Ovary

The ovary (lat. ovum: egg; Gr. ooforon) is the female gonad, which secretes sexual hormones and produces the gamete called an ovum. They are organs located inside the pelvis (one on each side) with an ovoid shape and about three centimeters in diameter.

Embryology

Primordial germ cells arise from the yolk sac and migrate under the control of stem cell factor through the primitive gut to the dorsal mesentery and then laterally to the gonadal cristae.
Upon reaching the developing XX genital ridges, the primordial germ cells proliferate as oogonia and subsequently enter meiosis.
Proliferating oogonia in association with somatic cells divide into radially oriented irregularly shaped ovigerous cords open to the ovary surface.
Somatic cells are closely associated with oogony and together they become primordial follicles.

Anatomy

The ovaries are located inside the female pelvis, on the sides of the uterus with which they connect. They are almond-shaped, paired structures, with measurements of approximately 1x2x3 cm, in fertile women (although it varies during the cycle), and with a weight of about 6 to 7 grams, which show a grayish white color. The ovaries are attached to either side of the uterus.

Peritoneum

The ovary is the only intraperitoneal organ that is not completely covered (i.e. deperitonized), since the posterior sheet of the peritoneum that forms the broad ligament of the uterus stops abruptly in the ovary when it comes into contact with the ovarian epithelium at level of the Farré-Waldeyer line.

Secure measures

Ligaments and Mesos del Ovario.

The ovary has support measures to fix it in a position that are:

• The uterus-ovarian or ovarian ligament: goes from the medial or uterine pole of the ovary to the bottom of the uterus.
• The suspensory ligament: is directed from the tubaric pole of the ovary to the abdominal wall.
• Mesoovary: joins along the uterus.
• Mesosalpinx: fix the ovary to the uterine tubes.
• The tube-ovarian ligament: joins the ovary with the flag of the fallopian tube.

Irrigation

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Ovaries, Arteries and veins.

Irrigation of the ovary is given by the gonadal artery or ovarian artery, a direct branch of the abdominal aorta, which passes to the ovaries through the suspensory ligaments. This artery anastomoses with the second source of irrigation of the ovary, the ovarian branches of the uterine arteries, which arise from the internal iliac arteries.

Histology

Complete ovary, cross-cutting. 1: external involt, 2: central skeleton, 3: albug, (peripheral scent), 4: blood vessels

The ovary is made up of an external envelope of simple cuboidal epithelium, arranged on the tunica albuginea of dense connective tissue.

• Cortez The germinal epithelium and ovarian follicles, the underlying stroma is the albuegone area, which contains dense connective tissue.
• Medula Very vascularized and inerve lax connective fabric that continues with the mesoovary through the hilium.

Physiology of the ovary

The ovaries have two interrelated functions: one is steroidogenesis, that is, the production of steroid-type hormones, and on the other hand, gametogenesis whose mature gametes are the ovules.

Ovary gamete

The ovum is the haploid sex cell (gamete) of the ovary of the female animal. On the surface of the ovary, an ovarian follicle ruptures and releases a tertiary oocyte, a process called ovulation.

Ovarian Hormones

The main ovarian hormones it produces are estrogen and progesterone. Estrogens are responsible for the growth of the endometrium during the proliferative phase of the menstrual cycle. Progesterone is the hormone that prevents the shedding of the glycogen-rich endometrium during the secretory phase of the menstrual cycle, and inhibin, which prevents the secretion of FSH from the pituitary. With the help of these hormones, the egg will end up implanting itself in the endometrium. Small amounts of testosterone are also produced in the ovary.

Functions

At puberty, the ovary begins to secrete increased levels of hormones, causing secondary sexual characteristics to begin developing in response. The ovary changes in structure and function from this stage in life. Since the ovaries regulate hormones, they play an important role in pregnancy and fertility. When oocytes are released into the fallopian tube, a variety of feedback mechanisms stimulate the endocrine system, which causes hormone levels to change. These feedback mechanisms are controlled by the hypothalamus and the pituitary gland.

Gamete production

The ovaries give rise to the periodic production and release of ova, the female gametes. In the ovaries, developing oocytes mature in follicles, which are filled with fluid. Usually only one oocyte develops at a time, but others may also mature simultaneously. Follicles are made up of different types and numbers of cells depending on the stage of their maturation, and their size is indicative of the stage of development of the oocytes they contain.

When the oocyte completes its maturation in the ovary, a surge of luteinizing hormones secreted by the pituitary gland stimulates the release of the oocyte through the rupture of the follicle, in a process called ovulation. The follicle remains functional and reorganizes in a corpus luteum, which secretes progesterone in order to prepare the uterus for eventual implantation of the embryo.

Ovarian Aging

As women age they experience a decline in reproductive performance that leads to menopause. This phenomenon is related to a drop in the number of ovarian follicles.
Although about a million oocytes are present at birth in the human ovary, only about 500 of these—about 0.05%—ovulate, while the rest atresate. The decline in ovarian reserve appears to occur at a steadily increasing rate with age, leading to almost complete depletion of the reserve at around 52 years of age. As ovarian reserve and fertility decline with age, there is also a parallel increase in failed pregnancies and errors in meiosis resulting in embryos with abnormal chromosomes.
Ovarian reserve and fertility are optimally maintained between 20 and 30 years of age. Above the age of 45, the menstrual cycle begins to change and the number of follicles decreases significantly. The events that lead to ovarian aging remain unclear; individual variability of ovarian aging could include environmental factors, lifestyle habits, or genetic factors.

Women with an inherited mutation in the BRCA1 DNA repair gene experience premature menopause, suggesting that naturally occurring DNA damage in oocytes is repaired less efficiently in these women, leading to to early reproductive failure. A variety of test methods can be used to determine fertility based on maternal age. Many of these tests measure the levels of the hormones FSH and GnrH.
Methods such as measuring AMH (antimüllerian) hormone levels and AFC (Antral Follicle Count) can predict ovarian aging. AMH levels serve as an indicator of this aging since the quality of the ovarian follicles can be determined.

An experimental treatment for these patients is to administer platelet-rich plasma into the ovary on day 8 or 9 of the menstrual cycle, in order to recover ovarian activity. To verify the effectiveness of the technique, the AMH hormone is studied, which increases its level.^{[citation required]}

Pathology

Among gynecologic conditions, ovarian tumors represent the most difficult diagnostic problems. In the ovaries, benign or malignant, cystic or solid tumors, epithelial, conjunctive, functioning histology or teratomas can develop. In an ovary, the transition from a benign to a malignant lesion is subtle. Several factors, including genetic, embryological, structural, and functional, interact to determine an enormous tumor capacity, whether benign or malignant.

Benign ovarian tumors are cysts and tumors. The most frequent benign tumors of the ovary derive from the development of the ovarian follicle and are cystic formations originated by an abnormal stimulus of the follicle or by alterations in the process of its involution. Most benign cysts and tumors do not cause any symptoms, although some are associated with pain or a feeling of heaviness in the pelvis. Noncancerous (benign) ovarian tumors are benign cystic teratomas (dermoid cysts), solid masses composed of connective tissue and Cystadenomas.

Malignant type neoplasms present a very diverse histology, either of epithelial origin, of origin in the gonadal stroma and finally, of origin in the germ cells.

Oophorectomy

Oophorectomy is the surgical process that involves the removal of one or both ovaries. It is then called unilateral or bilateral oophorectomy. This operation can be performed through the abdomen by laparoscopic surgery or by conventional surgery. When it is from both ovaries, it leaves the woman unable to produce eggs and hormones, entering the menopause of surgical origin. In cases in which the patient is a carrier of a non-cancerous ovarian tumor, only the affected ovary is removed, the remaining ovary being able to supply all functions. In case of benign ovarian cysts, usually only the cyst is removed.