How heavy are the lungs
1kg
What is the surface area of the lungs
50 - 100m2
Describe surfactant
Wetting agent produced in the alveolar endothelium to reduce surface tension and increase lung compliance
Why is the conducting zone known as the anatomical dead space
No alveoli
What is a cut-off percentage for a ‘normal’ FVC/FEC1.0ratio?
80%
The body supply of O2 depends on
Concentration
Pressure
Air Composition of O2, N2, CO2
O2 = 20.93% N2 = 79.04% CO2 = 0.03%
Define Torr
- Torr: the pressure of air molecules that raises a column of mercury in a barometer to a height of 760 mm
Partial pressure computes as follows…
- Percentage concentration of a specific gas divided by total pressure of gas mixture
Partial pressure for O2, CO2, N2
Oxygen - 159
Carbon dioxide - 0.2
Nitrogen - 600
What is henrys law
The mass of a gas that dissolves in a fluid at a given temp varies in direct proportion to the pressure of the gas over the liquid
2 factor that govern the rate of gas diffusion into a fluid
- Pressure differential between the gas above the fluid and the gas dissolved in the fluid
Solubility of the gas in the fluid
What creates the driving force for gas exchange across the pulmonary membrane
Pressure difference between alveolar and pulmonary blood gases
amount of gas dissolved in a fluid equation
Quantity of gas = solubility coefficient x (gas partial pressure divided by total barometric pressure)
Gas exchange in the lungs is dependent on what
Pressure gradients
is CO2 highly soluble in plasma
Yes
Pulmonary blood volume increases by how much during intense exercise
3x
How much is the average PO2 in an extracellular and intracellular muscle cell
Extracellular - 40mm Hg
Intracellular - 46 mm Hg
3 steps in gas exchange in the tissues
- O2 diffuses to tissue
- Co2 diffuses to blood
- Blood returns to lungs
Functions of oxygen transported in physical solution
- Establishes the PO2 of the plasma and tissue fluids
- Helps to regulate breathing
Determines oxygen loading of hemoglobin in the lungs and subsequent release in tissues
- Helps to regulate breathing
What is the oxygen carrying capacity of hemoglobin for male and females
Men = 15g Hb/dL blood
- Women 14g Hb/dL blood
Define cooperative binding
The joining of O2 with hemoglobin
