10 minutes maximum! Can you do it in 5?


1. The diagram below shows human lungs:

digestive system sketch


Which label A to D shows the bronchioles?

2. When breathing out the path of the air is ..

  • A. trachea → bronchus → bronchioles → alveoli
  • B. bronchioles → bronchus → trachea → alveoli
  • C. alveoli → bronchioles → bronchus → trachea
  • D. alveoli → bronchus → bronchioles → trachea

3. When we breathe in, which of the following occurs to bring air into the lungs?

A. Diaphragm contracts External intercostal muscle contract
B. Diaphragm contracts External intercostal muscles relax
C. Diaphragm relaxes External intercostal muscles contract
D. Diaphragm relaxes External intercostal muscles relax

4. Which of these facts is true for the bronchioles but not the alveoli?

  • A. large surface area
  • B. very good blood supply
  • C. walls are one cell thick
  • D. lined with cilia

The table below shows the percentage by volume of some of the gases in inhaled air and exhaled air:

gas Inhaled air Exhaled air
Nitrogen 78% 78%
Oxygen 20% 16%
Carbon dioxide 0.04% 4%
Water vapour Little saturated
5. What is the difference in percentage composition of oxygen between inhaled air and exhaled air?
  • A. 0.04%
  • B. 4%
  • C. 0%
  • D. 16%
6. Complete the sentence below about breathing:
To  breathe out the air pressure in our lungs must be the air pressure outside our body.


7. Why is tar in cigarette smoke a harmful chemical?
  • A. It causes addiction.
  • B. It causes cancer.
  • C. It makes platelets stick together.
  • D. It sticks to blood vessel walls.
8. Smoking damages the goblet cells and the cilia in the lining of the bronchioles. This causes more mucus to be present in the alveoli. 

Why does this lead to reduce gas exchange and the person becoming breathless?

  • A. The surface area of the alveoli is reduced
  • B. There is less blood supply to the alveoli
  • C. The thickness of the walls of the alveoli is increased
  • D. The concentration gradient between the air in the alveoli and the blood is decreased.

9+10: A student measured her breathing rate at rest. It was 15 breaths per minute. She then ran 400m and measured her breathing rate every minute after she stopped running. The results are shown in this graph:

graph showing breathing rate after excercise

9. How much slower was her breathing rate 4 minutes after exercise compared to 2 minutes after exercise?

  • A. 25 breaths per minute
  • B. 16 breaths per minute
  • C. 9 breaths per minute
  • D 5 breaths per minute
10.   Why did her breathing rate stay high after exercise?
  • A. Her muscle cells needed to get rid of the carbon dioxide
  • B. Her muscle cells needed to get rid of the oxygen.
  • C. Her muscle cells needed more carbon dioxide.
  • D. She was sweating