Respiration Flashcards
Static transmural pressures
Difference between alveolar pressure and inter pleural pressure
What does compliance of the lung depend on and how?
Volume- low vol- high compliance
How does fibrosis effect compliance?
Same change in pressure results in small change in vol
How does emphysema effect compliance?
Same change in pressure results in big change in vol
How do emphysema and fibrosis effect FRC?
Emphysema- increase Fibrosis- decrease
Components of elastic recoil in the lungs
Elastic nature of cells, ECM and surface tension
What does Laplace’s equation mean in the lungs?
pressure in the larger sacs is lower the smaller sacs so air will flow into larger sacs from small causing them to collapse
Under laminar flow the movement of air in and out of lungs is proportional to what?
The pressure gradient and inversely proportional to the resistance
Equation for movement of air
V= change in pressure / resistance
Under turbulent conditions the rate of gas movement is proportional to what?
The square root of the pressure difference
What is Reynolds number?
2rvp/ n
What are the units for airway resistance?
cmH20.s.litres
What happens in emphysema?
Loss of elastic tissue and break down of alveolar wall, tethering between walls adjoining airspaces is reduced, flimsy airways
What is flow rate going up dependant on?
Dependant on effort
What is flow rate going down dependant on?
Not Dependant on effort