1.2.3 The respiratory system

1.2.3 The respiratory system

1. functions of the respiratory system

   • to bring oxygen into the body
   • to remove carbon dioxide from the body

2. Gaseous exchange

   • Air passes down the trachea and bronchi into the lungs. It travels through the bronchioles into the alveoli.
   • In the alveoli oxygen diffuses into the blood to be sent around the body.
   • At the same time, carbon dioxide from the body is released into the alveoli where it is exhaled.

3. how the respiratory system works

   • 1. When inhaling the intercostal muscles contract and lift the chest upwards and outwards. The diaphragm tightens and lowers
     • 2. This opens the lungs and creates a vacuum inside so oxygenated air can rush in through the nose and mouth, where it is warmed, moistened and filtered.

4. Inhalation and exhalation

   • Inhale (air into lungs)
     • Oxygen 20.95% (21%)
     • Nitrogen 79%
     • Carbon dioxide 0.04%
     • Water vapour 0.01%

5. Tidal volume and vital capacity

   • Tidal volume is the amount of air inspired and expired with each normal breath at rest or during exercise
   • Vital capacity is the greatest amount of air that can be made to pass into and out of the lungs by the most forceful inspiration and expiration. (4-5 litres)

6. Immediate and short-term effects of participation in exercise and physical activity on the respiratory system

   • Breathing quickens and deepens
   • Oxygen debt
     • When the body works hard, it may need more oxygen than it can get. This is known as oxygen debt
     • 400 m

7. Effects of regular participation in and long-term benefits of exercise and physical activity

   • Increased oxygen delivery
   • Carbon dioxide is removed more efficiently
   • Vital capacity increases
   • Increased number of capillaries
   • More alveoli

8. The effects of smoking on the alveoli and gaseous exchange

   • Smoke damages the lungs, especially the alveoli, making them inflexible and therefore less efficient
     • This means its more difficult to get oxygen in and carbon dioxide out, therefore smokers may become short of breath
       • This requires their hearts to work harder to get the oxygen their bodies need, consequently they feel tired