Haemopoiesis

Question 1

What is the normal range of RBCs?

Answer 1

3-5 x 10^12/L

Question 2

What is the normal range of WBCs?

Answer 2

2-6 x 10^9/L

Question 3

What is the normal range of platelets?

Answer 3

150-400 x 10^9/L

Question 4

What is the normal lifespan of RBCs?

Answer 4

120 days

Question 5

What is the normal lifespan of WBCs?

Answer 5

3-5 days

Question 6

What is the normal lifespan of platelets?

Answer 6

10 days

Question 7

How does the site of haemopoiesis change over the lifespan?

Answer 7

1st few weeks: yolk sac
6 weeks - 7 months: liver and spleen
7 months - throughout life: bone marrow (axial skeleton and long bones initially, then just axial)

Question 8

When are the liver and spleen used for haemopoiesis besides in the 6 week - 7 month period?

Answer 8

In childhood or adult pathology of the bone marrow

Question 9

What % of bone marrow consists of fat spaces? In what areas?

Answer 9

50%

In all marrow, even in active haemopoietic areas

Question 10

What are the main sites of haemopoiesis in an adult (aged >40-50)?

Answer 10

Pelvis
Sternum
Spine
Maybe some ribs

Question 11

What is the pluripotent stem cell and what is its role in haemopoiesis?

Answer 11

A cell capable of self renewal that differentiates into all haemopoietic cell lines (as well as osteoclasts)

Question 12

In what kind of numbers do pluripotent stem cells exist in the marrow?

Answer 12

Small numbers (1 in 100,000 in mice studies)

Question 13

What is a CFU? Can this be distinguished using microscopy?

Answer 13

Colony-forming unit

No - appear no different histologically but behave in a characteristic way

Question 14

What is the role of the bone marrow stroma?

Answer 14

Provides a specific supportive microenvironment for bone marrow to grow
Ensures immature cells are not released into the peripheral blood

Question 15

How are immature cells kept in the bone marrow?

Answer 15

Attached via various adhesion molecules to the bone marrow stroma (ECM and cells)
Changes in adhesion molecules mark the progression of cells through the stroma

Question 16

Is the bone marrow separate from or in continuity with the systemic circulation?

Answer 16

In continuity with

Question 17

How is a bone marrow transplant administered?

Answer 17

Via a central line (finds the microenvironment of the stroma and settles in, anchoring to adhesion molecules)

Question 18

List 5 elements of the bone marrow ECM

Answer 18

Fibronectin
Haemonectin
Laminin
Collagen
Proteoglycans

Question 19

List 5 cells of the bone marrow stroma

Answer 19

Macrophages
Fibroblasts
Endothelial cells
Fat cells
Reticulum cells

Question 20

When can individual cell types and stages of maturation be accurately determined under the microscope?

Answer 20

Beyond the CFU stage

Question 21

What are haemopoietic growth factors? Are they specific to single lineages or can they work across several?

Answer 21

Glycoprotein hormones which act locally and via the circulation to direct haemopoiesis; effects are mediated through specific receptors
May act specifically on 1 lineage or work across lineages (may also stimulate self renewal, e.g. SC factor for the HSC)

Question 22

What is the effect of GM-CSF on an early cell vs. a late cell?

Answer 22

Early cell: promotes proliferation/maturation

Late cell: promotes activation to enhance phagocytosis, killing and secretion

Question 23

Give 3 examples of haematinics

Answer 23

Iron
Vitamin B12
Folate

Question 24

What is required for functional Hb?

Answer 24

Functional a chain
Functional B chain
Iron

Question 25

What is the role of iron in RBC function?

Answer 25

Critical to maintain production

Question 26

What are 2 possible causes of iron deficiency?

Answer 26

Inadequate diet

Blood loss

Question 27

In what foods is vitamin B12 found? Where is it not found?

Answer 27

Animal products (meat, fish, dairy)
Not in fruits, cereals or vegetables

Question 28

What is the role of vitamin B12 in RBC function?

Answer 28

Important for all rapidly produced cells

Question 29

In what foods is folate found?

Answer 29

Green leafy vegetables

Question 30

Give an example of a drug which can cause folate deficiency

Answer 30

Methotrexate