Physiology - Haematopoiesis

Question 1

What are the three main types of blood cells?

Answer 1

Red blood cells
White blood cells
Platelets

Question 2

What is the term for the production of blood cells?

Answer 2

Haematopoiesis

Question 3

Where does haematopoiesis occur in the embryo?

Answer 3

Yolk sac, then liver, then marrow

3rd to 7th month –> spleen

Question 4

Where does haematopoiesis occur at birth?

Answer 4

Mostly bone marrow

Liver + spleen when needed

Question 5

Where does haematopoiesis occur in adults?

Answer 5

Bone marrow only:

• skull, ribs, sternum, pelvis + proximal femur (axial skeleton)
• not all bones contain bone marrow

Question 6

From which type of cell are all blood cells derived?

Answer 6

Haematopoietic stem cells

Question 7

What are the different types of white blood cells?

Answer 7

Granulocytes:
- neutrophils
- eosinophils
- basophils
Monocytes:
- macrophages
Lymphocytes:
- B cells
- T cells
- NK cells

Question 8

What are neutrophils responsible for?

Answer 8

Phagocytosis/acute inflammation

Question 9

What are eosinophils responsible for?

Answer 9

Destroy parasites

Modulate hypersensitivity reactions

Question 10

What are basophils for?

Answer 10

Modulate hypersensitivity reactions

Circulating version of tissue mast cell

Question 11

What are macrophages responsible for?

Answer 11

Modulate immune reactions
Phagocytic clearance
Regulatory functions

Question 12

What are B cells responsible for?

Answer 12

Humoral immunity (antibodies)

Question 13

What are T cells responsible for?

Answer 13

Cell-mediated immunity

Regulatory functions

Question 14

What are NK cells responsible for?

Answer 14

Anti-viral/tumour

Question 15

What is the lifespan of a red blood cell?

Answer 15

about 120 days

Question 16

What is the lifespan of a neutrophil?

Answer 16

7-8 hours

Question 17

What is the lifespan of a platelet?

Answer 17

7-10 days

Question 18

What do ‘blasts’ refer to in haematopoiesis?

Answer 18

Nucleated precursor cells e.g. erythroblast, myeloblast

Question 19

What is the platelet precursor cell called?

Answer 19

Megakaryocyte

Question 20

What is the immediate red cell precursor called?

Answer 20

Reticulocyte (immature RBC)

Question 21

What does a neutrophil look like under a microscope?

Answer 21

Segmented nucleus (polymorph)
Neutral staining granules

Question 22

What do eosinophils look like under a microscope?

Answer 22

Usually bi-lobed

Bright orange/red granules

Question 23

What do basophils look like under a miscroscope?

Answer 23

Infrequent in circulation

Large deep purple granules obscuring nucleus

Question 24

What do monocytes look like under a microscope?

Answer 24

Large single nucleus

Faintly staining granules, often vacuolated

Question 25

What do lymphocytes look like under a microscope?

Answer 25

Mature: small with condensed nucleus + rim of cytoplasm
Activated (often called atypical): large with plentiful blue cytoplasm extending around neighbouring red cells on the film, nucleus more ‘open’ structure

Question 26

Which investigations can be done to identify the more primitive precursor cells?

Answer 26

Immunophenotyping
- expression profile of proteins (antigens) on surface of cells

Bio-assays
- culture in vitro and show lineage of progeny in different growth conditions

(cant be identified on blood films)

Question 27

How do you examine the haematopoietic system?

Answer 27

Peripheral blood: blood count, cell indices, morphology
Look at bone marrow
Specialised tests of bone marrow
Other sights relevant to blood production e.g. splenomegaly, hepatomegaly, lymphadenopathy

Question 28

What is the most common site for bone marrow aspiration/biopsy?

Answer 28

Posterior iliac crests

Question 29

What is the difference betweek red and yellow marrow?

Answer 29

Red = haemopoietically active
Yellow = fatty, inactive

Question 30

What is the myeloid:erythroid ratio?

Answer 30

Ratio of neutrophil + precursors to nucleated red cell precursors

Question 31

What is the most appropriate technique to assign cell lineage?

Answer 31

Immunophenotyping