Two types of gas movement

barometric pressure

Oxygen diffusion gradient

Transit time
about 0.75 seconds

Time for capillary plasma P02 to = alveolar P02
1/3 the time it takes to move through a capillary

Diffusion capacity
affected by hematocrit and pulmonary blood volume

O2 + hemoglobin?
rapid and reversible binding

Most common form of bound 02 in blood
otherwise 2% is dissolved in plasma

Where 02 binds with hemoglobin

Where 02 is released from hemoglobin

oxygen saturation
compared with the capacity to bind

P50

Normal P50 levels (in mmHg)

Oxyhemoglobin curve shifts left
less unloading of 02 at tissue level

Oxyhemoglobin curve shifts right
more unloading of 02 at tissue level

2,3 DPG
found in red blood cells, causes right curve shift

Decrease in pH, increase in CO2

Exercise effect on curve
makes 02 readily available for muscle in the plasma

Pa02
measures free 02 molecules in plasma, doesn't measure 02 bound by HGB

Sa02
in arterial blood

Ca02
only measure that incorporates amount of hemoglobin

210 greater affinity for HGB than 02
odorless and colorless, makes blood bright red, no cyanosis

Most common way CO2 is carried in blood
60%. Other ways are plasma (10%) and carbamino protein (30%)

Carbonic acid and pH
able to rapidly release or bind H+

Normal pH range

Normal Ca02 level

Pa02

Hypercapnia
levels above 48

Normal Va/Q ratio

What ventilation and perfusion should be in lungs

Leads to lower Va/Q ratio
one section of airway is not properly ventilated, blood is not getting perfused adequately

Two causes of diffusion block
decreased permeability across alveolar membrane