Haemopoiesis

Question 1

What is haemopoiesis?

Answer 1

The formation of blood cells

Question 2

What is the process through which platelets are made?

Answer 2

Thrombopoiesis

Question 3

What is the process through which granulocytes and monocytes are made?

Answer 3

Granulopoiesis or myelopoiesis

Question 4

What is the process through which lymphocytes are made?

Answer 4

Lymphopoiesis

Question 5

What is the red cell lifespan?

Answer 5

120 days

Question 6

What is the neutrophil lifespan?

Answer 6

7-8hrs

Question 7

What is the platelet lifespan?

Answer 7

7-10 days

Question 8

What does ‘blast’ mean?

Answer 8

Primitive nucleated precursor

Question 9

What is a megakaryocyte?

Answer 9

Platelet precursor, polypoid

Question 10

What is a myelocyte?

Answer 10

Nucleated precursor between neutrophils and blasts

Question 11

What are all haemopoietic cells derived from?

Answer 11

Haemopoietic stem cells

Question 12

What are haemopoietic stem cells derived from?

Answer 12

Mesoderm

Question 13

When are circulating committed progenitors detectable from?

Answer 13

Early as week 5

Question 14

When does the yolk sac, the first site of erythroid activity, stop producing cells by?

Answer 14

Week 10

Question 15

When does the liver, spleen and bone marrow begin haemopoiesis?

Answer 15

Week 6,12 (spleen has small contribution in humans) and 16 respectively

Question 16

What are the compartments of bone marrow?

Answer 16

Cellular- haemopoietic/non-haemopoietic cells
Vascular elements
Connective tissue matrix

Question 17

What minute projections of bone are found throughout the metaphysis such that many cells in this region are close to the bone surface?

Answer 17

Trabeculae

Question 18

What is the interface of bone and bone marrow known as?

Answer 18

Endosteum

Question 19

What are sinusoids?

Answer 19

Specialised venules that form a reticular network of fenestrated (with apertures) vessels

Question 20

What do arteries feed into bone?

Answer 20

Sinusoids

Question 21

What can formed blood cells pass through in endothelial cells to enter circulation?

Answer 21

Fenestrations

Question 22

Where do neutrophils actively migrate towards?

Answer 22

Sinusoid

Question 23

What long branching processes do megakaryocytes extend into the sinusoidal blood vessels?

Answer 23

Proplatelets

Question 24

What marrow is haemopoietically active and fatty inactive?

Answer 24

Red and yellow respectively (increased yellow with age)

Question 25

How is marrow cellularity calculated?

Answer 25

100-age=cellularity (%)

Question 26

What is the myeloid:erythroid ratio?

Answer 26

Relationship of neutrophils and precursors to proportion of nucleated red cell precursors (ranges from 1.5:1 to 3.3:1)– can change (eg reversal in haemolysis as a compensatory response)

Question 27

What regulates haemopoiesis?

Answer 27

Complex interplay of ‘random’ intrinsic properties of cells (particularly stem cells) and signals from immediate surroundings and the periphery (microenvironmental factors) Activation of lineage-specific transcription factors

Question 28

What is neutrophil maturation regulated by?

Answer 28

Granulocyte colony stimulating factor (G-CSF)

Question 29

What does thrombopoietin regulate growth and development of?

Answer 29

Megakaryocytes from their precursors

Question 30

What does erythroid maturation occur around in the form of islands?

Answer 30

Nurse macrophages

Question 31

What are the clinical implications of the haemopoietic niche for the haemopoietic stem cell (HSC)?

Answer 31

Niche can shift in states of marrow stress | Drug therapy can be used to mobilise HSC from niche for collection and transportation

Question 32

How do we assess haemopoiesis?

Answer 32

Routine- blood count, cell indices, morphology | Less common- bone marrow examination

Question 33

What is the study of antigen expression using specific antibodies?

Answer 33

Immunophenotyping

Question 34

What are specialist tests for haemopoiesis on rare populations of cells/morphologically indistinguishable cells?

Answer 34

Immunophenotyping Cytochemistry Clonogenic assays Animal models

Question 35

What does immunophenotyping sense on the antibody-antigen complex?

Answer 35

Fluorochrome