The transition from childhood to adolescence is "the second birth of life", which psychologists call "the second crisis". If the first crisis of life-"weaning crisis" is spent in a warm infancy, the child's resistance is at best a powerless struggle and hopeless crying.
Then, the second crisis of life-psychological "weaning" from parents, came quickly. At this time, a series of significant physiological changes will occur in the body, which is the best period for male growth and development. There are great changes in both morphology and physiology.
It is mainly the development of secondary sexual characteristics, such as voice thickening, beard and armpit hair growing, reproductive organs gradually maturing, pubic hair, enlarged testicles and penis, mature gonads and nocturnal emission. Personality has also become mature, sophisticated, stable and confident, and is no longer as naive and ignorant as a child.
Recent studies show that the initiation of puberty is regulated by a physiologically active substance called gonadotropin, which affects development and makes it secrete sex hormones to maintain the development of secondary sexual characteristics and reproductive and sexual functions. At the beginning of male puberty, the level of gonadotropin PSH rises, which promotes the gradual development of testis.
Spermatogenic tubules develop well, spermatogenic cells mature and produce sperm. At the same time, the level of gonadotropin CH also increased, which promoted the development of leydig cells in testis, produced testosterone, and promoted the further development of male reproductive organs and the development of secondary sexual characteristics.