Haemopoiesis

Question 1

What are the four types of haemopoiesis?

Answer 1

• erythropoiesis
• thrombopoiesis
• lymphopoiesis
• myelopoiesis/granulopoiesis

Question 2

How are red cells measured and how long do they last?

Answer 2

x10^12/l

120 days

Question 3

How are neutrophils measured and how long do they last?

Answer 3

x10^9/l

7-8 hours

Question 4

How are platelets measured and how long do they last?

Answer 4

x10^9/l

7-10 days

Question 5

What does ‘blast’ mean?

Answer 5

Nucleated precursor cell

Question 6

What is a megakaryocyte?

Answer 6

Platelet precursor

Question 7

What is a myelocyte?

Answer 7

Nucleated precursor between neutrophils and blasts

Question 8

Describe haemopoietic stem cells

Answer 8

Progenitor with the ability to self-renew

Asymmetrical division allows stem cell preservation and differentiation

Question 9

Define maturation

Answer 9

Acquisition of functional properties

Question 10

What can myeloid mean?

Answer 10

Marrow
Non-lymphoid lineage
Granulocytic portion of the marrow

Question 11

Where does marrow originate embryonically?

Answer 11

Mesoderm

Question 12

When can progenitors be detected?

Answer 12

As early as week 5

Question 13

Where is the first place to produce stem cells?

Answer 13

Yolk sac

Question 14

When does yolk sac activity stop?

Answer 14

Week 10

Question 15

When do the marrow and liver start to produce stem cells?

Answer 15

Liver - week 6

Bone marrow - week 16

Question 16

What is meant by cellularity?

Answer 16

Percentage of active cells in marrow
Red marrow
Yellow marrow - fatty and inactive increases with age

Question 17

Where are bone marrow biopsies taken?

Answer 17

Adult - posterior iliac crest

Children - tibial marrow cavity

Question 18

Name the three compartments of the bone marrow

Answer 18

Cellular
Connective tissue matrix
Vascular elements

Question 19

What non-haemopoieotic cells are found in the marrow?

Answer 19

Adipocytes, fibroblasts, osteoclasts, osteoblasts

Question 20

Describe the vasculature of the marrow

Answer 20

Nutrient artery and periosteal network

Sinuses and sinusoids

Question 21

How are sinusoids different to capillaries?

Answer 21

Larger and have a discontinuous basement membrane

Question 22

Describe the structure of sinusoids

Answer 22

Endothelial cells with a discontinuous BM, gaps in between cells and adventitial cells which can alter the space

Question 23

What do the sinusoids create?

Answer 23

Pores/fentrations that allow mature cells to migrate through and enter the circulation

Question 24

Describe sinusoid response to blood loss

Answer 24

Dilatation to increase blood flow

Question 25

Which direction do neutrophils travel?

Answer 25

Down the chemokine gradient - towards the sinusoid

Question 26

Describe the relationship between megakaryocyte and sinusoidal blood vessels

Answer 26

Megakaryocytes extend long branching processes - pro platelets into the sinusoidal blood vessels

Question 27

State the three components of regulation of erythropoiesis

Answer 27

Intrinsic properties of cells
Signals from immediate surroundings of periphery
Specific anatomical area ‘niche’ for optimal developmental signals

Question 28

Give examples of marrow regulation

Answer 28

Renal erythropoietin
Erythroid islands ‘nurse’ macrophages, growth factors provided
Neutrophil precursor maturation regulated by GCSF
Thrombopoietin from the liver regulates growth and development of megakaryocytic

Question 29

What is GCSF?

Answer 29

Granulocyte colony stimulating factor

Question 30

How can marrow be investigated?

Answer 30

Blood count 
Cell inidices 
Morphology 
Bone marrow examination 
Immunophenotyping 
Cytochemistry

Question 31

Describe immunophenotyping

Answer 31

Study of antigen expression using specific antibodies indicating lineage/stage of development