9.3 Alveolar ventilation and factors influencing it Flashcards
What is the equation for total ventilation?
Breathing frequency x tidal volume
What are the two components of air volume?
Dead space - no gas exchange
Alveoli - only gas exchange
What are the two components of physiological dead space?
Anatomical dead space: airways
Functional dead space: ventilated lung parts which are not perfused (0 in healthy person)
What are the roles of the anatomical dead space?
Preparation for gas exchange
- cleaning of air
- water saturation
- temperature control
What is atelectasis?
collapse or closure of the lung resulting in reduced or absent gas exchange
How do you calculate alveolar ventilation?
Total ventilation - dead space ventilation (constant)
What happens to alveolar ventilation during exercise?
There is a linear increases in total ventilation. Alveolar gasses remain relatively stable due to the central control of respiration
What is the difference in translung pressure in an upright person?
Biggest at the top and smallest at the bottom - apex is more inflated than the base
What happens to ventilation at the apex and base?
Ventilation is smallest at the apex and biggest at the base
Where does emphysema begin?
At the apex of the lung
Why is the upper zone of the lung less ventilated?
pleural pressure is larger here and for the same change in pressure there will be a small volume change at the apex
