What happens when the egg is released from the ovary? 

When the egg is released from the ovary, the lining of the uterus begins to become thicker. 

If the egg gets fertilized, it attaches itself to the wall of the uterus and receives nourishment. 

If the egg is not fertilized, the lining of the uterus is shed. 

This is known as menstruation or periods. Once the wall is shed, it begins to build up again.

This continuous building and shedding of the inner wall of the uterus occur during a menstrual cycle. 

In a mature female, normally one egg is formed during the menstrual cycle. 

The duration of one menstrual cycle is about 28 days. At the end of the cycle, the egg is released from the ovary.