for the sperm to thrive.

The ejaculatory duct is a cord-like tube that transports male sperm through the epididymal cyst. The ejaculatory duct on one side starts from the same direction as the male testicle, rises to the back of the male prostate and enters the urethra to form the vas deferens. Other structures, such as blood vessels and nerves, also form a cord-like structure with the ejaculatory duct, which is called the sperm tract.