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20 Cards in this Set
- Front
- Back
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What prevents lungs from collapsing?
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The pressue differntial between the intrapleural space and the lungs
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negative-pressure breathing
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increase in volume reduces intrapleural pressue causing lungs to expand and fill with air in a vaccum-like fashion
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external intercostal muscles
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- contract during inhalation and pushes rib cage and chest wall up and out
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exhalation
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passive process
- decrease in thoracic cavity volume causes air pressue in the interpleural space to increase |
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internal intercostal muscles
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- contract, pulling rib cage down during FORCED exhalation
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surfactant
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surrounds alveoli
- reduces high surface tension of fluid lining the alveoli, preventing alveolar collapse during exhalation |
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medulla oblongata
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- respiratory center
- stimulate intercostal uscles or diaphragm to contract |
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chemotreceptors
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- found in aorta, etc.
- respond to changes in pH and pCO2 in blood stimulating medulla oblongata |
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Ventiliation is consciously controlled by that part of the brain?
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cerebrum
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Hyperventilation
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- deep, rapid breathing
- lowers pCO2 in blood below normal - chemotreceptors sense this and signal medulla oblongata to inhibit breathing |
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vital capacity
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= mad amount of air that can forcibly be inhaled and exhaled from lungs
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tidal volume
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- amount o fair normally inhaled and exhaled with each breath
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residual volume
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- air that always remains in lungs, preventing alveoli from collapsing
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expiratory reserve volume
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- volume of air that can still be forcibly exhaled following normal exhalation
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total lung capacity
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- equal to the vital capacity + residual volume
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In what three ways does the body compensate for high altitudes?
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- increase ventilation (hyperventilation)
- increase RBCs (polycythemia) - decrease affinity of O2 to facilitate unloading of oxygen in the TISSUES |
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Why is the process of inhalation referred to as negative-pressure breathing?
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- expansion of thoracic cavity creates a vacuum, which pulls air into lungs
- contrasts positive-pressure breathing: air is forced into lungs |
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The lungs can collapse from...
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- insufficient surfactant production
- rupture of parietal pleura |
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What is the function of surfactant, and where is it found?
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- Surfactant is secreted by eptithelial cells in lung and coats alveli
- reduces alveolar suface tension - makes lungs easier to inflate during inhalation - prevents alveolar collapse during exhalation |
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Sequence of passages air travels through during inhalation
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pharynx --> larynx --> trachea --> bronchi --> alveoli
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