In the early days of human life, there was hardly much difference between men and women. However, in the process of gestation, growth and development, under the control of chromosome 23, men and women began to show differences in some organs. Let's look at some interesting homologous organs.
chest
When it comes to breasts, we think of women first. Indeed, breasts are an important symbol of women's secondary sexual characteristics. Although men also have breasts, they are often ignored because of their low level of development, which makes their lofty status among women eclipsed.
In childhood, both male and female breasts are in a "dormant" state, and there is not much difference between them. Just like a thunder, 2-3 years before menarche, that is, 10 years old, women's breasts began to wake up, and under the command of the chief engineer-hormone, the development of breasts as a "pillar" and "framework" accelerated; On this basis, adipose tissue is abundant, so that the breast enters the most active period of physiological development and functional activities in life. So two towering "buildings" were propped up from the airport-like "flat land".
However, the magical process of "high-rise buildings rising from the ground" has nothing to do with male breasts, because the development of breasts requires the synergistic effect of endocrine hormones such as estrogen, progesterone and prolactin, and male breasts are not awakened by these supervisors, so they continue to remain silent.
However, male breasts are not completely inactive. In adolescence, there are still 40%-70% boys with different degrees of breast development. It is characterized by nodules in the breast accompanied by local pain. Most of them can subside in 1-2 years, so don't be too nervous. It should be noted that you should not touch and stimulate the breast frequently at this time, because too much stimulation is not conducive to the regression of breast hyperplasia tissue. In addition, some parents will give their children some nutrition and health products, and some tonics contain hormones, which will cause abnormal breast development of boys, so special attention should be paid.
Clitoris and penis
The name clitoris comes from the Greek Kleitofis, which means "hiding", revealing its low-key and unknown character. In reality, there are indeed many people who don't know this organ that will accompany them for life.
The clitoris lives at the junction of the upper end of the female labia minora, which is a small protrusion like mung bean. Of course, for different individuals, their size, shape and position may be different, some are just a little bigger, and some may be obese because of too much androgen in the body or taking some drugs containing androgen.
The clitoris consists of a pair of sponges that can erect and expand, which are divided into clitoris and clitoris head, and are wrapped in a dense capsule. Speaking of which, people often think of penis. Yes, they are very similar in structure and organization, but the clitoris is deeply hidden. Only a mung bean-sized head emerges from the foreskin of the clitoris, which is the only visible part. Many women's clitoris heads are deeply buried, and they are only willing to show their heads when they are strongly excited.
In fact, the clitoris and penis are homologous and developed from the same structure during the embryonic period. It is because of gender differences and the role of hormones that it has not developed into a look.
Testis and ovary
Testis and ovary, one is responsible for producing sperm and the other is pregnant with eggs; One is engaged in the production and secretion of androgen, and the other is engaged in the production and marketing of estrogen and progesterone. One is located outside the abdominal cavity, in the scrotum, and the other is hidden in the abdominal cavity. Seemingly different in shape and position, they all come from the "embryonic reproductive ridge" in the embryonic stage, and then differentiate and develop along their own paths.
Between men and women, such homologous organs abound. For example, the vas deferens and fallopian tubes transport sperm and eggs, scrotum and labia majora, prostate and female paraurethral glands, respectively. ...
In the Book of Changes, men and women are interrelated, and the difference between the homologous organs of the two sexes is precisely the adaptation of human beings to the environment in the long evolution process. For example, sperm is afraid of heat, and abdominal temperature is harmful to it. Therefore, in order to create a more suitable environment, testicles migrate from abdominal cavity to scrotum in vitro during fetal growth.
Similarly, in order to meet different functions and needs, some functions have been enhanced, such as women's breasts and men's penises; Some functions degenerate or even hide, such as male breasts and female clitoris.