The ovaries are a vital part of the female reproductive system. In this article, we’ll discuss the most important functions of the ovaries, along with their basic anatomy and how they interact with other reproductive organs in processes like ovulation, menstruation and pregnancy.
Functions of the ovaries
The main function of the ovaries is producing and storing the female sex cells which are called ova or eggs. In sexual reproduction, the ovum provides half of the DNA that will make up the genetic blueprint of the offspring, as well as cellular structures that allow the fertilized egg to divide and differentiate to form a new, genetically distinct organism. A woman has two ovaries, each of which contains approximately 400,000 follicles capable of producing an egg. Although women are born with these follicles and “potential” eggs, no mature eggs are actually released until the onset of puberty as a result of rising levels of follicle stimulating hormone (FSH).
The ovaries also serve as part of the endocrine system, responsible for producing and modulating several different hormones in the female body. The hormones produced by the ovaries are the main ones implicated in menstruation and pregnancy: estrogen and progesterone. The follicles produce estrogen to help the eggs mature in preparation for ovulation. Once an egg is released from its follicle, the empty follicle continues to produce estrogen at lower levels while also increasing production of progesterone. Progesterone causes the uterus to prepare for a possible pregnancy by thickening the endometrium (blood-rich lining of the uterus). If the egg is fertilized by a sperm cell and successfully implants in the endometrium, the empty follicle continues producing hormones necessary to sustain the new pregnancy. If the egg is not fertilized before it dies or if a fertilized egg doesn’t implant in the endometrium, pregnancy does not occur and the follicle stops hormone production, causing the uterus to shed its endometrium in the process of menstruation. The cycle begins again once the menstrual period is over.
When women reach a certain age, the follicles in her ovaries no longer produce eggs or the hormones which regulate her menstrual cycle, a period known as menopause. As a result, the woman will no longer ovulate or menstruate and will no longer be able to get pregnant.
Basic anatomy of the ovaries
The ovaries are oval-shaped organs measuring approximately 4 cm across. They are located one on each side of the uterus near the bottom of the abdominal cavity, attached by the Fallopian tubes on one end and a ligament made of connective tissue on the other.
When the brain sends the signal for ovulation to the ovaries in the form of luteinizing hormone (LH) from the pituitary gland, one follicle (usually) releases a mature egg into the Fallopian tube. The egg waits inside the tube near the ovary until it is either fertilized or it dies. If fertilized, it will try to implant in the uterine wall (the beginning of a pregnancy). If it dies, which usually occurs within 12-24 hours, it will leave the body during menstruation along with the bloody tissue of the uterine lining.