The structure and health care knowledge of male reproductive organs

The male reproductive organs are divided into two parts: the external genitalia, including the penis and scrotum; and the internal genitalia, composed of gonads, reproductive ducts, and accessory glands. The gonads are the testes. The reproductive ducts include the epididymis, vas deferens, ejaculatory ducts, and urethra. Accessory glands include the seminal vesicles, prostate gland, bulbourethral glands, urethra, and bladder.

(I) External Genitalia

1. Penis

The penis is composed of three erect, long, cylindrical corpora cavernosa. A pair of corpora cavernosa are arranged parallel to each other on the dorsal side of the corpus spongiosum, through which the urethra passes. The erectile tissue is formed by an irregular network of cavernous sinuses, with arteries and veins communicating with these sinuses. The distal end of the corpus spongiosum expands to form the glans penis. Each cylindrical corpus cavernosum is covered by dense fibrous tissue. The three corpora cavernosa are surrounded by a protofascia called the capsule. At the base of the penis, the posterior ends of the corpora cavernosa separate to form the crura of the corpora cavernosa, which are firmly attached to the pubic bone and the inferior ischial ramus (pubic arch). The penis is supplied with blood from the terminal branches of the internal pudendal artery—the dorsal penile artery.

Erection is the result of blood engorgement of the corpora cavernosa. When the penis is flaccid, the vascular sinuses in the erectile tissue are relatively empty. As the arteries dilate, blood flows into the sinuses of the cavernous tissue, increasing hydraulic pressure and causing the penis to swell and harden. When the rate of arterial blood inflow equals the rate of venous blood return, a balance is reached, and the erection is maintained. The role of venous closure during erection is uncertain. If venous outflow exceeds arterial inflow, the erection subsides, and the penis returns to a resting state.

The blood vessels that produce erection are controlled by nerve impulses. It is speculated that erection is innervated by parasympathetic nerve fibers in the sacral spinal cord, but this remains a controversial issue.

The skin covering the penis is freely movable, and at the glans penis, the skin folds into a double layer of foreskin. Infections or inflammation of the foreskin or glans penis can cause painful intercourse.

Regarding penis size: Many men are very concerned about the size of their penis. They believe that penile development represents a man's masculinity, and a small penis does not demonstrate masculinity. They also worry that it will affect their sex life and fertility after marriage. Therefore, even if their penis is normal or slightly smaller than normal, or their length is within the normal range, they may still consider it a small penis. Consequently, they may be afraid to go to public baths, public toilets, or swimming. Some may even be constantly worried, have no appetite, sleep poorly, lose interest in studying, and feel that life has no meaning. Therefore, it is important to have a correct understanding of penis size and its consequences.