Hb and Thalassaemia Flashcards
What is on the x and y axis of the Hb dissociation curve?
x = ppO2 y = HbO2(%)
How does a left/ right shift of the O2 dissociation curve describe a change in affinity for oxygen?
Left = higher affinity Right = lower affinity
Recall 5 factors that affect the position of the O2 dissociation curve
[2,3-DPG] pH [CO2] %HbS %HbF
Which direction does the O2 dissociation curve move in when the concentration of 2,3-DPG increases?
right
Describe the effect of HbS/ HbF on the position of the oxygen dissociation curve
HbS increase –> right
HbF increase –> left
What is the normal concentration of Hb in adults?
120-165g/L
What mass of iron is contained within one gram of Hb?
3.4mg
Recall the structure of haem
Protoporphyrin ring + central iron (usually ferrous)
Where is haem synthesised and what enzyme is used?
Mitochondria - ALAS
How many amino acids are in an alpha globin chain?
141
How many amino acids are in a non-alpha globin chain?
146
Recall the location and arrangement of the globin genes
Arrangement: 2 clusters - alpha = 2 x alpha and an epsilon gene, beta = beta, gamma and delta globin genes
Location: alpha = c16, beta = c11
What globin chains make up foetal Hb?
alpha and gamma
What is the normal adult concentration of erythrocytes?
3.5-5x10^12/ L
When is Hb synthesised?
During development of erythrocyte: begins in pro-erythroblast stage and completed in reticulocyte stage