B1.2.2 Hormones

Question 1

What internal conditions need to be controlled in the body? (4 marks)

Answer 1

• water content
• ion content
• temperature
• blood sugar levels

Question 2

How does water leave the body? (3 marks)

Answer 2

• via the lungs when we breathe
• via the skin when we sweat to cool us down
• via the kidneys in the urine

Question 3

How do ions leave the body? (2 marks)

Answer 3

• ions are lost via the skin when we sweat

- excess ions are lost via the kidneys in the urine

Question 4

Why does temperature need to be maintained in the body?

Answer 4

To maintain the temperature at which enzymes work best

Question 5

Why does blood sugar levels need to be maintained in the body?

Answer 5

To provide the cells with a constant supply of energy

Question 6

What are hormones?
Where are they produced?
How are they transported to their target organs?

Answer 6

Chemical substances that coordinate the body.
They are secreted by glands.
They are transported by the bloodstream.

Question 7

The hormones that control the menstrual cycle are produced by which two glands?

Answer 7

The pituitary gland and the ovaries.

Question 8

Which organ secretes FSH?

What does FSH control? (2 marks)

Answer 8

• The pituitary gland.
• It causes eggs to mature in the ovaries.
• It stimulates the ovaries to produce hormones including oestrogen

Question 9

Which hormone stimulates the release of eggs from the ovary?

Answer 9

Luteinising hormone (LH)

Question 10

Which organ secretes oestrogen?

Answer 10

The ovaries

Question 11

What does oestrogen do? (3 marks)

Answer 11

• It inhibits the further production of FSH
• It stimulates the release of LH
• It causes thickening of the uterus lining

Question 12

Why do oral contraceptives contain oestrogen?

Answer 12

Oestrogen inhibits FSH production so that no eggs mature

Question 13

The first birth-control pills contained large amounts of oestrogen, why do birth-control pills now contain a much lower dose of oestrogen, or are progesterone only?

Answer 13

These lead to fewer side effects

Question 14

Which hormones do fertility drugs contain and why?

Answer 14

• FSH and LH

- A woman’s own level of FSH may be too low to stimulate eggs to mature

Question 15

Outline the steps in In Vitro Fertilisation (IVF) treatment. (4 marks)

Answer 15

– A mother is injected with FSH and LH to stimulate the maturation of several eggs.

• The eggs are collected from the mother and fertilised by sperm from the father in a petri dish.
• The fertilised eggs develop into embryos.
• At the stage when they are tiny balls of cells, one or two embryos are inserted into the mother’s uterus (womb)

Question 16

Evaluate the benefits of, and the problems that may arise from, the use of hormones to control fertility, including In Vitro Fertilisation (IVF)

Answer 16

• enables a couple to have children if the female has low FSH levels
• can result in multiple births
• multiple births - higher risks for baby and mother
• treatment is expensive and not always successful, therefore can cause emotional problems