Term
Lung Volume During a Respiratory Cycle:
-Static Lung Volume
-Dynamic Lung Volume |
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Definition
Static Lung Volume- 3.2 Liters
Dynamic Lung Volume- 3.7 Liters
Static Lung fully filled until expiration, and the dynamic lung volume decreases to 3.2 liters |
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Term
Lung Pressure
-Intrapleural Pressure (Static --> Dynamic --> Static)
-Transpulmonary Pressure (Static --> Dynamic --> Static) |
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Definition
Intrapleural Pressure:
-At around -5 cmH2O at empty static lung
-Decreases to -7.5 and stays there until the second static state
*Decreases at inspiration, increases at expiration
Transpulmonary Pressure:
-Same as Pip, but more gradual and linear so that 1/2 full lung is 1/2 down the curve, not all the way down the curve. |
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Term
| Alveolar Pressure During Respiratory Cycle |
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Definition
-0 unders static conditions
-During inspiration, rapidly becomes negative, then back to 0 by the end of inspiration
-During expiration, rapidly becomes positive, then back to 0 by the end of expiration |
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Term
| Airflow (V with dot) During Respiratory Cycle |
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Definition
-0 under static conditions
-during inspiration, rapidly becomes negative then back to 0 by the end of inspiration
-during expiration, rapidly becomes positive then 0 by the end of expiration |
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Term
| 2 Effects of Negative Transpulmonary Pressure during inspiration |
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Definition
1) Body invests energy into making P(a) more negative, resulting in air flowing into the lungs, making lung volume greater.
2) Body invests a greater fraction of energy into making Transpulmonary Pressure more positive, thereby maintaining a higher lung volume.
*Body has now used all energy from the change in Pip (transpulmonary pressure) and no longer expands |
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Term
| Effect of Airway Resistance on the Rate of Lung Inflation |
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Definition
-time constant is a measure of how long it takes to fill the lungs to 63% capacity
-healthy lungs- .2 seconds
-diseased lungs- 1 second
-So, obviously, increased resistance (whether it be by restriction or obstruction) slows airflow |
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Term
| Effect of Airway Resistance on Tidal Volume |
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Definition
-Healthy lungs- lung volume remains relatively steady at increasing frequencies (respiratory cycles/second)
-Diseased Lung- Lung volume decreases at a low respiratory frequency and continues to decrease with increasing respiratory frequencies |
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Term
| Effect of Respiratory Frequency on Tidal Volume |
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Definition
-Change in lung volume decreases as respiratory frequency increases
*makes sense-short frequent breaths leads to a decrease in the change of lung volume over each respiratory cycle |
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Term
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Definition
| V (with dot) = P(b) - (P(a)/R(aw)) |
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Term
| Equation for Airway Resistance (R(aw)) |
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Definition
| R(aw)= P(a) - (P(b)/V(with dot)) |
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