Term
| What is the primary muscle of inspiration? |
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Definition
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Term
| What are the secondary muscles of inspiration? |
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Definition
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Term
| What are the tertiary/accessory muscles of inspiration? |
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Definition
| scalenes and the sternomastoids |
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Term
What is the primary muscle of expiration (in exercise)?
*Expiration is normally passive and requires no expiratory muscle effort |
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Definition
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Term
| What are the secondary muscles of expiration (during exercise)? |
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Definition
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Term
| What does it mean that the lung is a viscoelastic structure? |
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Definition
| it returns to its native shape after being deformed |
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Term
| If pressure outside the lung becomes more subatmospheric (negative pressure), will the lung volume increase or decrease? |
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Definition
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Term
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Definition
| It is a retardation of an effect when the forces acting upon a body are changed. In the lung, there is a difference in lung volumes at identical pressures during inflation and deflation as seen on the P-V loop. |
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Term
| How is a PV-loop for the lung constructed? |
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Definition
| lung is held STATIC (no air flow) and the pressure around the lung is brought more and more negative and then brought back to 0. |
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Term
| What is the Laplace equation for surface tension? |
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Definition
T = P x r
P = the pressure difference across the fluid interface, T is the surface tension (or wall tension), and r is the radius of the curvature |
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Term
| Would the surface tension of water be greater in a coffee mug or a swimming pool? |
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Definition
| The would be equal -- surface tension is independent of surface area |
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Term
| What is the surface tension equation for a sphere? |
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Definition
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Term
| Does pressure in a bubble increase or decrease with increasing radius? |
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Definition
| Pressure decreases as the radius increases |
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Term
| On the PV-loop graph, does inflation of the lungs with air or with saline exhibit more histeresis? |
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Definition
| Inflation of the lungs with air exhibits histeresis. Inflation with saline does not. |
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Term
| How is compliance calculated from a PV loop? |
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Definition
compliance = deltaV/deltaP
(slope of the graph) |
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Term
| Does an air-filled or a a saline-filled lung have a higher compliance? |
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Definition
| a saline-filled lung has a higher compliance and thus a steeper slope on the PV loop |
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Term
| Why is the inflation line for air inflation nearly flat until ~10 mmHg? |
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Definition
| the alveoli are initially ateclectic and therefore it takes a lot of pressure to pop the alveoli open |
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Term
| what is causing the difference between the graphs of the saline-filled and air-filled lungs? |
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Definition
| air-filled lungs have greater surface tension (histeresis is seen) whereas saline-filled lungs do not have surface tension (no histeresis) |
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Term
| What type of cell secretes pulmonary surfactant? |
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Definition
| alveolar type II pneumocytes |
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Term
| What is dipalmitoyl phosphatidyl-choline? |
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Definition
| it is a phospholipid that is the major constituent of pulmonary surfactant |
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Term
| why is it hard for babies who are born two months premature to breathe? |
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Definition
| surfactant is first synthesized at gestational age 7 months |
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Term
| Where is the intrapleural pressure (Ppl) in the lung the most negative? why? |
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Definition
| In the apex - the lungs pull down from itself which aids in inhalation |
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Term
| during cyclical breathing, does intrapleural pressure (Ppl) change more in the apex or base of the lung? |
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Definition
| Ppl is identical in both the base and the apex. |
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Term
| If the change in intrapleural pressure is identical in both the apex and the base, how does the base have a larger volume change? |
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Definition
| The base is more compliant |
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Term
| what is intrapleural pressure? |
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Definition
| pressure between the visceral and parietal pleura |
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Term
| what happens to the ventilation distribution when a person is breathing a volumes below FRC? |
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Definition
| the basal alveoli collapse in atelectasis |
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Term
| What is transpulmonary or translung pressure? |
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Definition
| it is the difference between the alveolar pressure and the intrapleural pressure in the lungs |
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Term
| why is normal intrapleural pressure subatmospheric compared to inside and outside of the lungs? |
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Definition
| the lung is being pulled both outward (by the chest cage) and inward (by the tendency of the lung to recoil) which decreases the pressure in the intrapleural space |
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Term
| what are various ways someone could get a pneumothorax? |
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Definition
-a hole in the chest wall
-a ruptured alveoli (a ventilator with a high pressure can do this) |
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Term
| how does the lung respond to a pneumothorax? |
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Definition
| The chest wall expands out and the lung shrinks in. The negative pressure in the intrapleural space is destroyed. |
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Term
| does the lung or the chest wall have a higher compliance? |
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Definition
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