Grade 7- Menstrual Cycle

Reproduction in Human Beings

• Menstrual cycle consists of natural changes that occur to the body of a female human being every month in preparation to pregnancy.

• A menstrual cycle lasts between 28-35 days. However, this can vary between female and from one cycle to the next. The cycle depends on hormones.

• Hormones are chemical messengers in the body.

• They direct the body on what to do and when to do it.

• The menstrual cycle is a process controlled by hormones in the female body.

These hormones include:

1. Oestrogen.

2. Progesterone.

3. Luteinizing hormone.

4. Follicle stimulating hormone.

The menstrual cycle is divided into the following phases:

Approximate day(s)	Event(s)
1-5 day	Bleeding from the vagina begins. This is caused by theloss of the lining of the uterus. This is called menstruation or monthly periods
6-14 days	Blood loss stops. The lining of the uterus begins to regrow and an ovum starts to mature in one of the ovaries.
14-25 days	Ovulation occurs. The ovum travels through the oviduct towards the uterus.
25-28 days	If the egg becomes fertilized by a sperm and attaches itself to the uterus wall, the woman becomes pregnant. If pregnancy does not occur, the uterus lining begins to break down again, repeating the cycle