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28 Cards in this Set
- Front
- Back
Atmospheric pressure (Patm)
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the pressure of the outside air; normal is 760 mmHg
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Intra-alveolar pressure
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the pressure of air w/in the alveoli
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Intrapleural pressure
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the pressure inside the pleural space
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Transpulmonary pressure
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the difference btwn the interpleural pressure & the intra-alveolar pressure
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functional residual capacity
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When the lungs are at rest all breathing muscles are relaxed, and the volume of air in the lungs under these conditions is called __________ _________ _________.
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Pneumothorax
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air in the interpleural space
when air gets into interpleural space the suction is lost and the lung recoils or collapses. |
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Intra-alveolar pressure
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________-________ __________ is determined by the quantity (moles) of air molecules in the alveoli & the volume of alveoli themselves.
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Inspiration
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contraction of the diaphram causes it to flatten & move downward
Meanwhile, contraction of the obliquely oriented external intercostals causes the ribs to pivot upward & outward, expanding the chest wall. |
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Expiration
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As the chest wall and lungs recoil, the volume of the lungs decrease causing alveolar pressure to increase to greater than atmospheric pressure.
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1. the pressure gradient btwn the atmosphere & alveoli
2. airway resistance |
The rate at which air flows into or out of the lungs is determined by 2 factors:
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compliance
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A measure of the EASE w/which they can be stretched.
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transpulmonary pressure
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Lung compliance needs a smaller change in ___________ _______ to bring in a given volume of air, and work or muscle contraction needs to done.
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Lung compliance
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depends on the elasticity of the lungs, and on the surface tension of the fluid lining the alveoli.
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surface tension
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The greater the _______ _______, the more work needed to spread the fluid out.
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air-liquid interface
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The surface tension of the lungs is caused by the __________ ________ formed by the thin layer of fluid lining the internal surface of the alveoli.
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fluid layer
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As the lung expands, so does the _______ ______ in the alveoli.
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work
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As the lungs expand, _____ is required not only to stretch the elastic tissue but also to increase the surface area of the fluid layer.
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decrease
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The surface tension acts to _________lung compliance.
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pulmonary surfactant
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a detergent like substance that decreases the surface tension in the alveoli.
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type II alveolar cells
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secretes pulmonary surfactant which are located in the walls of alveoli
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airway resistance
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the resistance of the entire system of airways in the respiratory tract
it is analogous w/ total peripheral resistance in cardiovascular physiology. |
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Airway resistance
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______ _________ is determined primarily by the resistancesof individual airways and is affected most strongly by changes in the airway radius.
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radius
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As _______ decreases, airway resistance increases.
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transpulmonary
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The increase in ____________ pressure that occurs during inspiration pulls outward on the airways, causing them to distend, which decreases resistance as inspiration continues.
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expiration
decreases |
During __________, the transpulmonary pressure _________, which reduces the distending force on airways and allows them to contract, thereby increasing the resistance.
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Sympathetic stimulation
bronchodilation Parasympathetic |
__________ stimulation causes relaxation of the smooth muscles and increases the radius of bronchioles (called ____________), whereas _____________stimulation causes contraction of the smooth muscle and bronchoconstriction.
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Epinephrine
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__________ released from the adrenal medulla during sympathetic stimulation also causes bronchodilation.
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Histamine
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__________ causes contraction of the smooth muscle, resulting in bronchoconstriction.
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