Flashcards in Normal Erythropoiesis Deck (67)
What are RBC's packed with?
What do RBC's NOT have?
No nucleus or mitochondria.
Also, no DNA/RNA
What does having no DNA/RNA mean?
There is no cell division
What is the life span of an RBC?
What is the role of the spleen in relation to RBC's?
It removes fragile old RBC’s from circulation
RBC's require constant ___________
Via what process does this constant replacement of RBC’s occur?
Where are new RBC's produced?
In red bone marrow
What are RBC's produced from?
Pluripotent stem cells
What engulf old RBC's?
Phagocytic cells of the liver and spleen
Outline the 2 main components of haemoglobin.
* Haem group – made of porphyrin ring, with iron group in the middle.
* Globin – globular protein, made up of amino acids.
What are globular haemoglobin proteins broken down to?
Amino acids which enter the blood stream
What is the haem group (minus iron) converted to?
What happens to bilirubin?
It is transported to the liver and secreted into bile.
- bilirubin products colour urine and faeces
What happens to iron from the haeme group?
It binds to transferrin in the blood and is recycled.
What is erythrocyte production regulated by?
The HORMONE erythropoietin (EPO).
Where is EPO produced?
In the kidney
What do cells in the kidney sense to increase the production of EPO?
Reduced oxygen-carrying capacity
Why is the fact that mature erythrocytes are shaped as a biconcave disc important?
* Diffusion distance minimised
* Surface area to volume ratio maximised
(This creates a large surface area : volume ratio, meaning more oxygen can get into the Hb effectively.)
What is the membrane of erythrocytes like?
Flexible – can deform to allow cells to squeeze in single file through capillaries
What % of the blood does plasma make up?
What is plasma?
The blood without cells, treated with anticoagulant
What are RBC ion balance and cell volume actively regulated by?
Energy-dependent Na+/K+ ATPases (‘the sodium pump’).
What is the only route for ATP synthesis in RBC’s?
Anaerobic glycolysis – RBC’s have no mitochondria
What is the key fuel in anaerobic glycolysis?
What state does iron have to be in to bind oxygen?
What keeps iron in its Fe2+ state? Why is this important?
NADH from glycolysis.
* methaemoglobin (HbFe3+) cannot bind O2
What is some glucose metabolised through?
The ‘hexose monophosphate shunt
What does the ‘hexose monophosphate shunt produce?
NADPH, required for maintenance of adequate levels of reduced GLUTATHIONE