Haemopoiesis

Question 1

What is haemopoiesis?

Answer 1

Formation of blood cells

Question 2

What are the different mature blood cells?

Answer 2

Red cells
Platelets
Neutrophils
Eosinophils
Basophils
Monocytes / macrophages 
Lymphocytes - B cells / T cells / NK cells

Question 3

What cells are involved in modulating hypersensitivity reactions ?

Answer 3

Basophils

Question 4

What cells are involved in destroying parasites and modulating hypersensitivity reactions?

Answer 4

Eosinophils

Question 5

What cells are involved in phagocytosis and acute inflammation?

Answer 5

Neutrophils

Question 6

What is the lifespan of red cells?

Answer 6

120 days

Question 7

What is the life span of neutrophils?

Answer 7

7-8 hours

Question 8

What is the lifespan of platelets?

Answer 8

7-10 days

Question 9

Platelet precursor?

Answer 9

Megakaryocyte

Question 10

Red cell precursor?

Answer 10

reticulocytes

Question 11

Neutrophils and blast precursor?

Answer 11

Myelocytes

Question 12

Where do precursor cells come from?

Answer 12

Haemopoietic progenitor cells

Question 13

Where do progenitor and haemopoietic cells come from?

Answer 13

Haemopoietic stem cells

Question 14

Where are haemopoietic stem cells derived from?

Answer 14

Mesoderm

Question 15

Prenatally, when are circulating progenitors detectable from?

Answer 15

Week 5

Question 16

Prenatal sites of haemopoiesis?

Answer 16

Yolk sack - stops by week 10
Liver - starts at week 6
Spleen - starts at week 12
Bone marrow - starts at week 16

Question 17

Postnatally, where does haemopoiesis occur?

Answer 17

Bone marrow of :

• tibia ( stops about age 20)
• femur ( strops about age 25)
• vertebra
• sternum
• rib

Question 18

What compartments make up the bone marrow??

Answer 18

Haemopoietic cells
Non haemopoietic cells
Connective tissue matrix
Vascular elements

Question 19

What are the non haemopoietic cells in the bone marrow?

Answer 19

Adipocytes
Fibroblast
Osteoclasts
Osteoblasts

Question 20

What about the sinus basement membrane ?

Answer 20

It is discontinuous

Question 21

What is the process of mature cells being released from the bone marrow?

Answer 21

Blood cells pass through fenestrations in the endothelial cells and enter circulation
Release is associated with sinusoid all dilatation and increased blood flow
Neutrophils migrate towards sinusoid
Megakaryocytes extend proplatelets into sinusoid all blood vessels

Question 22

What marrow is haemopoietically active?

Answer 22

Red marrow

Question 23

What marrow is fatty and inactive?

Answer 23

Yellow marrow

Question 24

What marrow increases with age?

Answer 24

Yellow marrow

Question 25

An increase in yellow marrow has what result?

Answer 25

Reduction in marrow cellularity in older individuals

Question 26

How do you assess haemopoiesis?

Answer 26

Blood count , Cell indices , Morphology ( blood film)
Bone marrow examination
Immunophenotyping

Question 27

What factors regulate haemopoiesis?

Answer 27

Intrinsic factors of the cells
Microenvironmental factors 
Erythroid maturation occurring with macrophages 
G-CSF - regulates neutrophil maturation 
Thrombopoietin regulating megakaryocytes

Question 28

What are the micro environmental factors regulating haemopoiesis?

Answer 28

Haemopoietic stem cells occupy a niche
Niche is around vasculature which provides access to different signals
Niche can be altered in diseased star or with therapy