Podcast
Questions and Answers
What is the primary function of the alveoli in the lungs?
What is the primary function of the alveoli in the lungs?
What is the average diameter of an individual alveolus in the human lung?
What is the average diameter of an individual alveolus in the human lung?
What is the thickness of the walls of the alveoli?
What is the thickness of the walls of the alveoli?
What is the approximate number of alveoli in the human lungs?
What is the approximate number of alveoli in the human lungs?
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Where does the exchange of respiratory gases (oxygen and carbon dioxide) occur?
Where does the exchange of respiratory gases (oxygen and carbon dioxide) occur?
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What is the role of the capillaries in the respiratory system?
What is the role of the capillaries in the respiratory system?
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What happens to the deoxygenated blood as it passes through the capillary beds around the alveoli?
What happens to the deoxygenated blood as it passes through the capillary beds around the alveoli?
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What happens to the carbon dioxide in the deoxygenated blood as it passes through the capillary beds around the alveoli?
What happens to the carbon dioxide in the deoxygenated blood as it passes through the capillary beds around the alveoli?
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What is the purpose of the extensive network of bronchioles in the lungs?
What is the purpose of the extensive network of bronchioles in the lungs?
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What is the main purpose of the dense network of capillaries surrounding the alveoli?
What is the main purpose of the dense network of capillaries surrounding the alveoli?
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Study Notes
Diffusion in Humans
- In the lungs, oxygen and carbon dioxide molecules diffuse down their own concentration gradients between the moisture on the inner lining of the alveoli and the blood.
- This diffusion occurs down a concentration gradient.
Air Sacs and Alveoli
- Alveoli are perfectly adapted for the process of diffusion, having thin and moist walls that help oxygen and carbon dioxide to diffuse.
- A single alveolus has a thin wall, one cell thick, and is surrounded by a dense network of capillaries.
- The capillaries also have very thin walls, which helps the diffusion of oxygen and carbon dioxide into and from the blood.
How the Alveoli and Capillaries Work
- Air containing oxygen enters the lungs and passes into each alveolus from outside.
- Deoxygenated blood containing carbon dioxide comes from the rest of the body.
- Oxygen diffuses into the blood from the alveoli, while carbon dioxide diffuses from the blood into the alveoli.
- The blood becomes oxygenated, and oxygenated blood leaves the lungs and returns to the heart.
Inhaled and Exhaled Air
- Inhaled air into the lungs: 20.95% oxygen, 79% nitrogen, 0.04% carbon dioxide, and 0.01% water vapor.
- Exhaled air out of the lungs: 16% oxygen, 79% nitrogen, 4.0% carbon dioxide, and 1% water vapor.
Breathing
- Breathing is the process of moving air in and out of the lungs.
- Breathing is achieved by making the chest cavity larger or smaller, which results in a change in pressure within the lungs.
- This change in pressure forces air either in (inhale) or out (exhale) of the lungs, known as ventilation of the lungs.
- Inspiration (breathing in) involves the contraction of rib muscles and diaphragm muscle, which increases the volume of the chest cavity.
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Description
Test your knowledge on diffusion in the human respiratory system. Explore topics such as concentration gradients of carbon dioxide and oxygen, the process of diffusion between alveoli and blood, and the differences between inhaled and exhaled air.
