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13 Cards in this Set
- Front
- Back
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Which muscles are responsible for vertical and horizontal increase during inspiration?
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Inspiration:
@ rest: diaphragm (vertical) external intercoastals (horizontal) @active: <same> |
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Which muscles are responsible for vertical and horizontal increase during expiration?
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expiration:
@ rest: passive elastic stretch (vertical and horizontal) @active: abdominal muscles (vertical) internal intercoastals (horizontal) |
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Type of receptors in lungs?
What binds to them, and result? An antagonist, and result? |
B2 receptors.
Nor/epi → vasodilation (VD) Histamine → VC |
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What equation describes the air flow in and out of alveoli?
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Q = ∆P / R
where Q is air flow, and P = Palv - Patm |
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What determines whether air enters the alveoli, or leaves?
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Air enters when the lungs expand, causing Palv < Patm.
Air leaves when the lungs contract, causing Palv > Patm. |
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List factors that the extent of lung volume depends on.
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1. Transpulmonary pressure
2. Lung compliance |
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What is transpulmonary pressure?
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A value that is relative to lung volume, given by TP = Palv - Pip, where Pip is the interplueral pressure.
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How does the value of Pip relate to lung expansion or contraction within the transpulmonary pressure equation?
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The more neg Pip becomes, the greater the TP, and the more the lungs expand.
The less negative Pip becomes, the lower the TP, and the lungs contract. |
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When is Pip positive?
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During pneumothorax (collapsed lungs)
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What is the equation for lung compliance?
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C = ∆V / ∆(Palv - Pip)
When C is lower, ∆V is lower. |
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What are the determinants of lung compliance?
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1. Elasticity of alveoli.
2. Surface tension in alveoli. |
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How does surfact tension relate to compliance?
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The pressure (P) on alveoli opposes compliance according to:
P = 2T / radius where T is surface tension. The lower the T, the lower the P and more compliant the alveoli are. |
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What reduces the air/water surface tension of alveoli?
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Surfactant
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