Haematopoiesis

Question 1

How does protein formation help us to distinguish cells in the various stages of haemopoiesis?

Answer 1

Basis: As cells mature, they change from making lots of protein to making none.

Dispersed chromatin -> Clumped chromatin (nucleus)

Lots of nucleoli -> few

Lots of ribosomes (basophilic) -> few (acidophilic)

Question 2

Other than changes in protein formation, how do cells change as they mature?

Answer 2

Cells become smaller, immature cells are larger than their mature counterparts.

The nucleus is extruded, which means cell division stops.

Question 3

What are the stages of maturation in an RBC?

Answer 3

Haemocytoblast - pluripotent stem cell

Unipotent stem cell - common myeloid progenitor

Proerythroblast (nucleus is large, takes up most of the cell)

Basophilic erythroblast

Polychromatophilic erythroblast (nucleus condenses becomes smaller)

Orthochromatophilic erythroblast (nucleus still present but smaller)

Reticulocyte - remnants of ribosomes (no nucleus, stains a little more bluish due to ribosomes)

Erythrocytes - no nucleus (stains very pink since there are no ribosomes but lots of protein)

Question 4

What are the stages of maturation in an Granulocyte?

Answer 4

Haemocytoblast - pluripotent stem cell

Unipotent stem cell - common myeloid progenitor

Myeloblast - (large cell with blue staining cytoplasm, so looks like one big round nucleus)

Promyelocyte (Same but with granules)

Myelocyte

Metamyelocyte - will stain depending on their series(cell is smaller now, the size of a mature granulocyte but nucleus is still round)
Pink = eosinophilic
Blue = basophilic
Neutral = neutrophil

Band cell (Nucleus is now indented)

Mature (segmented) granulocyte (nucleus is now lobed and granules are prominent)

Question 5

What are the stages of maturation of a platelet?

Answer 5

Haemocytoblast - pluripotent stem cell

Unipotent stem cell - Myeloid progenitor

Megakaryoblast

Megakaryocyte

Platelets

Question 6

When does an RBC stop dividing?

Answer 6

When the mean cell Haemoglobin concentration is normal, cell division stops.

I.e. the concentration is normal

Question 7

What are the haematinics necessary for nucleus development?

Answer 7

Folate and vitamin B12

If either of these are deficient, the nucleus development is delayed.

Since red blood cells divide every time they develop, the nucleus must divide too, if you delay the nucleus developing, fewer divisions will occur, and the final RBC will be larger (Macrocytosis).

Question 8

What are the main dietary sources of iron?

Answer 8

Meat
Green leafy veg
Legumes
Fortified cereals
Yeast and yeast products
Oranges and fruit juice