Describe how air is breathed in, using the rib cage and diaphragm, so that it reaches the alveoli.

Mark scheme

Marking points from the official mark scheme (May/June 2021). The mark or mark type is shown in brackets.

1. [1] contraction of diaphragm ;
2. [1] diaphragm flattens / moves down;
3. [1] bones of rib cage pulled upwards / outwards ;
4. [1] external intercostal muscles contract / internal relax ;
5. [1] pressure decreases / volume increases ;
6. [1] air passes through nose / trachea / windpipe / larynx ;
7. [1] through bronchi / bronchioles ;
8. [1] (effect) bronchi narrowed / blocked by mucus ;
9. [1] (effect) need to cough + remove ;
10. [1] (effect) pain (from coughing);
11. [1] (effect) increase in bacteria / microorganisms;
12. [1] (effect) harder for oxygen to reach alveoli / reduced gaseous exchange ;
13. [1] (effect) reduced aerobic respiration;
14. [1] (effect) ability to exercise reduced ;
15. [1] (effect) feel tired / lethargic;
16. [1] (avoiding) avoid smoking / avoid breathing in smoke ;
17. [1] (avoiding) avoid particulate air pollution / use of mask ;
18. [1] (avoiding) avoid places with lots of vehicles ;