Physiological
Adaptions to Hypoxia
•Reduced PIO2 reduces pressure
of O2 in blood: PaO2
•Brain triggers respiratory muscles to bring greater
volume of air into lungs with each
breath
•Hyperventilation- increase volume of air inspired per minute offsets decrease in air density
•# O2 molecules taken into lungs per minute is
nearly same as at sea level
•However, while quantity of O2 available in
lungs remains unchanged, PaO2 reduced as
elevation increases
•Reduced PaO2 haemoglobin binds less O2; less saturation of O2 in blood;
reduces O2 in blood