Ovary

The ovary is an important part of the female reproductive system. It is a special organ that makes and releases eggs, called ova. There are two ovaries, one on each side of the body. When an egg is ready, it travels from the ovary through a tube called the oviduct into the uterus, where it may meet with sperm to start a new life.

Ovaries are also like tiny hormone factories. They release different hormones that help control the menstrual cycle and play a big role in fertility, which means the ability to have babies. These hormones help the body know when it’s the right time each month for an egg to be released.

Ovaries start developing before a baby is even born and continue to work through many years of a person’s life. They go through different stages from the prenatal period, when a baby is growing inside its mother, all the way until menopause, when a person stops getting their menstrual cycle. Understanding how ovaries work helps us learn about how bodies grow and change.

Structure

Each ovary is a small, whitish organ located on either side of the uterus in an area called the ovarian fossa. This area is bordered by the external iliac artery, the ureter, and the internal iliac artery. The ovaries are about the size of a small almond.

The ovaries are covered by a tough outer layer called the tunica albuginea. Inside, they have an outer part called the cortex and an inner part called the medulla. Each month, one of the ovaries releases an egg during the menstrual cycle. This egg then travels to the fallopian tube where it may meet with sperm. The ovaries are connected to the uterus by the ovarian ligament and are supported by other tissues and blood vessels.

Function

At puberty, the ovaries start to produce more hormones. These hormones help a girl’s body change and prepare for the possibility of having a baby. The ovaries also release egg cells, which are important for pregnancy.

The ovaries work with other parts of the body to control these changes. They release hormones that affect many body functions, including the menstrual cycle. As girls grow older, the number of egg cells in the ovaries gets smaller, which is a natural part of aging.

Clinical significance

Ovarian diseases can affect how the body makes important messages or how it makes babies. Sometimes, a small lump called an ovarian cyst can form if an egg does not come out of the ovary properly. Many women have these small cysts and are still healthy. In some cases, a woman might have many small parts in the ovary that don’t grow the way they should, which can change how her body works during each month.

Society and culture

Cryopreservation

Preserving ovarian tissue is a way for women to keep their ability to have children later in life or if they need to have treatments for diseases like cancer. Doctors take a small piece of ovary tissue and freeze it safely. Later, the tissue can be used to help make new eggs, allowing a woman to become pregnant naturally.

History

Ancient scientists like Aristotle studied the ovaries and thought they played a role in making babies. Over time, more accurate ideas about how the ovaries work were discovered. Scientists learned that the ovaries produce eggs and that removing them changes a woman’s body. These discoveries helped us understand women’s health better today.

Other animals

Birds usually have just one working ovary, the left one, while the other stays small and unused. In mammals, like humans, the ovary works like the male testicle because both make important body parts and release special chemicals that help the body.

Many animals make far more eggs than humans do. Fish and amphibians can have hundreds or even millions of eggs ready at any time. In birds, reptiles, and some special mammals called monotremes, the eggs are big and change the shape of the ovary when they grow. Some small worms called nematodes can live inside the ovaries of fish and grow very large.

Most animals have two ovaries, but this is not always true. In most birds and platypuses, only the left ovary works, while in some sharks and certain fish, only the right ovary works. In some very old types of fish and a few other fish, there is only one ovary instead of two.

Additional images

• Left ovary

• Ovaries

• Uterus, fallopian tubes, and ovaries

• Right ovary