Diffusion Flashcards
Diffusion
5 things
- Partial pressure
- Laws of diffusion
- Diffusion and perfusion limitations
- Oxygen uptake along the pulmonary capillary
- Measurement of diffusing capacity
Partial Pressure
Definition
Partial pressure of gases in solution
Partial pressure doesnt equal?
How do gases dissolve in fluids?
Law of Diffusion
The alveolar capillary membrane is the ideal medium for gas diffusion why?
CO2 diffuse ____ than 02
Rate of diffusion in relation to?
Ficks law
Diffusion and Perfusion limitations
What gases are each?!
Oxygen uptake along the pulmonary capillary
Normal PaO2 of blood?
PAO2?
Time in capillary?
What happends during exercise?
- The PaO2 (blood) is normally 40 mm Hg; only 0.3 µm away, PAO2 (alveoli) is 100 mm Hg.
- At normal condition, blood spends about 0.75 second in the capillary. The PaO2 reaches that of the alveolar gas after about one-third of it.
- On exercise, the time is reduced to perhaps 0.25 second. Blood may not be fully oxygenated in disease state.
Diffusing capacity test
What does it measure?
Single breath test what is the patient asked to do?
How is the transfer of CO limited?
Why does that matter?
Objectives
Ficks law states?
Examples of Perfusion, Diffusion limited gases
What is Oxygen limited by?
How is the diffusing capacity measured?
Perfusion and its Matching with Ventilation
8 things
- Pulmonary and bronchial circulation
- Pulmonary vascular resistance
- Distribution of blood flow (perfusion)
- Ventilation-perfusion matching
- Regional gas exchange in the lung
- Mismatching in diseases
- Hypoxemia
- Hypoxic pulmonary vasoconstriction
Pulmonary and Bronchial Circulation
Bronchial circulation is part of the?
Pulmonary circulatoin receives?
Other notes about pulm
Pulmonary Vascular Vessels
The behavior of the caps and the larger blood vessels in lungs is so different they are often called?
Alveolar vessels? 4 points
Lung volume increases —-> chain of events
increase
Extraalveolar vessels
Resistance of both alveolar and extra-alveolar vessels are greatly affected by? WHy?
Decrease
Total pulomonary vascular resistance
- Decrease, Increase, Increase
- Increase increase, decrease
- Increased all around
Recruitment and Distensibility
Pulmonary vascular resistance usually decreases with?
Distribution of perfusion
Distribution of Perfusion
Zones
Ventilations perfusion matching
Ventilations perfusion matching
The alveolar pressure of both O2 and CO2 are determined by?
Two extreme? Results in?
Ventilations perfusion matching
In a normal lung
What kind of patern is seen?
Why is there a sharp increase?
Which zones are usually over or underventilated?
Mismatching is diseased lungs
Normal, Emphysema, Chronic Bronchitis
Hypoxemia
Refers to?
Hypoventilation?
Limitation?
Refers to blood that enters the arterial system without going through ventilated areas of the lung
Primary cause of Hypoxemia?
Hypoxic pulmonary vasoconstriction
Benefitial
Deleterious
Objectives
