Partial Pressure

partial pressure

portion of the total pressure exerted by the presence of a single molecule

total atmospheric pressure

760mmhHG

nitrogen

79%

20.95%

oxygen

0.038%

carbon dioxide

partial pressure

fraction x total pressure

water vapour

takes up fraction of air, displaces other molecules and lowers the patrial pressures of other gasses, takes from the 760

what happens to partial pressure of oxygen with increasing elevation

it decreases

movement of O2 and CO2 is always

from high partial pressure to low

what ensures rapid diffusion

short distance between air and red blood cells is very short

CO2 dissolves faster than oxygen

oxyhemoglobin dissociation curve

40 mmHG Po2 in tissues

when muscle becomes active, the partial pressure of tissue (norm 40) begins to drop so you obtain more oxygen from the blood

where is the highest PO2

The highest PO2 is in the air before breathing into the lungs

where is the lowest PO2

The lowest PO2 in the body is in the tissues, at the mitochondri

Respiratory Quotient

Carbon dioxide Production / Oxygen Consumption

Carbohydrates respiratory quotient

1.0

proteins respiratory quotient

0.8

fats respiratory quotient

0.7

If you are metabolizing
Carbohydrates (CHO) then
volume breathed

then
volume breathed in equals
volume breathed out

If you are metabolizing Fats
then volume

reathed in is
greater than volume
breathed out.

4 Steps to Movement of Oxygen

Ventilation

Lung Diffusion

Blood Transport

Tissue Diffusion

Ventilation

BULK

Blood Transport

BULK

Tissue Diffusion

DIFFUSION

Highest oxygen partial pressure

Alveoli in the lungs

Lowest oxygen partial pressure

Body tissues

Highest carbon dioxide partial pressure

Body tissues

Lowest carbon dioxide partial pressure

Alveoli in the lungs