Ventilation: Perfusion Relationship Flashcards
What are ventilation and perfusion both measured in?
L/min
What is perfusion?
It is the measuring of blood flow through the pulmonary circulation
What would be the most efficient situation with ventilation and perfusion?
If they both mathched each other
What happens to blood flow and ventilation as height increases?
They decrease.
Why is blood flow higher at the base of the lungs?
because the arterial pressure is less than the alveolar pressure and so it compresses the alveoli.
Why is the blood flow lower at the apex of the lungs?
The alveolar pressure is greater than the arterial pressure and so it compresses the arterioles.
Where does the biggest ventilation perfusion mismatch happen?
At the apex of the lung
What decreases faster with height, ventilation or perfusion?
Perfusion.
What are the two types of mismatch (ventilation-perfusion)?
- mismatch 1 (base) - Ventilation < Perfusion < 1
* Mismatch 2 (apex) - Ventilation > Perfusion > 1
Where does the greatest mismatch take place?
in the apex.
How is ventilation matched to perfusion?
Through the pulmonary circulation.
What does shunt mean?
It means blood moving from the right hand side of the heart to the left hand side without going through gas exchange.
What is the local coping mechanism to keep ventilation and perfusion matched?
When the tissue of one area become hypoxic and the smooth muscles of the blood vessels going to that area constrict and so it reduces the blood that flows to that area.
What do blood vessels in the pulmonary circulation do to respond to hypoxia?
They constrict
What do the blood vessels in the systemic circulation do to respond to hypoxia?
They dilate so that they can deliver more oxygen to that region that is lacking oxygen.
