Question 17N.2.HL.TZ0.01e.ii
| Date | November 2017 | Marks available | [Maximum mark: 1] | Reference code | 17N.2.HL.TZ0.01e.ii |
| Level | HL | Paper | 2 | Time zone | TZ0 |
| Command term | Suggest | Question number | e.ii | Adapted from | N/A |
Skeletal muscle contractions can take two different forms: if they are stimulated by a single action potential they take the form of a twitch and if they are stimulated by a series of action potentials the contraction is longer lasting (tetanic). The table shows the effects of hypoxia on the force of twitch and peak tetanic contraction in the diaphragm.
[Source: Reproduced with permission of the © ERS 2011. European Respiratory Journal June 2011, 37 (6) 1474–1481; DOI: 10.1183/09031936.00079810]
Hypoxia caused a 13 % increase in the surface area to volume ratio of the diaphragm. Suggest a reason for this change.
[1]
a. decrease in volume/atrophy/loss of cells/less muscle fibres/less tissue in the diaphragm
b. SA to volume ratio increased to make oxygen uptake into muscle/cells faster
Do not accept reduction in area of diaphragm
[Max 1 Mark]
