Every woman who loves beauty wants to stay young forever, but aging is a natural consequence of the growth process of all living things. The ovaries secrete estrogen and progesterone to maintain our unique female secondary sex characteristics, beautiful face and physique, powerful fertility function, etc. How much do you know about the ovaries? The ovaries are a pair of flat, oval-shaped gonads that are responsible for the maturation and discharge of egg cells, which synthesize and secrete estrogen, progesterone and androgens. The ovaries and the uterus are located together in the pelvic cavity, with the ovaries on the posterior and lateral side of the uterine fundus, adjacent to the lateral wall of the pelvic cavity. The fallopian tube end of the ovary and the upper part of its posterior border are covered by the fallopian tube umbrella and the tubal funnel. If the uterus is compared to an excavator, the fallopian tubes are the “moving arms” and the oviductal funnel is the “bucket”, and the eggs discharged from the ovaries are the ones that will be excavated and “picked up”. In physiological situations such as pregnancy, the ovaries change position dramatically due to the movement of the uterus. After delivery of the fetus, the ovaries usually do not return to their original position, but this does not affect their role; in pathological conditions, such as inflammatory exudate and adhesions and traction in the pelvic cavity near the ovaries, the position of the ovaries may also change to varying degrees. The ovaries, like many organs in the body, are grayish white in color, tough, and flattened in an oval shape. Before sexual maturity, the surface of the ovaries is smooth because ovulation has not yet begun. After sexual maturation, the surface is often uneven because of the expansion of the follicles and the scar tissue left after ovulation. Size of ovaries The size and shape of the ovaries varies with age. In adult women, the ovaries are about 4cm*3cm*1cm, and when women reach middle age, their body functions start to decline and their ovaries start to shrink gradually. The weight of the ovaries is 5~6g, which is equivalent to the weight of a$1 coin. As the body matures and ages, the weight of the ovaries changes. The number of follicles in the ovaries The foundation for female reproductive function is laid in the fetal period, when all the egg cells are produced for life and no more are added later. Once a baby girl is born, her ovaries store 700,000 to 2 million primordial follicles, but not all of them develop to maturity, and only about 400 eggs are actually mature and expelled from puberty to menopause, while more than 99% of the “unfortunate” ones degenerate and die at different times. Ovulation in the ovaries Most women of childbearing age undergo a monthly ovarian cycle, except during pregnancy and lactation, and ovulation occurs 14 days before the next menstrual period. Only one follicle develops per menstrual cycle, which ensures that fertility is “sustainable”. The egg survives for a few hours after ovulation, when it enters the fallopian tube and is fertilized by a sperm. Endocrine functions of the ovaries In addition to ovulation, the ovaries have important endocrine functions. They secrete estrogen, progesterone and a small amount of androgens. During each menstrual cycle, the endometrium changes cyclically in response to changes in the ovaries. After ovulation, due to the combined effect of estrogen and progesterone, the endometrium becomes edematous and the glands produce large amounts of mucus and glycogen, and the thickness of the endometrium thickens from 5-6 mm to 10 mm and above, which is called the secretory endometrium. During the development of the follicle before ovulation, estrogen is synthesized and secreted, and reaches its peak just before ovulation. After ovulation, the follicle wall forms the corpus luteum to synthesize and secrete progesterone and estrogen. The corpus luteum matures 7 to 8 days after ovulation and progesterone secretion is at its peak. If the egg is not fertilized, the corpus luteum begins to shrink 9-10 days after ovulation, sex hormones decrease, and the endometrium sheds and bleeds due to loss of hormonal support, i.e. menstruation. This completes the menstrual cycle and so on and so forth. The ovaries are a “top-down” organ, producing hormones that play an important role in the transmission of hormones to the hypothalamus-pituitary gland and the female reproductive organs. The gonadotropin-releasing hormone produced by the hypothalamus prevents or promotes the secretion of pituitary hormones, while the follicle stimulating hormone and luteinizing hormone produced by the pituitary gland govern the ovaries, promoting follicle development, maturation and secretion of estrogen, and promoting ovulation of mature follicles, formation of corpus luteum and secretion of estrogen and progesterone. In turn, the estrogen and progesterone produced by the ovaries provide feedback information to their “superiors”, the hypothalamus-pituitary gland, which has both negative and positive inhibitory feedback effects. Only when this reproductive axis is functioning properly can the ovaries work properly and the female reproductive system function normally.