What is Puberty?
This is the period of 12-14 years of age in which the individual becomes functionally capable of reproduction. The start of the ovarian activity and production of the ovarian hormones bring it about. The time of onset of puberty is variable according to race, family and environment.
Before the onset of puberty, anterior pituitary produces growth and other tropic hormones, but does not produce gonadotrophins. The ovaries lie quiescent.
If stimulated by proper hormones the anterior pituitary and ovary are capable of full function even before puberty. It is the hypothalamus, which withholds production of gonadotrophin releasing hormones and keeps in check the secretion of FSH and LH by the anterior pituitary. Consequently the ovaries remain inactive.
At puberty, due to increased activity of the anterior pituitary, production of the gonadotrophins starts. They act on the ovaries and cause maturation of the primordial follicles into Graafian follicles. These produce estrogens. These hormones act on the genital tract, breasts, bones and general metabolism of the body. The following chances are seen during puberty.
Development of the secondary sexual characters
The secondary sexual characters develop in the following order:
The ducts of the mammary glands proliferate under the influence of estrogens (Thelarche) and fat deposition between the ducts increases. The breasts increase in size and become more prominent.
2) Pubic and Axillary Hair
The growth of hair on mons veneris and in the axillae starts at puberty. The adrenocortical steroids influence the growth hair rather than the estrogens (Adrenarche).
It becomes wide. The typical female curves appear due to deposition of subcutaneous fat at certain areas.
Menarche means onset of menstruation at 12-14 years of age. It is one of the changes occurring at puberty. The ovarian hormones, estrogens and progesterone, act on the endometrium. The endometrium becomes thick and is shed cyclically on withdrawal of these hormones. Age of menarche varies with family, social class, diet, general health and environment. Initial menstrual cycles are irregular and anovulatory but soon they become regular and ovulatory.
5) Body Growth
At puberty, prior to menarche, there is a surge of hormones. This leads to rapid increase in growth of the body. Later, under the influence of estrogens closure of epiphyses takes place; hence the body growth stops by the age of 18 years.
6) Skin changes
Acne: Acne spots may appear on the face. The cause of these spots is not known, but they may be due to androgens produced by the adrenal cortex.
Pigmentation: There is increased pigmentation of the skin especially on the vulva. It is perhaps, due to increased production of melanocyte stimulating hormone (MSH).
Growth of the genital tract
The genital tract, under the influence of ovarian hormones, grows and increase in size.
The body of the uterus increases in size and changes from the infantile type of the adult type.
The vaginal epithelium increases in thickness due to storage of glycogen in its superficial and intermediate zones. Doderlein’s bacilli appear in the vagina and its PH becomes acidic. The labia majora becomes more prominent due to deposition of subcutaneous fat.
At puberty, girls become shyer, modest and blush easily and become interested in boys. They are also moody and may have a volatile temper.