gaseous exchange Flashcards
diffusion
net movement of particles from an area of high partial pressure to an area of low partial pressure across a concentration gradient
qualities of diffusion rate during exercise
quicker and more efficient due to a steeper gradient as muscles are using and producing more O2 and CO2
diffusion gradient
the difference in areas of pressure (or concentration) from one side of a membrane to the other
partial pressure
the pressure exerted by an individual gas held in a mixture of gases
external respiration
exchange of gases in the lungs and between the capillaries wrapped around alveoli
external respiration: movement of oxygen
moves from high Pp of 105 in alveoli to low Pp of 40 in the capillaries, haemoglobin associates with oxygen to form oxyhaemoglobin
external respiration: movement of CO2
moves from a high Pp of 46 in carbon-rich blood to a low Pp of 40 in the alveoli down the diffusion gradient
association
when O2 combines with haemoglobin through diffusion at the lungs to produce oxyhaemoglobin
saturation
the amount of O2 combined with haemoglobin usually expressed as a % and depends on the ppO2
dissociation
when O2 is released from the haemoglobin through diffusion at the muscles
oxyhaemoglobin dissociation curve
shows the relationship between ppO2 and the % saturation of haemoglobin
- 25% of O2 is dissociated at the muscle during rest
conditions of release: O2 and body temp
- more O2 is used so there is a steeper diffusion gradient causing more O2 to dissociate
- body temp increases which makes O2 dissociate from haemoglobin more readily
conditions of release: CO2 and acidity
- muscles produce more CO2 therefore there is a steeper gradient so more CO2 diffuses into blood
- lactic acid and carbonic acid increase acidity which makes O2 dissociate more readily
the Bohr shift
when an increase in acidity causes the oxyhaemoglobin curve to shift right
