A girl walks along a dusty road and breathes through her nose…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A girl walks along a dusty road and breathes through her nose.
- Name two things in the nasal chamber that catch the dust.
- Besides clearing the air, what two other things does the conducting part do to it?
- The inner surface of her lung slides over the chest wall as she breathes. Which fluid makes this smooth?
- The thoracic chamber is air-tight. Why does this matter for breathing?
Need a reminder? The key ideaShow
Different animals use different organs: body surface, moist skin, tracheal tubes, gills or lungs. In humans the air passes through the nostrils, nasal chamber, pharynx, larynx, trachea, bronchi and bronchioles (the conducting part) to the alveoli (the exchange part). The trachea divides at the fifth thoracic vertebra.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. (a) The hairs and the mucus of the nasal chamber catch the dust.
Step 2. (b) The conducting part also humidifies the air and brings it to the temperature of the body.
Step 3. (c) The pleural fluid, between the two pleural layers, reduces friction on the lung surface.
Step 4. (d) Because the chamber is air-tight, a change in the volume of the chest is passed on to the lungs. That is how the movements of the chest move the air.
Answer: (a) hairs and mucus; (b) humidifies it and warms it to body temperature; (c) the pleural fluid; (d) the chest volume and the lung volume change together.
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