Red cell Physiology

Question 1

Describe the process of a red cell being created?

Answer 1

Haemotocytoblast (stem cell)

• -> Proerythroblast (committed cell)
• -> ribosome synthesis: Erythroblast (early/late)
• ->Normoblast
• -> Reticulocyte (released into blood)
• -> Erythrocyte

Question 2

What substances are used to make RBCs?

Answer 2

Metals:
Vitamins
Amino acids
Hormones

Question 3

What metals are required for RBCs?

Answer 3

IRON

Also copper, cobalt &manganese

Question 4

What vitamins are required to make RBCs?

Answer 4

B12 & FOLIC ACID

Also thiamine, B6, C & E

Question 5

What hormones are essential to RBC development?

Answer 5

ERYTHROPOIETIN

Also Gm-CSF, Androgens, thyroxine

Question 6

What cell breaks down RBCs?

Answer 6

Macrophages in the reticuloendothelial system tissues i.e. spleen, liver, lymph nodes etc

Question 7

What becomes of haemoglobin after a RBC is broken down?

Answer 7

Globin –> Amino acids (recycled)

Haem –> Iron (recycled) & Bilirubin (excreted)

Question 8

How does iron enter from the gut?

Answer 8

Bound to enterocytes (most ends up in your shit) and transported to the plasma by ferroportin protein

Question 9

What happens to Fe once it enters circulation?

Answer 9

Transported around by transferrin

Then it’s stored in tissues as ferritin

Question 10

What does Hepcidin do?

Answer 10

Blocks ferroportin –> decreased iron absorption

It’s produced by hepatocytes in response to inflammation

Question 11

What factors can lower haemoglobin affinity for O2?

Answer 11

Bohr effect
Acidosis- high H+
Hyperythermia
Higher DPG
Hypercapnia- high C02

Question 12

What makes up a normal adult haemoglobin (HbA)?

Answer 12

1 Haem Molecule
2 Alpha globin chains
2 Beta globin chains

Question 13

what are the phases of RBC development

Answer 13

• Stem cell
• Committed cell
• Development pathway :
  phase 1: ribosome synthesis
  phase 2: haemoglobin accumulation
  phase 3: ejection of nucleus

Question 14

What does a shift to the right in oxyhemoglobin graph indicate?

Answer 14

Increased dissociation

Question 15

What does a shift to the left in oxyhemoglobin graph indicate?

Answer 15

Decreased dissociation

Question 16

What does glucose 6 phosphate dehydrogenase do?

Answer 16

Protects red cell proteins (Haemoglobin) from oxidative damage
–Produces NADPH - Vital for reduction of glutathione
–Reduced glutathione scavenges and detoxifies reactive oxygen species