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Ovaries

The female gonads are called the ovaries. Ovaries produce eggs and hormones for menstruation and pregnancy. They are found on either side of the uterus. 

In both the males and females, the gonads develop within the mesonephric ridge and descend through the abdomen. However, unlike the testes, the ovaries stop in the pelvis. The ovaries are paired, oval organs attached to the posterior surface of the broad ligament of the uterus by the mesovarium (a fold of peritoneum, continuous with the outer surface of the ovaries). Ovaries play a critical role in both menstruation and conception. They produce eggs for fertilization and they make the hormones estrogen and progesterone. An ovary releases an egg around the middle of menstrual cycle (around day 14 of a 28-day cycle) in a process called ovulation. Each of ovaries has thousands of ovarian follicles. Ovarian follicles are small sacs in the ovaries that hold immature eggs. Each month, between days six and 14 of your menstrual cycle, follicle-stimulating hormone (FSH) causes follicles in one of causes follicles in one of ovaries to mature. At about day 14 in the menstrual cycle, a sudden surge in luteinizing hormone (LH) causes the ovary to release an egg (ovulation). The egg begins its travel through a narrow, hollow structure called the fallopian tube to the uterus. As the egg travels through the fallopian tube, the level of progesterone rises, which helps prepare the uterine lining for pregnancy. If pregnacy don't take place in that cycle, the egg disintegrates and gets reabsorbed by body so menstruation can begin.

The ovaries are intraperitoneal structures. In nulliparae, the ovary lies in the ovarian fossa on the lateral pelvic wall. The ovary is attached to the posterior layer of the broad ligament by the mesovarium, to the lateral pelvic wall by infundibulopelvic ligament and to the uterus by the ovarian ligament.

Mesovarium or anterior border-a fold of peritoneum from the posterior leaf of the broad ligament is attached to the anterior border through which the ovarian vessels and nerves enter the hilum of the gland. Posterior border is free and is related with tubal ampulla. It is separated by the peritoneum from the ureter and the internal iliac artery. Medial surface is related to fimbrial part of the tube. Lateral surface is in contact with the ovarian fossa on the lateral pelvic wall. The ovarian fossa is related superiorly to the external iliac vein, posteriorly to ureter and internal iliac vessels and laterally to the peritoneum separating the obturator vessels and nerves.

The ovary is covered by a single layer of cubical cell known as germinal epithelium. It is a misnomer as germ cells are not derived from this layer. The substance of the gland consists of outer cortex and inner medulla. Cortex: It consists of stromal cells which are thickened beneath the germinal epithelium to form tunica albuginea. During reproductive period (i.e. from puberty to menopause), the cortex is studded with numerous follicular structures, called the functional units of the ovary in various phases of their development. These are related to sex hormone production and ovulation. The structures include primordial follicles, maturing follicles, Graafian follicles and corpus luteum. Atresia of the structures results in formation of atretic follicles or corpus albicans. Medulla: It consists of loose connective tissues, few unstriped muscles, blood vessels, and nerves. There are small collection of cells called "hilus cells" which are homologous to the interstitial cells of the testes.

Arterial supply is from the ovarian artery, a branch of the abdominal aorta. Venous drainage is through pampiniform plexus, that forms the ovarian veins which drain into inferior vena cava on the right side and left renal vein on the left side. Part of the venous blood from the placental site drains into the ovarian and thus may become the site of thrombophlebitis in puerperium. Sympathetic supply comes down along the ovarian artery from T₁, segment. Ovaries are sensitive to manual 10 squeezing.

Published : Dec 17 2023