Term
| what are the two types of flow profiles? |
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Definition
| laminar flow and turbulent flow |
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Term
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Definition
| a mixture of both laminar and turbulent flow -- happens when airways bifurcate |
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Term
| what is the equation for flow? |
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Definition
| flow = pressure gradient/resistance |
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Term
| what is the pressure inside the alveoli at FRC? |
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Definition
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Term
| when does dynamic inspiration occur? |
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Definition
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Term
| what happens during dynamic inspiration? |
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Definition
| a) the diaphragm contracts; b) intrapleural pressure becomes more negative; c) alveolar pressure becomes more negative; d) atmospheric air is sucked into the lung; e) lung volume increases. |
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Term
| what happens during static inspiration? |
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Definition
| a) the diaphragm keeps contracting; b) intrapleural pressure plateaus at low pressure; c) alveolar pressures falls back to zero (patent airways); d) lung volume holds at tidal volume. |
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Term
| what happens during dynamic expiration? |
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Definition
| a) diaphragm contractions decrease and cease; b) intrapleural pressure becomes less negative; c) alveolar pressure becomes positive with respect to the atmosphere; d) lung air is pushed out into the environment; e) lung volume passively decreases back to FRC. |
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Term
| what happens during static expiration? |
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Definition
| lung pressures, flow and volume become flat-line traces until the start of the next breath. |
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Term
| Order of events in cause/effect relationship of the breathing cycle? |
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Definition
| Intrapleural pressure decreases causing alveolar pressure to fall = flow of air into the lungs = volume in lung increases |
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Term
| How are airflow profiles characterized from the trachea to the several branches of each lung lobe? |
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Definition
| turbulent and airway resistances are high |
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Term
| How are airflow profiles characterized in the smaller conducting airways down to the terminal bronchioles? |
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Definition
| laminar and airway resistances are low |
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Term
| How are airflow profiles characterized beyond the terminal bronchioles? |
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Definition
| diffusive and airway resistance is near zero |
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Term
| where is the highest regional airway resistance in the lungs? why? |
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Definition
| generation 4 because the airways are small/short enough and the flow velocity is high enough to produce turbulence during inspiration |
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Term
| Where does half of the total resistance of the airways come from? |
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Definition
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Term
| Are airway resistances higher or lower at high lung volumes? |
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Definition
| lower because airways are all pulled open which reduces the resistance |
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Term
| Is active expiration from FRC to RV effort dependent or effort independent? |
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Definition
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Term
| Is active expiration from TLC to FRC effort dependent or effort independent? |
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Definition
|
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Term
| What does effort dependent mean? |
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Definition
| airflow out is proportional to the expiratory muscle effort exerted |
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Term
| Is inspiration effort dependent or effort independent? |
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Definition
|
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Term
| is the lung static or dynamic at end-inspiration? |
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Definition
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Term
| During dynamic inspiration is the intrapleural pressure positive or negative? |
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Definition
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Term
| During dynamic expiration is the intrapleural pressure positive or negative? |
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Definition
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Term
| How do you measure FVC using an electronic spirometer system? |
|
Definition
| Have the pt slowly inhale to TLC, hold his breath, then explosively exhale to RV |
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Term
| What is the FEV1/FVC ratio? |
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Definition
| Forced expiratory volume in one second divided by forced vital capacity. it is used to diagnose obstructive and restrictive lung diseases. |
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Term
| What is the normal range of values for FEV1/FVC? |
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Definition
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|
Term
| What would the FEV1/FVC value be for asthma(obstructive)? |
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Definition
|
|
Term
| What would the FEV1/FVC value be for pulmonary fibrosis (restrictive)? |
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Definition
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Term
| What two factors determine the time it takes to fill an alveolus? |
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Definition
alveolar compliance (C) and alveolar resistance (R)
Time constant (TC) = C x R |
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Term
| What is the "work of breathing"? |
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Definition
| it costs oxygen burning in respiratory muscles to secure oxygen for the entire body |
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Term
| What 2 restrictive diseases decrease the compliance of the lung and increase the work of breathing? |
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Definition
pulmonary fibrosis
rib cage arthritis |
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Term
| What 2 obstructive diseases increase airway resistance and increase the work of breathing? |
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Definition
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|
Term
| what type of drugs are given to reduce airway resistance in asthma (which is caused by smooth muscle contraction) |
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Definition
| beta2-adrenergic agonists |
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|
Term
| How is the driving pressure for expiration calculated? |
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Definition
| alveolar pressure - intrapleural pressure |
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