The main element of the ovaries in a woman is the follicles, which contain an egg. Around it are two epithelial layers and two layers of the connective shell.
Follicles on the ovaries - norm
The follicular reserve of a woman's ovaries is laid at birth, at this moment there are about 400 thousand and up to 2 million. Prior to puberty in the ovaries are primordial follicles, their size - up to 200 microns, they contain oocytes of the 1 order, the development of which stopped in 1 prophase meiosis.
From the birth of a girl to the teenage age, the maturation of the follicles does not occur, and only during the sexual development begins the growth of follicles, and out of them come out the first ovules. The number of follicles in the ovaries of each girl is different, but on average their norm at the beginning of puberty is about 300 thousand.
Follicular apparatus of the ovaries: follicles
Each ovarian follicle before the release of the egg, passes through the following stages of development:
- A primordial follicle containing an immature egg in the follicular epithelium, around which there are shells from the connective tissue. Each menstrual cycle begins to grow more follicles (from 3 to 30), of which ovaries form preantral follicles.
- Primary (preantral) follicles grow, their oocyte is surrounded by a membrane, and in cells of the follicular epithelium, estrogens begin to be synthesized.
- Secondary (antral) follicles begin production of follicular fluid in the intercellular space containing estrogens and androgens.
- Tertiary (preovulatory) follicles: from a large number of secondary follicles, one becomes dominant, the amount of follicular fluid in it increases 100 times during the developmental period, and the size of several hundred micrometers grows to 20 mm. The egg is located on the egg-bearing tubercle, and in the fluid of the follicle, the level of estrogens is maximized, the remaining secondary follicles are overgrown.
Ultrasound of the follicles during their development
To determine the growth of the follicle in the ovary during the menstrual cycle, ultrasound is carried out on certain days. Until the 7th day of the cycle, the follicles are almost not determined, but on the 7-9th day the growth of secondary follicles in the ovaries begins. These are small follicles and their size can reach up to 4-8 mm. Multiple follicles on small ovaries during this period may indicate ovarian hyperstimulation, the use of contraceptives, and a violation of the hormonal background in the body (decrease in the level of LH).
Normally, on the 7-9th day in the ovary there are few maturing follicles, and in the future, only one dominant follicle in one ovary continues to grow, although at the beginning of maturation the second ovary also contains secondary follicles. The dominant follicle on ultrasound looks like a circular anehogenous formation up to 20 mm in size. The absence of dominant follicles in the ovaries for several cycles may be a symptom of infertility in women.
The causes of abnormal follicle development, diagnosis and treatment of disorders
Follicles on the ovaries may not grow at all, do not develop to the right size, ovulation may not occur, and as a result,
To determine the cause of abnormalities in the development of follicles, not only ultrasound is prescribed, but also the determination of the level of sex hormones in a woman. Depending on the level of hormones in the blood in different phases of the cycle, the gynecologist prescribes drugs that suppress or stimulate the synthesis of tez or other hormones, treatment with sex hormones, and, if necessary, surgical treatment.