Measuring volumes in the lungs Flashcards
How does carbon dioxide move?
Carbon dioxide diffuses from blood to alveoli raising levels but slight fall due to mixing with dead air space
How does water vapour move?
The moisture lining in the alveoli evaporates into alveolar air and is then expired
What is the effect of temperature?
Heat lost from the blood raises the temperature of the alveolar air
What is a kymograph?
It is a rotating dum where trace is drawn as it moves up and down
What is the spirometer chamber?
An air tight chamber with lid floating on water and is filled with air or oxygen at the start
What is the counterpoise?
A chamber that only moves when breathing
What is the carbon dioxide absorber?
It is soda lime from exhaled air
What is the purpose of the nose clip?
A person only intakes gas from the chamber
What is the tidal volume?
The volume of air breathed in or out of the lungs per breath
What is the tidal volume in humans?
0.5
How does the tidal volume value change?
The average volume at rest but increases during excercise
What is the vital capacity?
The maximum volume of air that can be forcibly expired after a maximal intake of air
What is the vital capacity in humans?
3.5 - 6
What does vital capacity depend on?
The volume depends on the size and fitness of the person
What is the residual volume?
The volume of air remaining in the lungs at the end of maximum expiration
What is the residual volume in humans?
1.5
What does the value of residual volume represent?
The typical value where inhaled air mixes with residual air, keeping the levels of gases in the alveoli constant
What is the oxygen consumption on the graph?
The gradient
How do you calculate tidal volume?
The average height of a wave on a graph (e.g. 1 box = 0.25dm so 3 boxes = 0.75 dm)
How do you calculate the vital capacity?
From the highest to lowest point on graph
How do you calculate residual volume?
Total lung capacity (use average) - vital capacity
How do you calculate breathing rate?
Number of breaths in 30s (number of waves) x2
How do you calculate ventilation rate?
Tidal volume x breathing rate
What is the gradient?
(Bottom of highest peak to lowest peak) / time
How does oxygen move?
Oxygen diffuses from alveoli into blood, expired air mixes with air from dead space
