Gas Transport 1 Flashcards
What is Henry’s law
The amount of a given gas dissolve in a given type and volume of liquid at a constant temp is
Proportional to a pp of the gas in equilibrium with the liquid
What does Henry’s law mean in relation to a gas pp
Means if pp in gas phase increased conc of gas in liquid phase would increase proportionally
The pp of a gas in sol is
It’s pp in gas mix with it is in equilibrium
Under resting conditions dissolved oxygen is taken up in tissues by
Dos solved oxygen
15ml/min
What at strenuous exercise oxygen taken up as
Dissolved
90ml/min
What is the resting consumption of body cells for oxygen
250ml/min
What happens to oxygen consumption with strenuous exercise
Increase 25 fold
How is oxygen mostly transported in the blood
Bound to Hb
What is normal Po2 arterial
13.3 kPa
What is a normal Hb conc
15 grams/100ml
What are the two present forms of oxygen in the blood
Bound to Hb
Physically dos solved
What is the interaction between Hb nd oxygen
Reversible combination
Hb has 4 haem groups which each bunds an oxygen
Hb fully saturated when oxygen binds
What is the primary factor which determine the percent saturation of Hb with oxygen
Po2
What is the oxygen delivery index
DO2I = CaO2 x C
CaO2 - oxygen content arterial blood
CI - cardiac index
Oxygen delivery to tissues is a function of
Oxygen content of arterial blood and the cardiac output
How do u work out the oxygen content of arterial blood
CaO2 = 1.34 x Hb x SaO2
1.34 - one gram Hb can carry this much oxygen when fully saturated
SaO2 - percent Hb saturated with oxygen (determined by Po2)
What can impair oxygen delivery to the tissue
RESP disease
Heart failure
Anaemia
What does binding oxygen to Hb do
Increases the affinity of Hb for oxygen for
Cooperatively and sigmoid
What is the significance of sigmoid
Flat upper portions meads there is a moderate fall in alv po2 and will not affect oxygen loading
Steep loser part - tissues get lot of oxygen for a small drop in capillary po2
What is the Bohr effect
When the Hb and oxygen curve of spdissociatikn shift to the right
Increased release oxygen by conditions at the tissue
What is foetal Hb
HbF differs as has 2 alpha and 2 gamma subunits
Interacts less with 2,3- biphosphoglcerate in RBC
HbF has a higher affinity for oxygen
So dissociation curve shift to left
Allow oxygen to move form mother to foetus even is po2 low
Where is myoglobin present
Skeletal and cardiac muscle
What does myoglobin have and do
Has one haem group per mol No coop binding with oxygen Dissociation curve hyperbolic Myoglobin releases oxygen at low po2 Short time storage for oxygen for anaerobic conditions If in tissue indicate muscle damage
