What does antral follicle mean?

Ovum, 2-8mm in diameter. The eggs can be accurately measured and counted using ultrasound. According to ultrasound, we can see that the diameter of the antral ovum is 2-8mm. Antral ovum is also called resting ovum.

Antral ovarian development

Uterine development goes through three stages: recruitment, selection, and optimization.

It takes about 85 days for an egg to grow and develop to its final perfection. The whole process of fertilization takes a period of 1 to 4 days, and its mechanism may be related to factors such as the amount of follicle-stimulating hormone (FSH) protein or the state of the microenvironment of the egg. Fundraising is necessary for ovulation, but it does not necessarily occur after ovulation. Selection refers to the process in which one of the collected egg clusters develops into a mature follicle and has the ability to ovulate. On days 5 to 7 of the cycle, the selected eggs are finally selected after being locked by other eggs. The stage between the selection of nearly mature follicles and ovulation is the egg promotion process.

1. Primordial egg

Diameter 0.03～O. 06mm, each oogonia has 46 sex chromosomes, undergoes mitosis, and is composed of primary oocytes and surrounding unilateral flat precursor granulosa cells. The primordial egg produced in the ovarian cortex is continuously transferred to the ovarian medulla to provide a source for the next cycle of uterine development.

2. Primary and secondary coil eggs

At this time, the single-sided squamous epithelial cells change into cubic granulosa cells, which contain primary and secondary oocytes with a diameter of more than 0.06mm. After the secondary coil oocyte is produced, the following key changes occur in the granulosa cells: production of ovulation hormone, estrogen and testosterone protein kinase, production of gap junctions, and production of oocyte membrane. Granular cells produce and metabolize mucopolysaccharides, producing the zona pellucida.

3. Antral ovum

When the egg diameter reaches O. When the diameter is 2 to 0.4 mm, fluid is formed between the granular cells and deposited to form a cavity.

4. Mature follicles

The volume increases significantly, the fluid inside the granulosa cell layer gradually increases, the inner cavity also expands, and the egg moves to one side. At this time, the activity of aromatase in the egg is further enhanced, and the metabolism of estradiol reaches its peak. It can also have a feedback regulatory effect on the hypothalamic-pituitary-hypophysial cycle center, causing a surge in the release of gonadotropin, resulting in a pre-ovulatory progesterone conversion to growth hormone (LH) peak and promoting ovulation. Its structure from outside to inside is: ovum outer membrane, ovum endometrium, granulosa cells, ovum cavity, cumulus ovum, and corona radiata. There is also a very thin zona pellucida between the corona radiata and the egg. Just before ovulation, the granulosa cells in the cumulus are loosely arranged. The morphological characteristics of the perfect oocyte are: granulosa cells develop, the distance between cells increases, the radiata cells disperse, and the oocyte extrudes the first polar body, which is the MII stage oocyte.