The menstrual cycle

• Target• To know the menstrual cycle and why it

takes place.

Hormone release

• Hormones produced in the pituitary gland in the brain send signals to the ovaries to release an ova about once per month.

• The ova travels down the fallopian tube to the womb where it may be fertilized by a sperm.

There are three hormones controlling the ova – one causes the egg to mature the other causes the egg to be released. A third hormone oestrogen inhibits further eggs from becoming mature.

Egg stimulated to mature

Oestrogen stops stimulation and starts release.

Egg stimulated to be released

The ova

• This picture shows an ova being released – magnified 2130 times larger than it is in real life.

Menstruation

• This is the process women go through every month to allow the body to prepare to have a baby.

• If the ova is not fertilised it comes away during a ‘period’.

• If it is fertilised the baby starts to grow.

The Menstrual Cycle

The FOUR stages of the menstrual cycle:

Day 1: Bleeding starts when the lining of the uterus breaks down and passes out the vagina – “Having a period”Day 4: The lining starts to build up again and thickens into a spongy layer of blood cellsDay 14 (approx): An egg is released and lasts for around 3 daysDay 28: The lining stays thick awaiting the arrival of a fertilised egg. If one doesn’t come then the lining breaks down again.

Questions1. What do we call the monthly cycle?2. When does this cycle start?3. When does this cycle stop?4. What does the uterus do in this

cycle?5. What do we call it when the uterus

lining breaks down?6. What is another name for periods?

• Menstrual cycle• Puberty• Menopause• Thickens• Period• menstruation