Puberty and menstruation in women

2021-06-08 05:27 PM

The onset of puberty is thought to be stimulated by maturation processes occurring in another region of the brain, possibly elsewhere in the limbic system.

Puberty means the beginning of sexual maturity, and menstruation means the onset of the first menstrual cycle. Puberty is caused by increased secretion of the gonadal-regulating hormone by the anterior pituitary gland, with onset at about 8 years of age, usually reaching full maturity, and the onset of menstruation between 11 and 16 years (average 13 years old).

Figure. The total amount of gonadal-regulating hormones secreted during the reproductive years of women and men, showing a particular increase in gonadal-regulating hormones at menopause in women.

In women, like men, the pituitary gland and ovaries are fully functional during pregnancy if they receive the right stimulation. However, as in men, for some reason, the hypothalamus does not secrete enough GnRH to have an effect during childhood. Experiments have shown that the hypothalamus can secret these hormones on its own, but there are several signals from different regions of the brain that prevent the secretion from taking place. Therefore, it is thought that the onset of puberty is stimulated by maturation processes occurring in another region of the brain, possibly somewhere in the limbic system.

Figure. Oestrogen secretion during reproductive age in women

The figure shows (1) an increase in oestrogen secretion during puberty, (2) a cyclical variation throughout the menstrual cycle, (3) an increase in oestrogen secretion during the early reproductive years. , (4) the process of decreasing oestrogen secretion until the end of reproductive age and finally (5) virtually no oestrogen or progesterone is secreted after menopause.