Question 19M.2.SL.TZ1.a
| Date | May 2019 | Marks available | [Maximum mark: 4] | Reference code | 19M.2.SL.TZ1.a |
| Level | SL | Paper | 2 | Time zone | TZ1 |
| Command term | Outline | Question number | a | Adapted from | N/A |
Outline the process of inspiration in humans.
[4]
a. diaphragm and external intercostal muscles contract ✔
b. diaphragm moves down/becomes flatter
OR
external intercostals raise the ribcage/move the ribcage up/out ✔
c. muscles/diaphragm/intercostals increase volume of thorax/expand the thorax
OR
muscles/diaphragm/intercostals decrease pressure in the thorax ✔
d. as volume «of thorax/lungs» increases the pressure decreases ✔
e. air enters «lungs» due to decreased pressure/higher pressure outside body ✔
f. air flows to lungs through trachea and bronchi/bronchioles ✔
Accept thoracic cavity or chest cavity in place of thorax in any part of the answer.
Do not allow “oxygen” instead of air in mpe or mpf.
The mechanisms used to cause ventilation of the lungs are poorly understood by many candidates, despite them being used throughout our lives. Cause and effect are often confused – air rushes in to cause a volume increase in the lungs for example.
