Airways and lungs that bring oxygen in and remove carbon dioxide.
Air passes through nose, pharynx, larynx, trachea, bronchi, bronchioles to alveoli. Cilia and mucus trap particles. About 300 million alveoli give around 70 square metres of surface.
The nose warms and filters air; the larynx protects the airway; ribs and diaphragm drive breathing. Respiratory centres adjust to demand.
Common mistake: the lungs have no muscle; breathing depends on surrounding muscles.
Airways and lungs that bring oxygen in and remove carbon dioxide.
Respiratory System is one of the 51 topics in Human Physiology. It is rated Beginner, so it suits learners who are starting out in biology. Related topics in this area include Gas Exchange in Alveoli, Respiratory Control, Circulatory System.
Smoking paralyses cilia and damages alveoli.
Respiratory System is a Beginner topic, so no earlier topic is required. Other Beginner topics in Human Physiology that pair well with it include Homeostasis, Tissues and Organs, Skeletal System.
The closest topics to Respiratory System are Gas Exchange in Alveoli, Respiratory Control, Circulatory System, Excretory System. Comparing them side by side is a good way to see how the ideas connect.
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Respiratory System. To practise the whole of Human Physiology, use the Human Physiology quiz.
Respiratory System: Airways and lungs that bring oxygen in and remove carbon dioxide. Gas Exchange in Alveoli: Oxygen and carbon dioxide diffuse across thin alveolar and capillary walls down concentration gradients. Read both side by side and note what each one explains.
The lungs have no muscle; breathing depends on surrounding muscles.
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Gas Exchange in Alveoli and explain the difference aloud. Finally, take the Human Physiology quiz and come back to this page for any question you miss.
Oxygen and carbon dioxide diffuse across thin alveolar and capillary walls down concentration gradients.
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