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An organ found in the female reproductive system that produces an ovum.
When released, the ovum travels down the fallopian tube into the uterus, where it may become fertalised by a sperm.
There is an ovary on the left and the right side of the body.
The ovaries secrete hormones that play a role in the menstrual cycle and fertility.
The ovaries are attach to the Fallopian tubes, and are considered the female gonads.
Each ovary is whitish in color and located alongside the uterus in the ovarian fossa bounded by the external iliac artery and in front of the ureter and the internal iliac artery.
The ovarian fossa is about 4 cm x 3 cm x 2 cm in size.
The ovaries have a surrounding capsule, and have an outer cortex and an inner medulla.
Ovulation usually manifests in one of the two ovaries releasing an egg each menstrual cycle.
In the absence of 1 functional ovary however, the remaining ovary would continue providing eggs for a normal menstrual cycle.
The ovary is connected to the Fallopian tube by infundibulopelvic ligament, and to the uterus via the ovarian ligament.
The ovaries are uncovered in the peritoneal cavity.
The ovaries are tethered to the body wall via the suspensory ligament of the ovary which is a posterior extension of the broad ligament of the uterus.
The mesovarium is the part of the broad ligament of the uterus that covers the ovary
Microanatomy Edit The surface of the ovaries is covered with membrane consisting of mesothelium.
The outermost layer is called the germinal epithelium, and the outer layer is the ovarian cortex.
The ovary consists of ovarian follicles and storms.
Included in the follicles are the cumulus oophorus, membrana granulosa, and the granulosa cells inside it, corona radiata, zona pellucida, and primary oocyte.
In the cortex is the corpus luteum derived from the follicles.
The innermost layer is the ovarian medulla.
Follicles are usually found in the cortex.
At puberty, the ovary secretes increasing levels of hormones, and secondary sex characteristics begin to develop.
At puberty the ability to produce eggs and reproduce develops, as the ovary changes structure and function beginning at puberty.
The ovaries produce and periodical release of egg cells, the female gametes.
In the ovaries, the developing egg cells mature in the fluid-filled follicles.
Typically, only one oocyte develops at a time.
Other oocytes can also mature simultaneously.
Ovulation, the release of the oocyte, occurs when the follicle matures and ruptures following a surge of luteinizing hormone from the pituitary which stimulates the release.
Following release the follicle remains functional and reorganizes into a corpus luteum.
The corpus luteum secretes progesterone in order to prepare the uterus for an eventual implantation of the embryo.
It secretes estrogen, testosterone, inhibin, and progesterone at maturity.
50% of testosterone in women is produced by the ovaries and adrenal glands and released directly into the blood stream.
Estrogen is responsible for the appearance of secondary sex characteristics for females at puberty.
Estrogen is responsible for the maturation and maintenance of the reproductive organs in their mature functional state.
Progesterone prepares the uterus for pregnancy, and the mammary glands for lactation.
Progesterone functions with estrogen by promoting menstrual cycle changes in the endometrium.
With age women experience a decline in reproductive performance that leads to menopause.
Aging is associated with a decline in the number of ovarian follicles.
Although about 1 million oocytes are present at birth in the human ovary.
Only about 500 oocytes (about 0.05%) ovulate.
Females have a fixed number of non-growing follicles in the ovary, with up to 7,000,000 at 20 weeks in utero, up to 2 million at birth, and several hundred thousand at menarche.
Only 12% of pre-birth ovarian non-growing follicles remain by age 30 and oocyte depletion accelerates in the late 20s and 30s, with the mean of 65,000 at 25 years, 16,000 by 35 years and approximately 1000 by menopause.
With aging there is lower fecundity and oocytes develop defects in mitochondrial structure and function and have meiotic spindle dysregulation that increase rates of aneuploidy and miscarriage.
Rates of miscarriage are approximately 12% in women age 20 to 29 years, 25% by 40 years, 40% by 43 years, and 65% in females 45 years and older.
Follicles are decreased by female cigarette smoking, obesity alcohol consumption of > 4 drinks per week and caffeine intake of > 250 mg daily.
The overwhelmingly number of oocytes are wasted.
The decline in ovarian reserve occurs at a constantly increasing rate with age, and leads to nearly complete exhaustion of the reserve by about age 52.
Normal functioning organ produces a follicular cyst 6-7 times each year.
In most cases these functional cystic masses are self-limiting and resolve within the duration of the normal menstrual cycle.
Low response to ovarian stimulation is a strong indicator of diminished ovarian reserve and infertility(Kwee J).
BRCA1 mutations are associated with occult primary ovarian insufficiency and may, in part, explained a link between infertility and breast/ovarian cancer risks (Oktay K ).
The two key functions of the ovary are the production of sex steroids and mature gametes, and they cease at the menopause.
Female fertility is very low for approximately a decade before menopause and is declining during the during the 30s.
The measurement of circulating sex steroids and pituitary gonadotrophins allows assessment of ovulatory function and diagnosis of the main relevant disorders of the ovary.
Ovarian and pituitary hormones do not reflect the activity of the great majority of follicles within the ovary, whose growth is necessary to support ovulation and fertility.
Smaller follicles present in the ovary are determinants of reproductive lifespan and age at menopause.Fox told
As ovarian reserve and fertility decline with age, there is also a parallel increase in pregnancy failure and chromosomally abnormal conceptions.
Women with an inherited mutation in the DNA repair gene BRCA1 undergo menopause prematurely
That suggests that naturally occurring DNA damages in oocytes are repaired less efficiently in these women, and this inefficiency leads to early reproductive failure.
The BRCA1 protein plays a key role in a type of DNA repair homologous recombinational repair.
The BRCA1 protein role in is the only known cellular process that can accurately repair DNA double-strand breaks.
Primordial follicles contain oocytes that are at an intermediate stage of meiosis.
Meiosis is the general process in eukaryotic organisms by which germ cells are formed.
Homologous recombinational repair is especially promoted during meiosis.
Ovarian diseases classified as endocrine disorders or as a disorders of the reproductive system.
If the egg fails to release from the follicle in the ovary an ovarian cyst may form.
Small ovarian cysts are common in healthy women.
Polycystic ovary syndrome, women have more follicles than usual which inhibits the follicles to grow normally and this will cause cycle irregularities.
Ovarian tumors include:
Dysgerminoma
Choriocarcinoma
Yolk sac tumor
Teratoma
Ovarian serous cystadenoma Serous cystadenocarcinoma Mucinous cystadenoma Mucinous cystadenocarcinoma Brenner tumor
Granulosa cell tumor
Krukenberg tumor
Cryopreservation of ovarian tissue is for women who want to preserve their reproductive function beyond the natural limit, or whose reproductive potential is threatened by cancer therapy.
Part of the ovary is removed slowly frozen before storing it in liquid nitrogen.
The tissue can then be thawed and implanted near the fallopian tube where it starts to produce new eggs, allowing normal conception to take place.