Red Cells, Haemoglobin and intro to Anaemia

Question 1

Red cell shape and what this shape allows

Answer 1

Discoid shape, 7um

Allows flexibility and increased SA for gas exchange

Question 2

Red cell unique shape and deformability

Answer 2

Allows gas exchange and movement through small capillaries.
determined by lipid bilayer and cytoskeletal proteins (spectrin, actin, ankyrin)
thus a mutation of these, deformed, more rigid RBC’s, shortened lifespan

Question 3

how does Red cell keeps Hb in reduced state, and maintains osmotic equilibrium

_____ pathway creating ____ (____ equilibrium)
_____ shunt produces _____, keeps Hb reduced

Defects cause ______ (_____ deficiency)

Answer 3

Glycolytic pathway creating ATP (osotic equilibrium)
HMP shunt produces NADPH, keeps Hb reduced

Defects cause haemolysis (G6PD deficiency)

Question 4

Red cell Hb and gas exchange.

Defect in globin? Low iron?

Answer 4

Predominant Hb is HbA, 2 alpha and beta chains plus haem group.
Defect in globin is thalassaemia, low iron means low haeme

Question 5

Erythroid development

____ multilineage. ___ to _____to ____. Responds to _____
Then _____, _____ erythroblast , ______ erythroblast, ____ erythroblast, _____, mature red cell

Answer 5

myeloid multilineage. HSC to BFU-E to CFU-E. Responds to erythropoetin
Then Proerythroblast, basophilic erythroblast, polychromatic erythroblast, pyknoticerythroblast, reticuocyte, mature red cell. (loosely pro, normo, retic, mature)

*replace erythroblast with normoblast

Question 6

Hypoxia driving erythropoiesis

Answer 6

HF-1 alpha and beta drive erythropoieses, angiogenenisis and upregulate red cell transferrin receptor

Question 7

What changes occur during red cell differentiation

Answer 7

Increased Hb
Chromatin clumping, extrude nucleus
loss of RNA.
Means reticulocytes seen in blood with blood loss, haemolysis. Low in bone marrow failure

Question 8

Requirements for red cell production

Answer 8

iron, folate, B12

Question 9

Erythropoiesis regulation

Answer 9

RBC life span is 120 days, and is regulated by erythropoietin
A gylcoprotein made in the kidney in response to low O2, low atmospheriv

Question 10

Effects of erythropoietin

Answer 10

increases RBC production by: stimulatingBFU- and CFU-E + pronormoblast
increases Hb synthesis
reduces rbc maturation time
increased reticulocyte release

by jak pathway

Question 11

Kinetics of erythropoiesis

Answer 11

One proerythroblast leads to 16 red cells. This takes 7-10 days, maturation takes 2 days

Question 12

Clinical implications of erythropoietin

Answer 12

Renal failure: low Hb

Can use Epo (recombinant) when there is anaemia of renal failure, other anaemias. Use for potential abuse

Question 13

things that will alter epo release

Answer 13

Atmospheric O2
O2 dissociation curve
Cardiopulmonary function
Hb concentration
renal circulation (if low, high Hb, rbc's)

Question 14

Red cell reporting

Answer 14

Haematocrit, Hb conentration. Frcation of blood volume occupied by red cells. (.41-.5 and .36-.44)

NB high Hb/ rbc’s is polycythemia

Question 15

Hb levels through life

Answer 15

Neonates hgh, plummets to just below 100 as childen. Women plateauat 110-130 g/L. Men at 130-140.

Any lowered Hb is likely got a cause

Question 16

Reticulocyte counts

Answer 16

Count raises secondary to epo
After acute haemorrhage, levels raise, and Hb does over 6-10 days.
If there is no increase, suggests marrow function lacking or lack of epo stimulus

Question 17

Factors that impair reticulocyte response

Answer 17

Marrow disease: Iron, vit B12 and folate deficiency
Lack of epo
Ineffective erythropoiesis such as thalassaemia, myelodysplastic syndrome
Chronic inflammation, malignancy

Question 18

Red cell destruction

Answer 18

120 days
Cells less defomrable, removed in spleen
releases Hb, whichis broken down into globin and haem.
Haem to iron, to transferrin back to red cell
Protopophyrin to bilirubin, liver to bile