Physics of Oxygen Flashcards
Conversion
1 atm=
760 mmHg
1034 cm H2O
- 3 kPa
- 7 psi
pressure
force applied per unit area
Barometric pressure
pressure that is exerted by earth’s atmosphere
partial pressure
In a mixed gas, each gas has a partial pressure it exerts
- pressure is the same as it is alone in the same chamber at the same temperature
Dalton’s law
The sum of all partial pressure
Sea level proportion of abundant gases in the atmosphere
79% N2, 21% O2, 0.03% CO2
Critical Temperature
Max temperature a vapour can revert back to liquid by increasing pressure
Ideal Alveolar Gas Equation
PAO2= (PB-47)FiO2- (PaCO2/0.8) PAO2= alveolar O2 tension PB= barometric pressure 47= water vapour tension FiO2: fraction of inspired O2 PaCO2: arterial CO2 tension
Volume coversions
1L= 10cm^3 1m^3= 1000L 1L= 1000mL
Kinetic energy
- available energy to do work
- energy an object possesses while it is in motion
Evaporation/ Factors that increase rate of evaporation/ Forces to overcome
- evaporation can occur any T above freezing point
Factors: - Increase in kinetic energy
- Increase in surface area of the liquid
- Decrease in pressure above or around the liquid
Forces to overcome:
- attraction of the molecules for each other
- pressure of the gas above the liquid
Condensation
Gas to liquid
Critical Pressure
The pressure required for a sustance to maintain EQ at critical temperature.
Rate of evaporation and condensation is the same
Boyle’s Law
Constant T; P is inversely proportional to V
V1P1=V2P2
Charles’s Law
V increases with T at constant P
V1/T1=V2/T2
Gay-Lusac’s Law/ Amonton’s Law
Constant V; the pressure gas exerts rises as the temperature of the gas rises
P1/T1=P2/T2
Ideal Gas Law
PV=nRT==> (P1V1)/T1=(P2V2)/T2
- assuming moles are constant
Diffusion
movement of molecules from high concentration to low concentration
Graham’s law
When two gases at the same temperature and pressure will diffuse at a rate inversely proportional to the square root of ther masses
Rate1/Rate2= (M2M1)^(1/2)
Henry’s Law/ Solubility coeffiecients
amount of gas that can dissolve is proportional to the partial pressure of the gas of the liquid
in plasma at 37C
- 0.023mL O2/mL of blood /760mmHg PpO2
- 0.510 mL CO2/mL of blood /760 mHg PpCO2
Fick’s Law
proportional to SA, pressure gradient
inversely proportional to thickness of the membrane
V = Area* Diffusion constant (P1-P2) /Thickness
laminar
flow in discrete layers or streamlines
occurs in smooth uniform tubes
turbulent
chaotic movement
Transitional flow
mix of laminar and turbulent
Poiseuille’s Law
gas flow is dependent of pressure pushing of fluid through tube and resistance.
Resistance
R= (8nl)/(PiR^4) n= viscosity l= length of tube r= radius of tube
Poiseuille’s formula
(dP)= Q*R ==> R=dP/Q
R= resistance
Q= flow
units cmH2O/L/s
can be writen as: Q=dPr^4pi/8ln
Bernouilli’s Principle
increased in the speed simultaneously with a decrease in pressure
Venturi Effect
reduction in pressure that results when a fluid flows through a constricted section of pipe
Coanda effect
a jet flow attaches itself to a nearby surface and remains attached even when the surface curves away from the initial jet direction
Factors that increase flow
- increase in pressure
- increase in radius
- shorter length of tube
- decrease in viscosity of fluid
