Erythropoesis

Question 1

Erythrocyte production is regulated by what?

Answer 1

By EPO from the kidneys. (Released in response to a reduced oxygen carrying capacity)

Question 2

RBCs have no mitochondria, so what is their route of ATP synthesis?

Answer 2

Anaerobic glycolysis (glucose is the key fuel)

Question 3

What compound made from glycolysis helps to keep iron in the Fe2+ state?

Answer 3

NADH

Note (HbFe3+ cannot bind oxygen)

Question 4

Some glucose is metabolised through the hexose monophosphatase shunt, this produces what?

Answer 4

This produces NADPH which is required for maintenance of adequate levels of reduced glutathione.

Question 5

What compound is produced when O2 is low

Answer 5

2,3 BPG, (releases oxygen from haemoglobin)

Question 6

What compound combat oxidative stress?

Answer 6

Reduced glutathione.

Question 7

A word on the importance of glutathione…

Answer 7

Reduced glutathione is essential to detoxify hydrogen peroxide (the primary intermediate in oxidative damage)

NADPH from the penthouse phosphate pathway is needed to produce reduced glutathione.

In RBCs, lack of reduced glutathione (as a consequence of G6PD insufficiency, can lead to cell damage)

Question 8

How is the majority of carbon dioxide transported?

Answer 8

60% is transported as bicarbonate (HCO3), facilitate by carbonic anyhydrase.

Question 9

What is adult haemoglobin composed of?

Answer 9

4 globin sub units.

4 Haem molecules (each haem group contains a single Fe2+ ion)

Each haem group can bind one oxygen molecule.

Question 10

Adult haemoglobin is predominantly what?

Answer 10

Alpha2 Beta 2

Question 11

The oxygen Hb dissociation curve is shifted in what direction by the presence of 2,3 BPG?

Answer 11

2,3 BPG is a small molecule that has a high affinity for oxygen.

2,3 BPG causes the curve to shift to the right.(so that less Hb is bound to oxygen)

Question 12

What are the 3 granulocytes?

Answer 12

Basophils
Eosinophils
Neutrophils

ALL come from the common myeloid progenitor.

Question 13

If the MCV is low (microcytic), consider problems with what?

Answer 13

Consider problems with haemoglobinisation.

Question 14

If MCV high (macrocytic), consider problems wiith what?

Answer 14

With maturation.

Question 15

To make Hb you need what?

Answer 15

• Globins
• Haem (porphyrin ring, Fe2+)

Shortage in these results in microcytic, hypochromiic cells.

Question 16

Hypochromic microcytic anaemia = defective Hb synthesis which is a cytoplasmic defect.

Answer 16

…