# Shared Flashcard Set

## Details

Respiratory System
Mechanics of Ventilation Part II
10
Physiology
02/20/2012

Term
 Lung Volume During a Respiratory Cycle:-Static Lung Volume-Dynamic Lung Volume
Definition
 Static Lung Volume- 3.2 LitersDynamic Lung Volume- 3.7 LitersStatic Lung fully filled until expiration, and the dynamic lung volume decreases to 3.2 liters
Term
 Lung Pressure-Intrapleural Pressure (Static --> Dynamic --> Static)-Transpulmonary Pressure (Static --> Dynamic --> Static)
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 expirationTranspulmonary 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.
Term
 Alveolar Pressure During Respiratory Cycle
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
Term
 Airflow (V with dot) During Respiratory Cycle
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
Term
 2 Effects of Negative Transpulmonary Pressure during inspiration
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
Term
 Effect of Airway Resistance on the Rate of Lung Inflation
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
Term
 Effect of Airway Resistance on Tidal Volume
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
Term
 Effect of Respiratory Frequency on Tidal Volume
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
Term
 Equation for Airflow
Definition
 V (with dot) = P(b) - (P(a)/R(aw))
Term
 Equation for Airway Resistance (R(aw))
Definition
 R(aw)= P(a) - (P(b)/V(with dot))
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