How big is a normal mature follicle?

In the female body, the ovaries are a relatively important reproductive organ. If there is a problem with the ovaries, women may encounter some troubles in getting pregnant. Moreover, if you do not pay attention to the protection of your ovaries, it may affect women's reproductive health and cause them to suffer from some ovarian diseases. The most serious one is ovarian cancer, which can be life-threatening. So, how big is a normal mature follicle?

size

Every month, women will only release one mature egg, and this mature egg is generally considered a mature egg when it is larger than 20mm. However, there are individual differences. Some people will release the egg when the follicle grows to 15mm, while others will release the egg when it grows to 25mm. The specific individual situation can be determined by a periodic B-ultrasound examination. Generally, mature follicles will be discharged within one to two days, and the discharged follicles can generally survive for 2 days.

Developmentally dominant follicle

The primordial follicle is composed of a large primary oocyte and a single layer of flat follicle cells surrounding it. There are about 1 million primordial follicles in the ovarian cortex of newborns, but most of them cannot reach the mature stage. They atrophy and degenerate one after another to form atretic follicles. The development of primordial follicles into growing follicles does not require hormonal regulation.

What are the criteria for a dominant follicle? The primary oocyte of a growing follicle is enlarged, and significant RNA and protein synthesis occurs within the cell. After the follicle cells become cubic or columnar, they rapidly proliferate into multiple layers. A thick membrane is formed between the oocyte and the follicle cells, called the zona pellucida, which is a gelatinous glycoprotein complex. Under the electron microscope, the microvilli on the surface of the oocyte and the protrusions of the follicular cells can be seen extending into the zona pellucida, which is beneficial for the follicular cells to transport nutrients to the oocyte. The zona pellucida plays an important role in identifying sperm species and preventing polyspermy. The follicular cells continue to proliferate, and the small cavities between the follicular cells gradually fuse into a larger follicular cavity, which is filled with follicular fluid containing hyaluronic acid, estrogen and nutrients. The criteria for the dominant follicle: As the follicular fluid continues to increase and the follicular cavity continues to expand, the oocyte and some of the surrounding follicular cells are squeezed to one side of the follicle and protrude into the follicular cavity, which is called the cumulus ovum. The remaining follicle cells that make up the egg wall are densely arranged into several layers, called the granulosa layer. A layer of columnar follicle cells close to the zona pellucida, arranged radially, is called the corona radiata. The connective tissue around the follicle forms two layers of follicle membranes. The inner layer has more cells and is rich in capillaries. The inner layer cells and follicular cells work together to secrete estrogen; the outer layer has more fibers. Starting from puberty, several to dozens of follicles grow and develop in each cycle, but only one follicle matures, occasionally two, and the rest are atretic.