Term
| What determines the elastic recoil of the lung and chest wall? |
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Definition
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Term
| What determines the frictional resistance of the airways and of the tissues of the lung and chest walls? |
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Definition
| Air flow (not by changes in volume) |
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Term
| What determines the inertance or impedance of acceleration of the respiratory system? |
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Definition
| Rate of airflow (negligible during quiet breathing) |
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Term
| What causes airflow through a tube? |
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Definition
| A pressure difference between the two ends of the tube |
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Term
| How is air flow calculated? |
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Definition
| (Change in pressure)/(resistance to airflow) |
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Term
| What determines the difference in pressure in respiration? |
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Definition
| Barometric pressure at the open mouth, and the pressure at the alveolus |
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Term
| Resistance to laminar air flow is dependent on what? |
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Definition
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Term
| How is resistance calculated? |
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Definition
| (Change in Pressure)/(Flow)or 8Ln/pr^4 with n representing viscosity of air |
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Term
| Resistance to airflow is dependent on what? |
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Definition
| Whether it is laminar or turbulent |
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Term
| What is the difference in calculation between resistance in laminar vs turbulent airflow? |
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Definition
R(laminar) = Pressure * k * flow rate
R(turbulent) = Pressure * k * (flow rate)^2 |
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Term
| What criteria must be met for laminar flow in small airways such as alveoli? |
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Definition
| Low airflow, flow is parallel to the walls of the airways, is silent |
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Term
| What are the three areas of air flow resistance in the respiratory system? |
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Definition
| Airway resistance, pulmonary resistance, chest wall resistance |
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Term
| What passageway in the lungs generates the greatest resistance to airflow(80% total resistance)? |
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Definition
| Large bronchi (small airways have higher resistance but contribution to total resistance is low) |
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Term
| Does the airway of the lungs exist in parallel or in series resistance? |
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Definition
| Parallel (1/R = 1/R1 + 1/R2...) |
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Term
| Airway resistance + lung parenchyma resistance is equivalent to what? |
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Definition
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Term
| What inward force helps determine the diameter of an airway? |
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Definition
| Smooth muscle and elastic forces |
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Term
| What outward force helps determine the diameter of an airway? |
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Definition
| Positive transpulmonary pressure and interdependence of alveoli and terminal bronchioles |
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Term
| Does airway resistance increase or decrease with increasing lung volume? |
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Definition
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Term
| What is the relationship between conductance and resistance? |
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Definition
| Conductance = 1/Resistance |
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Term
| What purpose does elastic recoil have on normal breathing? |
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Definition
| Normal exhalation is passive due to lung elastic recoil |
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Term
| How does smooth muscle tone regulate resistance in airway? |
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Definition
| Constriction = increased resistance to airflow, dilation = decreased resistance to airflow |
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Term
| What factors constrict bronchial smooth muscle? |
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Definition
| Parasympathetic stimulation, Ach, histamine, serotonin, decreased PCO2 in small airways |
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Term
| What factors dilate bronchial smooth muscle? |
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Definition
| Sympathetic stimulation via beta-2-AR, beta-2 addrenergic agonists, NO, increased CO2 in small airways, decreased O2 in small airways |
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Term
| What are the most common causes of increased airway resistance? |
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Definition
| Swelling of bronchial wall (edema), obstruction, bronchospasm (constriction of smooth muscle) |
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Term
| What is dynamic compliance? |
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Definition
| The change in volume of the lung divided by the distending pressure during the course of a breath |
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Term
| How is dynamic compliance calculated? |
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Definition
| As the slope of the line between the end-inspiratory and end-expiratory points |
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Term
| What effect does increased resistance have on dynamic compliance? |
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Definition
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Term
| What effect does increased surfactant have on dynamic compliance? |
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Definition
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Term
| When is dynamic compliance roughly the same as static compliance? |
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Definition
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Term
| When is dynamic compliance larger than static compliance? |
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Definition
| Higher respiratory rate and tidal volume (exercise) |
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Term
| When is dynamic compliance lower than static compliance? |
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Definition
| During shallow and rapid breathing |
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Term
| How are alveoli affected by increased resistance? |
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Definition
| Fill more slowly, more ventilation will be distributed to the other alveoli |
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Term
| How are alveoli affected by decreased compliance? |
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Definition
| Less volume filling alvoeolus during inhallation |
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Term
| When does muscle contraction used to facilitate exhalation begin? |
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Definition
| Before the start of exhalation |
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Term
| Why is greater effort will unable to increase the flow rate of exhalation? |
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Definition
| Higher pleural pressure will tend to collapse the airway (airflow is independent of total driving pressure) |
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Term
| When does dynamic airway compression occur in healthy individuals? |
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Definition
| Forced exhalation (ex. coughing) |
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Term
| Where does premature airway closure occur in patients with lung disease? |
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Definition
| Smaller airways lacking cartilage (equal pressure point is closer to the alveolus) |
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Term
| What is characteristic of the respiration of patients with high elastic respiratory work as in restrictive pulmonary diseases? |
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Definition
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Term
| What is characteristic of the respiration of patients with high resistive respiratory work such as in obstructive pulmonary disease? |
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Definition
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