Gas transport in Blood (4) Flashcards
What is Henry’s law?
The amount of a given gas dissolve in a given type and volume of liquid (e.g blood) at a constant temperature is: proportional to the partial pressure of the gas in equilibrium within the liquid
What occurs if partial pressure in the gas phase is increased?
The concentration the gas in the liquid phase would increase proportionally
How is oxygen transported in the blood ?
- 5%- is bound to haemoglobin in red blood cells
1. 5%- in the dissolved form
How is oxygen transported by haemoglobin and describe its structure?
Haemoglobin can form reversible combination with O2 and each Hb molecule contains 4 haem groups and each group binds to one O2 molecule. If all haem groups are bonded, this is fully saturated.
What is the primary factor which determines the % saturation of haemoglobin with O2?
Partial pressure of oxygen ( PO2)
What is the O2 content of arterial blood determined by?
The haemoglobin concentration (Hb) and the saturation of Hb with O2 ( CaO2= 1.34 x (Hb) x SaO2
What can impair oxygen delivery to the tissues?
Respiratory disease, heart failure, or anaemia
What is co-operativty?
The binding of one O2 to Hb increase the affinity of Hb for O2
What is significant about the sigmoid structure of graph ?
The flat upper portions means that moderate fall in alveolar PO2 will not much affect oxygen loading
What is the Bohr effect?
The shift of the curve to the right which means increased release of O2 by conditions at the tissues and decreased affinity of haemoglobin for oxygen
How does foetal haemoglobin differ from adult haemoglobin in structure?
HbF (foetal) has 2 alpha and 2 gamma subunits and it interacts less with 2,3 - Biphsophateglycerate in red blood cells so HbF has a higher affinity for O2
What are the features of myoglobin?
Present in skeletal and cardiac muscles and there is 1 haem group per myoglobin molecule. There is no cooperative binding of oxygen and the dissociation curve is hyperbolic. It releases O2 at very low PO2 and provides a short term storage of O2 for anaerobic conditions
How do you calculate the oxygen delivery index (DO2L)?
DO2L= CaO2 x CI
CaO2- oxygen content of arterial blood
CI-cardiac index
How do you calculate oxygen content of arterial blood (CaO2)?
CaO2= 1.34 x (Hb) x SaO2
(Hb)- haemoglobin concentration
SaO2- %Hb saturation with O2
