Ovaries

The ovaries are tiny, oval-shaped glands located on each side of the uterus. They are responsible for producing and storing eggs (also known as ova) while also producing hormones that regulate the menstrual cycle and support pregnancy. 

During ovulation, one of the ovaries releases an egg, which can lead to pregnancy if fertilized by sperm. The ovaries will continue to release eggs with each menstrual cycle until menopause, when they stop releasing eggs altogether. Ovaries can release more than one egg at a time, which can result in a multiple pregnancy.

Ovarian Anatomy

The ovaries are slightly textured and oval in shape. Their color is typically anywhere from white to light gray. 

The average size of one ovary is approximately 4 centimeters but their size can change depending on age. They can be approximately 6 centimeters before menopause (about the size of a kiwi) and 2 centimeters after menopause (about the size of a kidney bean). Studies show that the size of the ovaries decrease every year after their owner turns 30.

Each ovary is made up of three layers. The center or medulla holds blood and lymphatic vessels. That is surrounded by what is called the ovarian cortex which is composed of connective tissue and contains the ovarian follicles. Finally, it is all wrapped up in an outer layer. 

The ovaries are on either side of the uterus in the lower abdomen and are held in place by muscles and ligaments. Something called the ovarian ligament connects the ovaries to the uterus but the uterus and the ovaries do not actually touch.

And no matter what your health class model seemed to indicate, “The ovaries and the fallopian tubes are not connected!” Bianca Palmisano, MSN, RN, SANE explains, “The ends of the fallopian tubes have fimbriae that reach out towards the ovaries and sweep mature eggs in the right direction, but it is not one connected pathway. This is how people sometimes end up with ectopic pregnancies (a pregnancy outside of the uterus) — the egg does not go into the fallopian tubes and sperm swim up and OUT of the fallopian tube into the pelvic cavity, where they meet and implant elsewhere, usually on the outside of the uterus or on the tubes themselves.”

Ovaries and Hormones

The ovaries secrete two key hormones: estrogen and progesterone. Estrogen is at its peak during the first half of the menstrual cycle, just before ovulation, promoting reproductive development and overall well-being. Then, in the second half of the cycle, progesterone levels rise to prepare the uterus for a potential fertilized egg, ensuring a nurturing environment if conception occurs. 

Because of their role of producing estrogen, the ovaries are a key player in the menstrual cycle.

According to Palmisano, “Estrogen is one of the main hormones involved in the menstrual cycle — it encourages the development of a mature follicle which will ‘bud off’ from the ovary, travel down the fallopian tubes and potentially become a fertilized embryo. However, if a person has one ovary removed, for example due to an ectopic pregnancy, torsion, or cancer, the other ovary will continue to regulate their cycle.”

She goes on to say, “A bilateral oophorectomy (the removal of both ovaries) puts the body into artificial menopause.”