IGCSE Biology 4 Views 1 Answers
Describe the differences in composition between inspired and expired air, limited to: oxygen, carbon dioxide and water vapour
Describe the differences in composition between inspired and expired air, limited to: oxygen, carbon dioxide and water vapour
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The composition of inspired (inhaled) air and expired (exhaled) air differs significantly, particularly in terms of oxygen, carbon dioxide, and water vapor. Here’s a concise breakdown of these differences:
1. Oxygen (O₂)
- Inspired Air: Contains approximately 21% oxygen.
- Expired Air: Contains about 16% oxygen.
- Difference: The decrease in oxygen content in expired air is due to its absorption by the body during respiration for metabolic processes.
2. Carbon Dioxide (CO₂)
- Inspired Air: Contains about 0.04% carbon dioxide.
- Expired Air: Contains around 4% carbon dioxide.
- Difference: The increase in carbon dioxide in expired air results from its production as a waste product of cellular respiration, which then diffuses from the blood into the alveoli.
3. Water Vapor
- Inspired Air: Typically has a lower concentration of water vapor.
- Expired Air: Generally contains a higher concentration of water vapor.
- Difference: The increase in water vapor in expired air occurs because moisture evaporates from the moist surfaces of the respiratory tract and alveoli during exhalation, reflecting body temperature.
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