Week 2- haemopoeisis

Question 1

What is haemopoeisis?

Answer 1

The production of blood cells.

Question 2

What are all the mature blood cells called?

Answer 2

Erythrocytes

Platelets

White blood cells-
Neutrophils
Eosinophils
Basophils
Granulocytes
Monocytes- macrophages
Lymphocytes- B cells, T cell and NK cells.

Question 3

What is myelopoeisis?

Answer 3

Production of granulocytes and monocytes within the bone marrow (also known as granulopoeisis).

Question 4

What is thrombopoeisis?

Answer 4

Production of platelets (also known as thrombocytes)

Question 5

Life span of a RBC?

Answer 5

120 days

Question 6

Life span of neutrophils

Answer 6

6-8 hours

Question 7

Life span of platelets

Answer 7

7-10 days

Question 8

What does the suffix ‘blast’ mean?

Answer 8

Precursor cell
Erythroblast- red precursor cell
Myeloblast-precursor granulocyte.

Question 9

What is a megakaryocyte?

Answer 9

Platelet precursor.

Question 10

What are reticulocytes?

Answer 10

Polychromatic immediate red cell precursors (as red cells are released from the marrow- this is what they are).

Question 11

What are myelocytes?

Answer 11

Nucleated precursors between neutrophils and neutroblasts.

Question 12

Where do all these precursor cells come from?

Answer 12

Haemopoetic progenitor cells.

Question 13

Describe the developmental events in haemopoeisis?

Answer 13

Self renewal- a property of stem cells lost in descendants
Proliferation- increase in numbers
Differentiation- descendants commit to one or more lineage
Maturation- descendents acquire functional properties and may stop proliferating
Apoptosis- descendants undergo cell death.

Question 14

Describe how the location of haemopoeisis changes during development?

Answer 14

Yolk sac- first sight of erythroid activity stops by week 10
Liver- starts by week 6
Spleen- starts by week 12
Bone marrow- starts by week 16. 
In adults- moves to axial skeleton.

Question 15

How does the location of haemopoeisis affect how you would withdraw bone marrow biopsies?

Answer 15

In children- use the anterior tibia

In adults- use PSIS.

Question 16

What non-haemopoetic cells also occupy the bone marrow?

Answer 16

Osteoclasts and osteoblasts

Adipocytes (fat tissue)

Question 17

Describe the vasculature of the bone marrow?

Answer 17

The nutrient artery supplies it. Arterioles branch into the bone to supply it. The arteries drain into sinus’s which have large pools of blood.

Question 18

How can mature cells exit the marrow?

Answer 18

Formed blood cells can pass through fenestrations in endothelial cells to enter the circulation.

Question 19

What is release of red cells associated with (in terms of the sinus’s)?
What do neutrophils do?
What do megakaryocytes do?

Answer 19

Associated with sinusoidal dilatation and increased blood flow.
Neutrophils actively migrate towards the sinusoid.
Megakaryocytes extend long branching processes into the sinusoid blood vessels.

Question 20

What does having red marrow mean?

Answer 20

Its haemopoetically active

Question 21

What does having yellow marrow mean?

Answer 21

Its fatty and inactive.

Question 22

How does the marrow change as we get older? (in terms of yellow and red)

Answer 22

You get an increase in yellow marrow with age meaning you get a reduction in marrow cellularity.

Question 23

What is the myeloid: erythroid relationship?

Answer 23

Relationship of neutrophils and its precursors to the number of red cell precursors.

Question 24

What two things can regulate haemopoeisis?

Answer 24

Intrinsic properties of cells (stem cells vs progenitor cells vs mature cells)
Signals from immediate surroundings and the peripheries.

Question 25

What regulates growth and development of megakaryocytes?

Answer 25

Thrombopeotin.

Question 26

Where does erythroid maturation occur? (in terms of cells)

Answer 26

Around nurse macrophages in the forms of islands.

Question 27

What regulates neutrophils and its precursors?

Answer 27

G-CSF

Granulocyte colony stimulating factor

Question 28

What is the study of antigen expression using specific antibodies called?

Answer 28

Immunophenotyping

Question 29

How does immunophenotyping work?

Answer 29

Identifies patterns of proteins unique to cell lineage. Uses antibodies that are specific to different antigens.