The age range of adolescence is about 10 ~ 20 years old. But for every child, there are great individual differences in the beginning and maturity of adolescence, which will be influenced by many factors such as race, gender and living environment. Generally speaking, boys enter puberty two years later than girls on average. During this period, every child's body size, shape, physiological function and psychological behavior will change significantly. Among them, the development and function of reproductive system are becoming more and more mature, which is more noticeable. Therefore, adolescence is the transition period from children to adults, and it is the key period to determine a person's life development level.
Why is the development of reproductive system the most prominent? It turns out that in the process of human growth and development, the development of human systems is early or late, fast or slow. From birth to 10 years old, the reproductive system changes very little, and it is almost "inactive" compared with other fast-growing organs. But once puberty begins, the development of the reproductive system becomes "sweeping" again, very quickly, leaving other organs in the whole body far behind. So, what changes do boys have during their sexual development?
1. the development of male reproductive organs
Male reproductive organs include penis, scrotum and testis, epididymis, seminal vesicle and prostate.
The penis is a male sexual organ. Generally, it will not exceed 5 cm before puberty, and it will grow rapidly between the ages of 12 and 13, and will grow to about 12 cm by the end of adolescence. Even mature men who have completed their youth development can have great differences, just like people are tall and short, but they generally do not affect their functions. The front end of the penis is the glans penis, which is the most sensitive part because it is covered with nerve fibers. The glans of infants and young children are covered with a layer of skin called "foreskin". After accelerating the development of youth, or approaching the mature age, the foreskin will gradually retract, exposing the glans penis. But many people's foreskins are still very long when they are adults. In this case, as long as they always pay attention to hygiene, turn the foreskin up and clean it to prevent dirty things from accumulating inside, it will neither affect their health nor affect their sexual function.
Testis is the most important internal genitalia of men. Oval, with a pair, exists in male scrotum. Testis has two main functions: producing sperm and secreting androgen, which can directly affect the development of male reproductive organs and the appearance of secondary sexual characteristics. During the fetal period, the testicles are in the abdominal cavity and then descend into the scrotum after birth. Some boys have no testicles in the scrotum, or only one side has testicles, indicating that the testicles are still in the abdominal cavity. This is the so-called "cryptorchidism", and patients should be operated as soon as possible before they are two or three years old.
The size of testis is often expressed by volume in the medical field. /kloc-less than 3 ml before 0/0, and less than 2 cm in diameter. After 10 years old, the volume increases obviously. According to the survey, 18+0 years old average 19 ml, 12 years old average 6. 1 1 ml, 13 years old average 9.34 ml, 14 years old average 9.34 ml. 15 is13.50ml, 16 is15.55ml, 17 is16.66ml, 18 is17. The above data is only an average. In fact, the growth rate of testicular size is also related to the mature type of people. For example, 14-year-old children with early development, the size of testicles can exceed that of 16, 7-year-old children with late maturity, which is also a common normal phenomenon.
How can you tell whether you are normal or leave early and return late? The simplest way to judge is to guess with reference to the changing process of your height. Because every child has a particularly rapid growth period in adolescence, which is called "height peak". If you can record your annual height growth in adolescence, then the fastest growing year is the age when the growth rate reaches its peak. Generally, precocious boys can reach the peak of growth rate at the age of 12 ~ 13, normal boys at the age of 14 ~ 15, and late-maturing boys can reach the age of 16 ~ 17 at the latest. The development law of reproductive organs such as testis is basically consistent with the change of adolescent height.
With the enlargement of testis, its structure and function have changed accordingly. Boys can produce sperm similar to adults at the age of 18. Sperm mixed with mucus secreted by prostate, seminal vesicle and urethral gland is called semen. A certain amount of semen will be excreted if it is not absorbed by the body after being stored in the body for a certain period of time. This process is called "spermatorrhea". It was also called "the first spermatorrhea" when it first appeared. According to the survey, the average age of the first spermatorrhea is about 16 years old, and the earliest spermatorrhea appears at1~12 years old, but there may be no mature sperm in these semen. After the first spermatorrhea, there will be another spermatorrhea every ten days and a half months. These are normal physiological phenomena.
2. The emergence of male secondary sexual characteristics
After entering adolescence, it seems that the body surface changes of boys are more obvious than those of girls. He changed from a naughty and lovely hooligan to a big man with a deep voice. He has a beard on his face, and the Adam's apple in the middle of his neck is gradually protruding. His shoulders are wide and his chest is wide, and his limbs become strong and strong. In this way, the morphological differences between men and women are growing. All these physical characteristics that distinguish men from women are always called male secondary sexual characteristics. It is the gradual emergence of these secondary sexual characteristics that makes mature men have special masculinity and male ability.
In the process of male secondary sexual characteristics, the change of hair is the most prominent. Among them, pubic hair first appeared, with an average age of about 1 1 ~ 12. It first appeared on both sides of the penis root, and then gradually spread to the perineum, and the color changed from light black to thick curly. In the late adolescence, coarse hair also grows in the middle of the abdomen and chest, while pubic hair is rhombic from below the navel to the vulva. These signs indicate that boys are approaching sexual maturity.
Axillary hair begins to grow one to one and a half years after pubic hair appears. A few people can also be earlier than pubic hair. The appearance of beard is about one year after the appearance of armpit hair, or earlier. At this time, the hairline of the forehead gradually moved back, especially at the temple, becoming a unique hairline for men.
Adam's apple began to appear at about 12 years old, which is the result of the enlargement of larynx and the lengthening of vocal cords under the action of androgen, so the boy's voice area gradually became thicker from 13 years old, which is called "voice change period". When 18 years old, the development and voice change of Adam's apple are mostly completed. In addition, it is worth mentioning that about 1/2 ~ 2/3 boys will also have breast development, which often starts from one side, mainly manifested as nipple protrusion and lump under areola, and some may also have mild tenderness, which usually lasts for half a year to one year, and then subsides spontaneously. Therefore, the procedure of male adolescent sexual development is generally testis, penis, pubic hair, armpit hair, beard, Adam's apple, voice change and so on. However, this is just the usual rule. In fact, the difference in puberty development of each boy is greater than that of girls, so the emergence procedures of various secondary sexual characteristics of some boys do not conform to this law, and most of them are normal phenomena. Especially the change of hair, most orientals are not as developed as westerners. Some people have sparse pubic hair, armpit hair and beard even when they reach sexual maturity. The size and length of internal and external reproductive organs are also very different. As long as it is not obvious abnormality, it will generally not affect sexual function in the future, so no special treatment is needed.
Testicular will produce sperm in the future, so it is a boy's reproductive organ. Interstitial cells on seminiferous tubules in testis separate a large amount of androgen from a small amount of estrogen, so they are important endocrine organs for boys. Before puberty, the testis is in a naive state, the volume is less than 3 ml, and the seminiferous tubules that produce sperm in the testis are thin and can't see the lumen. 10 years old, seminiferous tubules began to develop, and a small number of spermatogonia appeared on the tube wall. At about the age of 12, the testis developed rapidly and its volume increased to more than 12 ml. The length and curvature of seminiferous tubules increase, spermatogonia on the wall of seminiferous tubules continue to divide and multiply, gradually develop into spermatogenic cells at all stages, and finally produce sperm, and androgen is separated from interstitial cells.
Sperm produced in testis is not yet fully mature, and continues to absorb nutrients and develop after entering epididymis. The vas deferens is next to the tail of epididymis, forms an ejaculatory duct with the excretory duct of seminal vesicle, and leads to urethra through prostate.
Testis-epididymis-output vas deferens-ejaculatory duct-urethral orifice is the only way to expel sperm.
With the development of testis, accessory glands such as seminal vesicle gland, prostate gland and urethral ball gland also mature rapidly, and each secretes milky viscous liquid with special pungent smell, which is very important for the survival and activity of sperm.
In childhood, the scrotum skin is delicate and fine, and after puberty, it gradually increases with the development of testis, resulting in pigmentation. The elastic fibers under the scrotum have good elasticity. When it is cold, it shrinks into wrinkles to keep warm, and when it is hot, it expands to help dissipate heat, thus ensuring the development and function of testicles at room temperature. The penis consists of three sponges, and the front end expands into a glans with a urethral orifice. The penis begins to develop at the age of 1 1- 14. It is about 1-2 years later than testicular enlargement. 15- 16 years old, developed like an adult, with erectile function and first nocturnal emission.