Respiratory biophysics Flashcards
In terms of pressure and volume what are the difference between heart and lungs?
The lungs increase the cavity and decrease the pressure, while the heart decreases the cavity and increase the pressure.
The pleural pressure is a negative pressure below the ____ pressure.
atmospheric pressure
The ______ inside the lungs is the driving force to inflate the lungs.
negative pressure
like a vaccum, sucks air in
mouth pressure___pleural pressure
mouth pressure > pleural pressure
Δ P = P ___ - P __
This increases the flow.
Δ P = P mouth - P alveoli
Elastic properties of the lung (recoil), will try to ___ the lungs so the ___ pressure balances it.
- colapse
- pleural
____ pressure is the driving force that balances the lungs’ elastic forces.
Pleural
Normal situation:
P bodysurface = P mouth = P atm
On ventilation:
P mouth __ P bodysurface
P mouth ≠ P bodysurface
P pleura ___ P alveoli
P pleura < P alveoli
Maximum elastic tension of the lung is at what moment of respiration?
Maximum inspired volume
Inspiration: Δ P __ 0
Expiration: Δ P __ 0
- Inspiration: Δ P > 0
- Expiration: Δ P < 0
Δ P = P mouth - P alveoli
Total R trachea ___ Total R alveoli
Total R trachea > Total R alveoli
Generation ____ have the highest R
5-15
The interphase between the air and the capillaries has a surface tension, this surface tension will make the alveoli tend to ____.
collapse
The _____ reduces the effect of the surface tension
Surfactant
Young LaPlace Law:
Δ P = 2 γ / r
γ = surface tension
r = radius
P alveoli pressure for inspiration is____.
-1cmH2O
P pleural pressure for inspiration is___
-6 to -10 cmH2O
P alveoli for expiration is
+1 cm H2O
P pleural for expiration is ___
- 3 to -5 cmH2O
Surface tension appears in any ____ between two ____.
- interphase
- fluids (eg: air & water)
Surface tension makes it seem as if there was an _____
elastic membrane
The force of surface tension is directly related with the ____ “elastic membrane” is streched.
length
F surface tension = γ ___
F surface tension = γ L