Red Blood Cells: Production and Function Flashcards
What nutrients do red blood cells require for their function?
Iron
Folate
Vit B12
EPO
What is the normal lifespan of RBCs?
120 days
How much Hb does each red blood cell contain?
640x10^6 molecules of Hb
What is haemoglobin made up of?
Haem containing Fe2+ and 4 globin polypeptide chains.
2 alpha subunits and 2 beta subunites
Where is Haem made?
Mitochondria
What conditions are caused by defects in globin?
Sickle cell anaemia
Thalassaemia
Where is erythropoietin produced?
In the kidneys
Where do red cell precursors develop?
In the Bone Marrow
What is nuclear maturation?
Chromatin condenses and is then extruded when RBC is maturing.
Cytoplasm then undergoes haemoglobinisation
What are the parts of the bone marrow where red blood cells are produced called?
Erythroid islands which are located radially. They are surrounded by macrophages which deliver iron to them from storage form (ferritin).
What happens to the colour of the RBC as it is undergoing its formation?
It goes from orthchromatic (many colours) to becoming red like the haemoglobin molecules it contains.
What are the stages of erythropoiesis called?
Proerythroblast
Basophilic normoblast
Polychromatic normoblast
Orthochromatic normoblast
Reticulocyte
RBC
What is RBC membrane composed of?
Phospholipids with proteins
What does haemoglobin do?
Transports O2 from lungs to tissues
Returns CO2 to the lungs
What are normal Hb levels in infants?
110 - 140 g/L
What are normal Hb levels in adult females?
115 - 155 g/L
What are normal Hb levels in adult males?
130 - 180 g/L
What is the normal RBC count?
3.8 - 6 x 10^12/L
What does Hb look like in normal adults?
Consists of 2 alpha and 2 non-alpha globin chains.
What chains does Hb contain in fetal and adult haemoglobin?
In fetal haemoglobin there are 2 gamma chains and 1 gamma chaina nd 1 beta chain. This is called haemoglobin F
At birth there is an increase in beta chains which start to replace gamma chains until adulthood where there are 2 alpha and 2 beta chains.
What chains can’t be made in thalassemia?
Beta chains
What is the stimulus for EPO release in the kidneys?
Renal O2 tension and hypoxia(anaemia or low atmospheric O2)