Session 3 -Oxygen Dissociation Flashcards
What are the 2 oxygen binding pigments
Haemoglobin and myoglobin
How many oxygen molecules each do haemoglobin and myoglobin bind
Myoglobin binds 1
Haemoglobin binds 1
Where is myoglobin found
Muscles
What do dissociation curves show and explain this relationship
Relation between partial pressure of oxygen and the amount of oxygen bound
- as the oxygen is diffused most of it goes into circulation ad binds onto haemoglobin molecules, when this is “full” the rest of the diffused oxygen dissolves into the arterial blood and saturates cuz amount of pigment is limited
Why does binding of haem and oxygen saturate above a certain po2 value
Amount of o2 bound depends on amount of pigment, when fully bound eventually dissolves into arterial blood
Show percent of oxygen bound and pigment concentration independent of each other
How do you calculate how much oxygen has been given up when changing between partial pressures
Work out difference in percentage saturation between the 2 po2 values
Take amount bound at full saturation and use percentage to calc how much given up
What are the 2 ‘moods’ for haemoglobin
Low affinity (difficult for oxygen to bind) is called T state (tense)
High affinity (easy for oxygen to bind) is called R state (relaxed)
Describe the chain of events that happens when po2 is low
Makes it difficult for first oxygen to bind as it is in tense state, then eases up as more binding occurs
Describe how a sigmoid always curve is achieved in relation to the haemoglobin dissociation curve
Initial relationship is shallow as haemoglobin is tense due to low po2 but as more binding occurs po2 rises and gives the graph a steeper look (where saturation change greatly)
Flattens when 100% saturation is reached giving the graph a SIGMOIDAL curve
Reaction reversible depending on po2 levels ( low o2, not as relaxed)
