1. Inhalation

2. Exhalation

4. Ventilation. Put the following into columns and in the right order to describe inhalation (inspiration) and exhalation (expiration).
Diaphragm contracts to become flatter and pushes digestive organs down.
Diaphragm relaxes and is pushed up by displaced organs underneath
External intercostal muscles contract to raise the ribs
Volume of chest cavity increases
Air moves out of the lungs
External intercostal muscles relax and ribs fall
Pressure in chest cavity drops below atmospheric pressure
Air moves into the lungs
Volume of chest cavity decreases
Pressure in lungs increases and rises above atmospheric pressure

5. Answers Inhalation Exhalation
External intercostal muscles contract to raise the ribs
Diaphragm contracts to become flatter and pushes digestive organs down.
Volume of chest cavity increases
Pressure in chest cavity drops below atmospheric pressure
Air moves into the lungs
Exhalation
External intercostal muscles relax and ribs fall
Diaphragm relaxes and is pushed up by displaced organs underneath
Volume of chest cavity decreases
Pressure in lungs increases and rises above atmospheric pressure
Air moves out of the lungs
Interactive Iron Lung

6. Calculate your breathing rate
Count how many times you breath in and out in one minute
How would this rate change if you were exercising?
Why?

7. Lung volume Using your books (page 50)
Fill in the definitions on lung volume and label up your diagram.

8. Key words Tidal volume Vital capacity
The volume of air moved in and out of the lungs at rest (aprox 0.5dm3)
The largest volume that can be moved in and out of the lung (aprox 5 dm3)

9. Some more key words Residual volume Dead space
Inspiratory reserve volume
Expiratory reserve volume
Volume of air that always remains in the lungs
Air in the lungs that can not be used in gas exchange (trachea)
The volume of air that can be inhaled over the normal tidal volume
The volume of air that can be expired over the normal tidal volume

10. The spirometer and lung volume

11. Spirometer traces Calculating the oxygen uptake: (diagram a - at rest)
Following the same pattern as below, calculate the oxygen uptake for (b)
Answer = 1.9dm3min-1
Calculating the oxygen uptake: (diagram a - at rest)
Y-axis shows the reduction in chamber total volume by 0.3dm3 between points A&B.
The time taken for this reduction is s
So in 55s 0.3dm3 of oxygen is used up. This gives...
= 0.3 dm3s-1 55
= x 60 dm3min-1 55
= 0.33dm3min-1

12. Tasks
Suggest how a spirometer trace for a trained athlete would differ from a spirometer trace from an untrained individual?
Suggest why traces like those on the previous slide are not started immediately as the subject begins to exercise.
Answer the rest of question 4 from Jan 2002 paper (2802)

13. Plenary activity: Answer question 1 and 2 from Jan 2003 paper (2802)
Homework:
Complete exam question 6 from Jan 2006 paper (2802)

14. Plenary answers