Flashcards in Matt and Mike's Review Deck (18):
What is Anatomic Dead Space (Conductive System) and what branches are included?
A. Anatomic Dead Space has NO gas exchange
B. Has Ventilation but NO Perfusion
C. Consists of branches 0-16:
2. Main Bronchi
3. Lobar Bronchi
4. Segmental Bronchi
5. Terminal Bronchi
What is Ventilation and in what zone of the lung is it greatest?
1. Ventilation (V) is Air flow
2. Base of the Lung has HIGHEST Ventilation per unit Volume
What is Perfusion and in what zone of the lung is it greatest?
1. Perfusion (Q) is Blood Flow
2. Base of the Lung has the HIGHEST Perfusion
Why is the V/Q relationship important and what are its values at the Base and Apex of the Lung?
1. V/Q is instrumental to gas exchange
2. At the Apex there is low Q, so V/Q > 1
3. At the Base there is high Q, so V/Q < 1
Explain the Graph of Pulmonary Vascular Resistance. How does an increase in PO2 (Volume) change it?
1. PVR is a sum of Extra-Alveolar Resistance and Alveolar Resistance making it J-shaped (Optimal is at bottom of J)
2. Increase PO2 causes:
A. Decreases Extra-Alveolar Resistance
B. Increases Alveolar (Capillary) Resistance
C. Increases Recruitment and Vasodilation
What are Type I Pneumocytes?
Flattened epithelial cells that are used for gas exchange
What are Type II Pneumocytes?
1. Large Cuboidal cells that secrete Surfactant
2. Can differentiate into Type I Pneumocytes
What is Hysteresis and what causes it?
1. Hysteresis is the difference between the curve for INHALATION and the curve for EXHALATION in the Pressure vs. Volume curve
-Inhalation is more right
2. Caused by Surfactant REDUCING the Surface Tension
At INCREASED Lung Volumes, what happens to Pulmonary Vascular Resistance of Extra-Alveolar Vessels?
At INCREASED Lung Volume the PVR of Extra-Alveolar Vessels is DECREASED
At INCREASED Lung Volumes, what happens to Pulmonary Vascular Resistance of Alveolar Vessels (Capillaries)?
At INCREASED Lung Volume the PVR of Alveolar Vessels (Capillaries) is INCREASED
What are the 4 Factors that DECREASE Airway Resistance (PVR)?
1. INCREASE Lung Volume
2. DECREASE BRONCHIAL CONSTRICTION
3. DECREASE Density (less crowded = less resistance)
4. DECREASE Forced Expiration
What does Surfactant do?
REDUCES SURFACE TENSION in less expanded lungs, enhancing alveolar stability, and PREVENTING COLLAPSE
What makes the Pressure vs. Volume curve different for Saline Inflation opposed to Air-Inflated Lungs?
1. Saline reduces surface tension so there is easier to fill
2. NO Hysteresis
3. Positive Compliance so Steeper Curve at Lower Pressure
The slope of the Volume vs. Pressure graph translates into what?
1. Increased Compliance (Emphysema) increases slope
2. Decreased Compliance (Pulmonary Fibrosis) decreases slope
What is Fick's Law?
Diffusion or "Vgas" = (A/T) x D x ∆P
What is the formula for the Alveolar Gas Equation?
Alveolar O2 or "pAO2" = FiO2 x (Atmospheric Pressure - 47) - (pACO2/R)
-FiO2 is fractional concentration (% ÷ 100)
-Atm is 760 at sea level
-R is respiratory Quotient (0.8)
What is the formula for the A-a Gradient?
A-a Gradient= pAO2- paO2