Coordination & Control – the Endocrine System (OCR GCSE Combined Science A (Gateway): Biology)

The lining of the uterus is shed during menstruation.

New cells are needed to replace the lining of the uterus.

Describe the processes that occur to make these new cells.

Hormones are used in some methods of contraception.

(i) Which two hormones are found in the most commonly used contraceptive pills?.

Put a  around the two correct answers.

FSH    Insulin    Oestrogen    Progesterone    Testosterone

[1]

(ii) How does the contraceptive pill containing the two hormones prevent pregnancy?

[1]

Contraceptive hormones can be used by women in different ways.

Method 1

One contraceptive pill is taken every day at around the same time of day for 21 days. Then no pill is taken for seven days.

Fewer than 1 in 100 women will get pregnant in a year if they use the contraceptive pill correctly. However, typically 9 in 100 women will get pregnant in a year.

Method 2

A contraceptive implant is a small flexible plastic rod containing hormones. It is inserted under the skin of a woman by a doctor or nurse. It is reversible and needs replacing after 3 years.

Fewer than 1 in 100 women using the contraceptive implant will get pregnant in a year.

Which method is more successful?

Evaluate the information to explain why.

Non-hormonal contraceptive methods have different success rates in preventing women from getting pregnant. 

(i) Suggest one reason why sterilisation is not widely used in couples without children.

[1]

(ii) The diaphragm is a circular dome made of thin soft latex with a flexible rim.
It fits inside the vagina forming a seal.

Suggest how a diaphragm acts as a contraceptive.

[1]

(iii) The cervical cap is like the diaphragm but smaller. It fits over the cervix.

Explain why the success rate of the cervical cap would be lower than that of the diaphragm.

[2]

(i)Different hormones control the human menstrual cycle.

Complete the sentences to describe how the menstrual cycle is controlled.

Use words from the list.

Each word can be used once, more than once, or not at all.

fetus    follicle    FSH    oestrogen    progesterone

The hormone released by the pituitary gland is called ..................................... .

This hormone acts on the ovary and causes the growth of a ..................................... .

The hormone that maintains the lining of the uterus is called ..................................... .

[3]

(ii) The table shows the concentration of oestrogen in the blood during the first 7 days of the menstrual cycle.

Put a  around the days below which show a steady increase in the concentration of oestrogen.  

  Days 1–4    Days 2–5    Days 3–6    Days 4–7

[1]

Higher tier content only

The graph in Fig. 21.1 shows how the level of progesterone changes during the menstrual cycle.

Fig. 21.1

(i) Draw another line on the lower graph to show how the level of oestrogen changes during the menstrual cycle.

[2]

(ii) Describe how oestrogen and FSH interact during the menstrual cycle.

[2]

Higher tier content only

Endometriosis is a condition where the cells that normally line the uterus (womb) can move to other parts of the body.

During the menstrual cycle the cells that have moved can react in the normal way to the hormones controlling menstruation.
This can cause a number of problems including fatigue and pain.

Explain what happens to the cells that have moved and how doctors could treat the condition using sex hormones.

Use the information from the graph in Fig. 21.1 and your own knowledge.

Higher tier content only

Look at the diagram. It shows changes to the uterus lining during the menstrual cycle.

(i) Which hormone would peak at point X?

 [1]

(ii) Name two hormones that peak immediately before ovulation.

1 ....................................................................
2 ....................................................................

[1]

Higher tier content only

Explain how hormones can be used by women for contraception.

Which hormone works with insulin to control blood sugar levels in the body?

Tick (✓) one box.

Scientists are using human embryonic stem cells to grow cells to treat type 1 diabetes.

Explain why scientists use embryonic rather than adult stem cells.