Ventilation & diffusion Flashcards
What are the conducting airways?
Divisions 1-16 - dead space - bulk flow - no gas exchange
What are the respiratory airways?
Divisions 17-23 - alveoli for gas exchange via diffusion
What is hypoxic constriction?
There is a dense capillary network around the alveoli. If there is low o2 in certain alveoli, vessels can constrict and divert blood to areas of high o2
What is the diffusion barrier?
- Alveolar wall
- Epithelial cells of alveolus
- Tissue fluid & connective tissue
- Endothelial cell of capillary
- Plasma
- Red cell membrane & cytoplasm
When has o2 fully saturated Hb?
When its 25% along capillary
What is tidal volume?
Volume of air moved in & out of lungs in normal breathing
What is the inspiratory reserve volume?
Extra volume over that can be breathed in at rest
What is the expiratory reserve volume?
Extra volume over that can be breathed out at rest
What is residual volume?
Volume left in lungs following max expiration
What is total lung capacity?
(TV+IRV+ERV+RV)
Total volume of air present in lungs at end of max inspiration
What is inspiratory capacity?
(IRV+TV)
Biggest breath that can be taken from resting expiratory level
What is vital capacity?
(IRV+TV+ERV)
Measured from max inspiration to max expiration (biggest breath)
What is functional residual volume?
(ERV+RV)
Volume of air remaining in the lungs at the resting expiratory level
What is total/minute ventilation?
Amount of air moved in and out of lungs per min.
What is the alveolar ventilation rate?
The amount of air that actually reaches the alveoli per minute
