3.1.1 Exchange surfaces – Lung volumes Flashcards
(13 cards)
State 2 pieces of equipment that can be used to measure lung volumes.
1) Peak flow meter
2) Spirometer
Why is it important for the subject to wear a nose clip when using a spirometer?
To ensure that all air breathed is breathed in and out through the chamber.
It stops the results from being invalid.
What type of gas is in the chamber for the subject to inhale?
Medical grade oxygen.
Why is soda lime placed in the spirometer chamber?
To absorb the carbon dioxide exhaled.
What happens to the chamber during:
a) Inhalation
b) Exhalation
a) It falls
b) It rises
What is the name of the graph produced by a spirometer?
A kymograph.
On a kymograph, what do the peaks and the troughs represent?
Peak – exhalation
Trough – inhalation
Why does the kymograph trace gradually decrease over time?
The volume of gas decreases due to the carbon dioxide exhaled being absorbed by the soda lime.
What does the ‘tidal volume’ show?
The volume of air breathed in and out at rest.
What does the ‘vital capacity’ show?
The maximum volume of air that can exhaled after maximum inhalation.
How do you calculate ventilation rate?
Ventilation rate = tidal volume x breathing rate
How do you calculate rate of oxygen uptake?
Oxygen uptake = volume of oxygen used / time
If the data from a spirometer is plotted on a lung volume graph, what do the peaks and troughs represent?
Peak – inhalation
Trough - exhalation
