Haematopoiesis

Question 1

What 4 things should you do when interpreting results?

Answer 1

Know what normal is for each species
Look for patterns
Link things together and try to provide an explanation
Classify degree of change

Question 2

Where are blood cells produced in mammals?

Answer 2

Bone marrow and lymphoid organs

Question 3

Where are blood cells produced in adult birds?

Answer 3

Bone marrow

Question 4

Where are blood cells produced in adult reptiles?

Answer 4

Bone marrow and spleen

Question 5

Where are blood cells produced in amphibians?

Answer 5

Kidney
Liver
Spleen
and/or bone marrow

Question 6

Where are blood cells produced in fish?

Answer 6

Kidney

and/or spleen

Question 7

What does the prefix ‘myelo’ generally refer to?

Answer 7

All aspects of bone marrow activity, not just granulocytic elements alone

Question 8

What does myelopoiesis chiefly consist of?

Answer 8

Erythropoiesis
Granulopoiesis
Thrombopoiesis

Question 9

Where are monocytes formed?

Answer 9

In the marrow and elsewhere

Question 10

Where does lymphopoiesis occur mostly?

Answer 10

Extramedullary sites -
Spleen
Thymus
Lymph nodes

Question 11

What are haematopoietic cells and where are they found?

Answer 11

They are precursors to haemic cells found in blood or tissue

Question 12

Do haematopoietic stem cells develop diffusely in the bone marrow or in specific niches?

Answer 12

Specific niches

Question 13

In the bone marrow where do megakaryocytes form?

Answer 13

Adjacent to sinusoidal endothelial cells

Question 14

In the bone marrow where to erythroid cells develop?

Answer 14

Around macrophages

Question 15

In the bone marrow where do granulocytes develop?

Answer 15

Associated with stromal cells away from vascular sinuses

Question 16

Where are haematopoietic growth factors produced?

Answer 16

Locally by paracrine or autocrine

Or by peripheral endocrine tissues and transported by blood to the bone marrow

Question 17

What cells produce HGF and/or inhibitors?

Answer 17

All cells in the haematopoietic microenvironment

-including the haematopoietic cells

Question 18

What are 4 haematopoietic growth factors?

Answer 18

Erythropoietin - EPO
Thrombopoietin - TPO
Colony stimulating factors - CSF
Interleukins - IL

Question 19

What 3 processes make up haematopoiesis? (not steps)

Answer 19

Erythropoiesis
Leukopoiesis
Thrombopoiesis

Question 20

Where is erythropoietin produced?

Answer 20

Predominantly by peritublar interstitial cells of the kidney

Also in bone marrow and sometimes liver

Question 21

What causes release of erythropoietin?

Answer 21

Low tissue oxygen levels

Question 22

What is the time frame from going from rubriblast to metarubricyte production?

Answer 22

3-4 days

Question 23

Where are inhibitory cytokines produced?

Answer 23

Sites of inflammation in the body

Question 24

What 3 nutrients are needed for erythropoiesis?

Answer 24

Iron - heme synthesis
Vitamin B6 - cofactor in heme synthesis
Copper - release of iron from tissue, into plasma, to transport developing erythroid cells

Question 25

What are the 6 cells of erythropoiesis?

Answer 25

``` Rubriblast Prorubricyte Rubricyte Metarubricyte Reticulocyte/polychromatophil Erytrhocyte ```

Question 26

What percentage of blood can be made of reticulocytes in dogs and cats?

Answer 26

1 - 1.5%

Question 27

What stage of erythropoiesis stops when critical haemoglobin concentration is reached?

Answer 27

Cell division of rubricytes

Question 28

What can happen during erythropoiesis if there is haemoglobin deficiency (iron deficiency)

Answer 28

Get microcytes

Question 29

What species will you not normally find healthy retics in the peripheral blood?

Answer 29

Horse Cow Sheep Goat

Question 30

On a Romanowsky type blood stain, what is the colour difference between early precursors and mature cells?

Answer 30

Early - blue cytoplasm | Late - red cytoplasm

Question 31

Why do romanowsky blood stain make early erythroid precursors blue?

Answer 31

The cytoplasm is blue due to many basophilic ribosomes and polyribosomes synthesising globin chains

Question 32

As erythroid cells mature what changes occur?

Answer 32

Size decreases Nuclear chromatin condenses Cytoplasmic basophilia decreases Hb progressively accumulates which makes them appear red on a Romanowsky blood stain

Question 33

Where does reticulocyte maturation begin and finish?

Answer 33

Begins in bone marrow | Finishes in peripheral blood and spleen

Question 34

What is the basic dye you use for reticulocytes?

Answer 34

New methylene blue

Question 35

What is the significance of seeing a network of reticulum in a reticulocyte under microscope?

Answer 35

It is an artifact | -From precipitation of ribosomal ribonucleic acids and proteins secondary to staining

Question 36

What are the 3 types of myelocytes?

Answer 36

Neutrophils Eosinophils Basophils

Question 37

Are the granules in myelocytes peroxidase negative or positive?

Answer 37

Peroxidase negative

Question 38

How do you differentiate myelocytes?

Answer 38

By their granule staining properties Basophils - granules with affinity for blue dye Eosinophils - stain reddish-orange with eosin Neutrophils - Granules don't stain with either dye

Question 39

In dogs how many more mature neutrophils are stored in the bone marrow compared to the blood stream?

Answer 39

x 7 more in bone marrow

Question 40

How long is marrow transit time of neutrophils from myeloblast to release of mature neutrophil?

Answer 40

6-9 days

Question 41

What happens to the transit time of neutrophils in the presence of inflammation?

Answer 41

It is shortened

Question 42

What is the marrow transit time of an eosinophil?

Answer 42

1 week

Question 43

What is the connection between basophils and mast cell?

Answer 43

They have the same progenitor cell | However basophils mature in the bone marrow whilst mast cells mature in tissues

Question 44

What is the chief stimulator of thrombopoiesis? And where is it produced?

Answer 44

Thrombopoietin | Produced in the liver mainly, somewhat in the kidney and bone marrow

Question 45

What are the 4 cells of thrombopoiesis?

Answer 45

Megakaryblast Promegakaryocyte Megakaryocyte Thrombocyte (platelet)

Question 46

What change occurs to the cytoplasm during thrombopoiesis?

Answer 46

Early stages is deeply basophilic | Later the cytoplasm gets a pink hue

Question 47

What are the 5 general disorders of the bone marrow?

Answer 47

``` Aplasia/hypoplasia Hyperplasia Dysplasia Myelopthisis Neoplasia ```

Question 48

What are some mechanisms of disease for aplasia/hypoplasia of bone marrow?

Answer 48

Oestrogen toxicity Drugs - Griseofulvin toxicity in cats Poisoning - brackern fern in cattle and sheep Infection - Parvo Systemic disease - chronic renal failure, endocrine deficencies

Question 49

What are the 2 types of erythroid hyperplasia?

Answer 49

Effective - increased reticulocytosis in response to anaemia | Ineffective - severe iron deficiency, some myeloproliferative or myelodysplastic disorders

Question 50

What are the 2 types of granulocytic hyperplasia?

Answer 50

Effective - Neutrophilia in response to bacterial infection, immune mediated inflammatory disorder, necrosis, chemical or drug toxicities, malignances Ineffective - persistent neutropaenia with bone marrow neutrophil hyperplasia in myelodysplastic disorders or acute myelocytic leukaemia

Question 51

What are the 2 types of dysplasia of bone marrow?

Answer 51

Dyserythropoiesis - abnormal maturation and/or morphology associated with ineffective erythropoiesis Dysgranulopoiesis - abnormal granulocyte and/or morphology associated with ineffective granulopoiesis

Question 52

What is myelopthisis?

Answer 52

Replacement of normal haematopoietic cells with abnormal cells Alteration of marrow microenvironment which results in normal haemopoiesis being compromised

Question 53

What is myelofibrosis and what does it result in?

Answer 53

Bone marrow injury due to necrosis, vascular damage, inflammation or neoplasia Resulting in excess collagen or reticulum

Question 54

What are the 5 kinds of haematopoietic origin neoplasia?

Answer 54

Lymphoid leukaemia Myelomonocytic Erytrholeukaemia Megakaryblastic

Question 55

What are the 3 kinds of non-haematopoietic origin neoplasia?

Answer 55

Mast cell tumour Metastatic carcinoma Sarcoma of bone