6 Questions
What is the approximate percentage of oxygen in expired air?
16%
What is the primary function of the respiratory system?
Supply oxygen to the blood
Where does the exchange of oxygen and carbon dioxide take place?
Alveoli
What is the approximate percentage of nitrogen in inspired air?
79%
Which of the following is NOT a principle function of the respiratory system?
Regulate body temperature
How many alveoli are there approximately in an average adult's lungs?
600 million
Study Notes
Respiratory System
- The primary function of the respiratory system is to supply oxygen to the blood, which delivers oxygen to all parts of the body.
- The respiratory system functions while breathing, involving the exchange of gases at the alveoli.
- The average adult's lungs contain approximately 600 million alveoli, which are spongy, air-filled sacs surrounded by capillaries.
Gas Exchange
- Inhaled oxygen passes into the alveoli and diffuses through capillaries into the arterial blood.
- Waste-rich blood from the veins releases its carbon dioxide into the alveoli, which is then exhaled.
Principle Functions of the Respiratory System
- Ventilation of the lungs
- Extraction of oxygen from the air and transfer to the bloodstream
- Excretion of carbon dioxide and water vapour
- Maintenance of the acid-base balance of the blood
Composition of Air
Inspired Air
- 79% nitrogen
- 20% oxygen
- 0.04% carbon dioxide
- Water vapour and trace gases
Expired Air
- 79% nitrogen
- 16% oxygen
- 4% carbon dioxide
- Water vapour and trace gases
Learn about the primary function of the respiratory system, including the exchange of oxygen and carbon dioxide through the alveoli. This lecture covers the basics of breathing and lung function.
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