Red Blood Cells Flashcards
What do all blood cells originate from?
Haematopoetic stem cells
Where does foetal haematopoeisis start?
The yolk sac
Which bones in children does haematopoiesis occur in?
All bones
Which bones in adults does haematopoiesis occur in?
Long bones - femur, pelvis, sternum
What are the two characteristics of HSC?
The can self renew and they can differentiate
What are the two cells that HSC differentiate into?
Common Lymphoid Progenitor and Common Myeloid Progenitor
What is the intravascular life span of red blood cells?
120 days
Where does erythropoiesis occur?
Bone Marrow
What is HAEM iron also known as?
Ferrous iron - fe2+
What is non-HAEM iron also known as?
Ferric iron - fe3+
What affect do phytates have on iron absorption?
They reduce it
What organs is excess iron toxic to?
Heart and liver
Where is ferroportin found?
In duodenum enterocytes
How do we lose iron if it is high?
Higher iron leads to HEPCIDIN release, which blocks ferroportin, so iron cannot leave the enterocytes. Therefore when the enterocyte is destroyed so is the iron stored within it
What does inflammation do to Hepcidin?
Increases hepcidin, and therefore can lead to anaemia of inflammation as there is not enough iron in the blood as it is all being kept within the enterocytes
Why do we need Folate and Vitamin B12?
They are needed for dTTP synthesis - thymidine, needed for DNA synthesis
What can a Vitamin B12 and Folate deficiency cause?
Megaloblastic erythropoiesis - this is because the cells keep dividing but lack the DNA
Name three sources of Folate
Green leafy vegetables, cauliflower and Brussels sprouts
Name three sources of B12
Meat, fish, clams
What does B12 combine with so it can be absorbed?
Intrinsic factor which is made in the gastric parietal cells
What causes vitamin B12 deficiency
Inadequate intake, pernicious anaemia and malabsorption
What is pernicious anaemia?
This is where your body does not make IF therefore the B12 cannot bind and therefore cannot be absorbed
Why do red blood cells have a life span of 120 days?
When they move through capillaries and blood vessels, the walls bend and stretch meaning they get damaged
Where are the red blood cells destroyed?
Spleen
What are the RBCs broken down into?
HAEM and globin
What does the HAEM part of the RBC after it is destroyed?
Gets broken down into bilirubin
How is bilirubin excreted
In bile
Why is bile important
Contains bile salts which are needed for the emulsification of fats so they can be absorbed