Fig. 1 shows a photomicrograph of part of the lung of a mammal.
Fig. 1
(i)
The two lines drawn on the capillary labelled A represents the diameter of the capillary measured at different points. The two lines on the image have the following measurements:
Diameter 1 = 6 mm
Diameter 2 = 9 mm
Calculate the average diameter of the image of capillary A.
[1]
(ii)
Calculate the actual average diameter of capillary A using your answer to a) i) and the formula:
1mm = 1000 μm
Give your answer to the nearest whole μm.
[3]
(iii)
Make a large drawing of three alveoli and one capillary, that are next to each other in Fig.1. Do not draw individual cells.
[4]
Some students measured the average increase in chest circumference, during breathing, and when at rest. Each student wrapped a tape measure around their body just below the armpits, as shown in Fig. 2.
Fig. 2
Each student then breathed out and took a measurement of their chest circumference. They then breathed in and took a second measurement. The difference between the two measurements is the increase in chest circumference.
Table 1 shows the results of their measurements.
Table 1
| Increase in chest circumference / mm | |
| male | female |
| 40 | 32 |
| 31 | 37 |
| 48 | 25 |
| 28 | 38 |
| 46 | 27 |
| 33 | 30 |
| 39 | 22 |
| 41 | 38 |
| 25 | 27 |
| 39 | 34 |
average | 37 |
|
(i)
Calculate the average increase in chest circumference for females.
Write your answer in Table 1.
[1]
(ii)
Describe how the students could find out the effect of exercise intensity on chest circumference during breathing.
[5]
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