1. Which gland is known as the "master gland" ?
Answer
Pituitary gland.
2. What is sweat composed of ?
Answer
Water, ions and urea.
3. Name two barrier methods of contraception.
Answer
Condoms and diaphragms.
4. The endocrine system produces hormones. Describe how hormones bring about an effect.
Answer
A hormone is a chemical messenger produced by an endocrine gland and secreted directly into the bloodstream. The blood carries the hormone to a target organ where it produces its effect.
5. Explain why a healthy person's blood glucose concentration does not drop below the normal level.
Answer
If the blood glucose concentration starts to fall, the pancreas releases glucagon. Glycogen is converted back to glucose and released into the bloodstream.
6. Name the substances that are removed from the body by the kidneys.
Answer
Excess water, ions and urea.
7. The glucose concentration in the kidney filtrate of a person is 0.9 g/dm3, while the glucose concentration in the urine of that person is 0.0 g/dm3. Explain this difference.
Answer
Glucose is small and is filtered out of the blood, but all of the glucose is reabsorbed.
8. Several hormones are involved in the menstrual cycle of a woman including follicle stimulating hormone (FSH), luteinising hormone (LH), oestrogen and progesterone. Describe how these hormones interact to control the menstrual cycle.
Answer
FSH causes the maturation of an egg in the ovary and stimulates the ovaries to release oestrogen. Oestrogen causes the uterus lining to thicken, inhibits further release of FSH (so that no additional eggs begin to mature), and stimulates the release of LH from the pituitary gland. LH triggers ovulation — the release of the egg — and inhibits oestrogen production. Progesterone maintains the thickness of the uterus lining and inhibits the release of both FSH and LH.
9. Suggest why some people may have ethical issues with the intrauterine device (IUD).
Answer
As the egg is fertilised but cannot implant, some people may see this as the destruction of a potential human life.
10. Describe some disadvantages of IVF.
Answer
It is very emotionally and physically stressful. The success rates are not high. There can be increased risks to the mother and babies in the case of a multiple birth, and it is expensive.