| Date | May 2013 | Marks available | 2 | Reference code | 13M.3.SL.TZ1.4 |
| Level | Standard level | Paper | Paper 3 | Time zone | Time zone 1 |
| Command term | Outline | Question number | 4 | Adapted from | N/A |
Question
Scientists investigated astronauts’ cardiovascular response to exercise in weightless conditions during a Columbia Space Shuttle mission. They measured the blood pressure and the time between heartbeats, both at rest and during moderate exercise. Blood pressure is expressed by two values corresponding to ventricular contraction (systole) and relaxation (diastole). Measurements were taken before the flight, early in the flight and during the second week in space. The following graphs represent average values for each type of measurement.
Calculate the difference in blood pressure at systole between rest and exercise before flight, giving the units.
Outline the response of the astronauts’ cardiovascular system to exercise before the flight.
Discuss whether the cardiovascular system has to adjust to weightless conditions in space.
Markscheme
142–117/25 mm Hg (Units required)
a. pressure at systole/diastole / diastolic/systolic pressure increases;
b. pressure at diastole/diastolic pressure does not change much;
c. time between heartbeats decreases / heart beats/rate faster;
Arguments supporting the need for adjustment:
a. (blood) pressure increased but then decreased later in flight;
b. time between heartbeats (at rest) increased then decreased / heart rate decreased then increased;
Arguments not supporting the need for adjustment:
c. (blood) pressure/time between heartbeats/heart rate does not change (much) in space;
d. data is from a few trained astronauts and may not reflect general population / OWTTE;
e. data for more extended periods of time not included (so difficult to evaluate);
Award [2 max] if only one perspective is presented.
Examiners report
A relatively small number of candidates answered this option, but those who did generally achieved well.
In B1 (a) most answers were correct.
A relatively small number of candidates answered this option, but those who did generally achieved well.
In B1 (b) Almost all answers were correct, although some candidates failed to have enough detail for two marks.
A relatively small number of candidates answered this option, but those who did generally achieved well.
Most answers were poor and tended to be descriptive rather than discussions as required.
