Outcomes:

> Be able to state what happens during the menstrual cycle.

> Be able to explain why females have periods.

> Explore what happens at different times during the menstrual cycle.

The menstrual cycle

The female reproductive system includes a cycle of events called the menstrual cycle. It lasts about 28 days, but it can be slightly less or more than this. The cycle stops while a woman is pregnant. These are the main features of the menstrual cycle.

• The start of the cycle, day 1, is when bleeding from the vagina begins. This is caused by the loss of the lining of the uterus, with a little blood. This is called menstruation or having a period.

• By the end of about day 5, the loss of blood stops. The lining of the uterus begins to re-grow and an egg cell starts to mature in one of the ovaries.

• At about day 14, the mature egg cell is released from the ovary. This is called ovulation. The egg cell travels through the egg tube towards the uterus.

• If the egg cell does not meet with a sperm cell, the lining of the uterus begins to break down and the cycle repeats.

Activity: cut out and arrange the sections of worksheet "The menstrual cycle 1" to show how the lining of the uterus changes during the menstrual cycle.

Answer the questions and add the labels on the same page in your book.