Normal erythropoiesis Flashcards
What are the properties of mature RBC’s?
Packed with Hb
No nuclues, mitochondria nor DNA/RNA
How long does a RBC live for?
~120 days
What removes old RBC’s from circulation?
Spleen
What is the name for the replacement of RBC’s?
Erythropoiesis
What happens to old RBC’s?
Phagocytic cells of liver and spleen engulf them
Globular haemoglobin is broken down to amino acids which enter blood stream
Haem (minus iron) converted to biliruben
Iron binds to transferrin in the blood and is recycled
Biliruben breakdown colours urine and faeces
What stimulates RBC production by bone marrow?
Erythropoieten (EPO) released by the kidney
What are the shape and sizes of mature erythrocytes?
Biconcave discs
8um diameter
2um thick at edge
1um thick in centre
What helps keep iron in the Fe2+ state?
NADH
Can methaemoglobin (HbFe3+) bind to O2?
No
What reduced levels of glutathione?
NADPH, produced by glucose metabolised through hexose monophosphate shunt
How is 2,3,bisophosphoglycerate formed (2,3,BPG)?
When Po2 is reduced
Describe glutathione?
Tripeptide, consisting of glutamate, cysteine and glycine
What does reduced glutathione do?
Combats oxidative stress
What are the 3 forms that CO2 can be carried to the lungs?
- Physically dissolved in solution (10%)
- Bound to Hb (30%)
- As bicarbonate ion (60%)
How many globin sub-units of protein make up haemoglobin?
4
