Term
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Definition
| Movement of air into the lungs and the distribution through the conduction airways to the gas exchange membrane. |
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Term
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Definition
| Movement and distribution of blood through pulmonary circulation |
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Term
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Definition
| Movement of O2 and CO2 across the air-blood barrier. |
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Term
| What determines the mechanical load of the respiratory system? |
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Definition
| Resistance properties of the airways nad elastance of the lungs and chest wall. |
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Term
| What determines the amount of air that reaches the alveolar reservoir? |
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Definition
| The mechanical properties of the system |
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Term
| What are the mechanical properties of the respiratory system that determines the amount of air that reaches the alveolar reservoir? |
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Definition
Strength of pump (inspiration muscles)
Airway resistance.
Elastance/compliance.
Tissue Resistance.
Inertance (E exerted to set system in motion) |
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Term
| What are the forces must be overcome to ventilate the lungs? |
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Definition
Stiffness (elastic recoil) of lungs and chest wall.
Frictional resistance.
Inertance of the system. |
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Term
| What muscles are used for inspiration at rest? |
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Definition
Diaphragm
External intercostals
Accessory muscles (sternocleidomastoids, scalenes, small muscles of the neck and head) |
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Term
| What muscles are used for expiration at rest? |
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Definition
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Term
| What muscles are used for expiration when active? |
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Definition
| Accessory muscles: internal intercostals, abdominal muscles |
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Term
| How does contraction of the diaphragm affect the thoracic cavity? |
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Definition
Increases Diameter.
Increases intrathoracic volume.
Pushes abdominal contents down. |
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Term
| How does the diaphragm contraction affect negative pressure in the thorax? |
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Definition
| It increases the negative pressure by tugging on the lung. |
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Term
| If the thoracic cavity is opened during surgery, what happens to the lung and chest wall? |
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Definition
Lung collapses inward.
Chest wall springs outward. |
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Term
| What way do the ribs move during inspiration? |
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Definition
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Term
| What way do the ribs move during expiration? |
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Definition
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Term
| How does the size of the chest cavity change during inspiration? |
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Definition
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Term
| What is the formula for compliance? |
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Definition
| C = Change in lung volume/ change in intrapleural pressure |
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Term
| What is the relation of compliance to elastance. |
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Definition
| Compliance is inversely related to elastance. |
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Term
| What determines the compliance on the Pressure-Volume loop? |
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Definition
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Term
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Definition
| The phenomenon that compliance of inflation and deflation differs. |
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Term
| What is Transpulmonary pressure? |
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Definition
| Alveolar Pressure minus pleural pressure (distending pressure) |
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Term
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Definition
| Mutual attraction at sides and bottom only |
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Term
| How does detergent affect surface tension? |
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Definition
| It breaks it and interrupts the polar attraction of water molecules. |
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Term
| Where is surfactant synthesized? |
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Definition
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Term
| What is responsible for hysteresis? |
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Definition
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Term
| What is the purpose of surfactant? |
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Definition
| It promotes stability of alveoli of differing sizes and prevents alveolar collapse. |
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Term
| How does lower surface tension affect compliance of the lung? |
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Definition
| It increases the compliance of the lung and reduces the work of expanding it with each breath. |
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Term
| What causes neonatal respiratory distress syndrome? |
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Definition
| Lack of surfactant => hypoxemia, atelectasis, difficulty inflating lungs. |
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Term
| How do you test for respiratory distress syndrome? |
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Definition
| Mesuring the ratio of lecithin:sphingomyelin (>2 is a mature level of surfactant) |
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Term
| How do you determine resistance in the airways? |
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Definition
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Term
| What is poiseuille's law? |
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Definition
R = 8lη/πr4
η= viscosity
r= radius
l = length
Used for laminar flow |
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Term
| What causes bronchodilation? |
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Definition
| Beta2 adrenergic receptors. |
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Term
| What causes bronchoconstriction? |
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Definition
Vagal innervation (parasympathetic)
Ach, methacholine
histamine
decrease in PACO2
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Term
| What is tissue resistance? |
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Definition
| The pressure to overcome the viscous forces within the tissues as they slide over one another. |
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Term
| What is the equation for transpulmonary pressure? |
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Definition
| Pl(transpulmonary pressure)=Palv(alveolar pressure)-Ppl(pleural pressure) |
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Term
| What happens to alveolar pressure during inspiration? |
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Definition
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Term
| What happens to alveolar pressure during expiration? |
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Definition
Increases:
Becomes greater than atmospheric pressure. |
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Term
| How do the calculations of laminar and turbulent flow differ? |
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Definition
Laminar Flow:
R = 8lη/πr4
Turbulent Flow:
Driving pressure proportional to square flow (V2) |
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Term
| When is turbulence most likely to occur? |
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Definition
| When velocity is high and tube diameter is large |
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