Pulmonary Lecture 4 Flashcards
How does gravity affect Regional Variations in ventilation
The top alveolus will have the weight of the lung pulling it open
The bottom alveolus will be squeezed by the wieght of the lung
VBot/VTop = 2.5
The bottom will have more airflow - Volume doesnt matter but change in volume. Because the bottom alveolus is smaller, there is a greater volume change
In this picture will the bottom or top alveolus have more compliance
The bottom alveolus has higher compliance
What are the two characteristics of Oxygen in Blood
- Oxygen is poorly soluble
- Oxygen binding sites on hemoglobin are mostly saturated
How does exercise effect diffusion of Oxygen?
It slows diffusion because blood is flowing more quickly and there is less time for Oxygen to diffuse
How does interstitial disease effect diffusion of Oxygen?
It causes a thickening in the diameter thus causing diffusion to dramatically slow
How is Carbon Dioxide effected by interstital disease or exercise?
Carbon Dioxide is generally never effected by a diffusion problem because it has a much higher solubility. Sometimes it is slow, but not nny much
Blood Flow in the lung
Define Minute Perfusion
Blood flow in the lung in one minute
Normal = 5L
This also equal Cardiac Output as they are so close together
How does Oxygen tension effect Perfusion
Hypoxic Pulmonary Vasoconstriction
It causes areas where oxygen levels are low to constrict.
Mechanism to help divert blood to a part of the lung to have higher gas exchange - adaptive mechanism
How does Capillary Recruitment effect Perfusion?
Have a lung where blood vessels are relatively constricted. When exercising, it causes the blood vessels to dilate recruiting capillaries to allow for a higher gas exchange
How does Gravity Affect Perfusion?
Introduces Regional Variations
Gravity generates regional variation of blood flow at different parts of the lung. If the person is standing upright the blood will pool at base of lung because of gravity. Causes blood pressure below to increase and dilate them.
What is V/Q Mismatch
The ratio of the amount of ventilation that is flowing in and out of the alveolus to the amount of blood flow
If you occlusion of a bronchiole how is V/Q mismatch effected
It will lower
If you have occlusion of an artery how wil V/Q mismatch be affected
It will be higher
If there is a region of low V/Q in the lung, how will the lung compensate?
Other regions V/Q will become higher. This is to maintain normal CO2 Levels