Haematopoiesis

Question 1

What is haematopoiesis

Answer 1

It is the production of circulating blood cells from the bone marrow

Question 2

Life span of granulocytes

Answer 2

<48hrs

Question 3

Concentration of granulocytes in the blood

Answer 3

2-8x10^9

Question 4

Life span of erythrocytes

Answer 4

120 days

Question 5

Concentration in the blood

Answer 5

5x10^12/L

Question 6

Life span of platelets

Answer 6

7-10days

Question 7

Concentration of platelets

Answer 7

150-450x10^9/L

Question 8

Lifespan of monocytes

Answer 8

Days to weeks depending on differentiation. Some tissue macrophages may last years

Question 9

Concentration of macrophages in the blood

Answer 9

0.5x10^9/L

Question 10

Lifespan of lymphocytes

Answer 10

Days to years depending on whether naive or memory

Question 11

Concentration of lymphocytes

Answer 11

1-4x10/L

Question 12

What is immunophenotyping

Answer 12

Look for specific markers or proteins found on the cell surface or inside the cell DNA be performed on blood or bone marrow looking for a specific cell type

Question 13

What does the marker CD34 identify and why is it used

Answer 13

It identifies a subset of marrow cells including HSCs only small numbers are usually present in the blood but the number is increased when recovering from damage inflicted by cytotoxic drugs following administration of G-CSF for stem cell harvesting for transplant
Helps to identify these cells

Question 14

Where does haematopoiesis occur in the fetus

Answer 14

Extra embryonic yolk sac
Aorta-gonad-mesonsephros
Liver
Bone marrow

Question 15

What day does haematopoiesis start in the fetus

Answer 15

Day 17

Question 16

Where does haematopoiesis occur in the adult

Answer 16

Bone marrow 
Red and yellow marrow 
Active bone marrow is in the red marrow 
Yellow marrow is adipocytes 
The marrow is found in the medullary cavity - space enclosed by the cortex and traversed by trabeculae

Question 17

When can haematopoiesis occur in other sites a d what sites are those

Answer 17

Liver and spleen

Condition called extra medullary haematopoiesis occurs in certain pathologies myelofibrosis or untreated thalassaemia

Question 18

Cell fate choices of a HSC in haematopoiesis

Answer 18

Quiescence, self renewal, differentiation

Question 19

Progenitor cell fate choices

Answer 19

Proliferation, lineage commitment, terminal differentiation

Question 20

What doe progenitor cells require in order to differentiate into their terminal cell

Answer 20

Intrinsic factors- lineage determining TF and their epigenetic regulation
Extrinsic regulators - both cellular an soluble growth factors found in the bone marrow micro environment. These factors are up and down regulated according to certain stimuli.

Question 21

Where can the cellular elements be found

Answer 21

Bone marrow stroma

- surrounding bone, network of vascular channels and sinusoids, fat cells, fibrocytes, and extracellular Maria

Question 22

Bone marrow testing samples are taken from where

Answer 22

Iliac crest

Question 23

What types of assessment of haematopoiesis are there and what do they assess

Answer 23

Bone marrow trephine
Core of BM and is used to examine the overall cellularity and architecture of bone marrow and ECM components
Bone marrow aspirate used to assess morphology/numbers of HSC at different t stages and identify abnormal infiltrates

Question 24

What is the commonly used term for early progenitor cells

Answer 24

Blast

Question 25

Platelet progenitor cells

Answer 25

Megakaryoblast | Megakaryocyte

Question 26

What is platelet production regulated by

Answer 26

TPO Throbopoietin Produced by the liver

Question 27

In what instances are platelets transfused and how long do they last

Answer 27

Chemotherapy | 1-5 days

Question 28

When is it futile to infuse platelets

Answer 28

Immune Thrombocytopenia | Only last few hours due to ab against them and spleen clearance

Question 29

What regulates granulocytes and monocytes production

Answer 29

G-CSF | GM-CSF

Question 30

What are precursors names for granulocytes and monocytes

Answer 30

Promyelocytes Promonocytes They have identifiable lineage specific granules that stain - MPO for neutrophil lineage At the granulocyctic lineage myelocyte stage cells acquire distinctive lysosomal enzymes and other granules required for function

Question 31

Mature granulocytes features

Answer 31

Lost chromaitn Segmented nuclei Cannot proliferate

Question 32

Monocytes features

Answer 32

Retains potential to divide but it appears usual

Question 33

What regulates erythrocytes

Answer 33

EPO | From kidneys

Question 34

Nutritional factors and co factors required fro erythropoiesis

Answer 34

``` Iron B12 Folate B6 C E Cobalt Manganese Amino acids ```

Question 35

Eosinophils factor

Answer 35

IL5

Question 36

Lymphoid cell line factor

Answer 36

IL7

Question 37

Hb made up of

Answer 37

Porphyrin haem 4poly peptide chains