EasyBiologyHigh School (9–10)GeneralLife Processes › RespirationHuman Body › Respiratory SystemConceptualBoard Exam
Put these in the order in which air passes them: bronchi, nostrils, alveoli, trachea, pharynx…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Put these in the order in which air passes them: bronchi, nostrils, alveoli, trachea, pharynx, bronchioles, larynx. Which of them keeps its shape with rings of cartilage, and why does it need them?
Need a reminder? The key ideaShow
Air passes through the nostrils, pharynx, larynx, trachea (held open by rings of cartilage), bronchi and bronchioles to the alveoli, where gases are exchanged with the blood. Breathing in, the ribs lift and the diaphragm flattens. Residual air stays in the lungs. Haemoglobin carries oxygen; most carbon dioxide travels dissolved in the plasma.
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. The order. Nostrils, pharynx, larynx, trachea, bronchi, bronchioles, alveoli.
Step 2. The rings. The trachea has rings of cartilage in its wall.
Step 3. Why. When we breathe in, the pressure in the tube falls. The rings stop the trachea from collapsing, so the air passage always stays open.
Answer: nostrils, pharynx, larynx, trachea, bronchi, bronchioles, alveoli; the trachea has rings of cartilage that keep it from collapsing.
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