3 Ventilation Flashcards
What do we call the air inhaled during a normal breath?
Tidal Volume
~ 500ml
What do we call the air we can force out after a normal expiration?
The expiratory Reserve Volume (ERV)
~1100ml
Name the maximum volume of air we can inhale after a normal inspiration?
The Inspiratory Reserve Volume - IRV
~3000ml
What is the base level of air in the lungs that we can’t expel?
Residual Volume - RV
~1200ml
What is the vital capacity - VC?
The variable level of air in the lungs. I,e, the total amount you can inhale/exhale apart from the residual volume.
~4600ml
How do we calculate the vital capacity?
Sum of:
- Inspiratory Reserve Volume
- Tidal Volume
- Expiratory Reserve Volume
How do we determine total lung capacity - TLC?
Total:
Vital Capacity & Residual Volume
~5800ml
What is the inspiratory Capacity - IC?
The total amount you can inspire in one forced breath.
Tidal Volume + Inspiratory Reserve Volume
~3500ml
What is the Functional Residual Capacity - FRC?
Resting level of air in lungs during normal breathing
I.e. Residual + Expiratory reserve volume
~2300ml
Summary of Lung volumes and capacity
What is the FEV1?
Forced Expired Volume in 1 second.
What is FEV1:FVC?
A ratio of the vital capacity that can be expired in 1 second in a forced breath.
Can be experssed as a %
What does ventilation broadly refer to?
The movement of air in and out of the body?
What are the 2 types of ventilation?
Pulmonary (minute) - Total air movement in/out of lungs
Alveolar - Fresh air reaching the alveoli & available for gas exchange.
What is ventilation measured in?
L/min
What is hypo/hyperventilation?
Hypoventilation is low alveolar ventilation
Hyper is high alveolar ventilation
How we determine the partial pressure of a gas as part of a gas mixture?
Multiply the % of that gas in the mixture by the total pressure of the mixture.
(All gasses exert the same pressure)
What is atmospheric pressure?
101kPa
760mmHg
What is normal Alveolar ventilation?
~4.2L/min
Whats the normal partial pressures for oxygen & CO2 in the alveoli?
PO2 = 13.3kPa (100mmHg)
PCO2 = 5.3kPa (40mmHg)
How do partial pressures change during hyperventilation?
PO2 rises (~120mmHg)
PCO2 falls (~20mmHg)
What happens to partial pressures during hypoventilation?
PO2 falls (~30mmHg)
PCO2 rises (~100mmHg)
What are the different lung volumes for males and females
