Leucopoiesis

Question 1

What is the shape of a promyelocyte?

Answer 1

Circular; as matures a band structure forms.

Question 2

What is the differentiating factor between band neutrophils and monocytes?

Answer 2

Band neutrophils are granular.

Monocytes have vacuoles and lack granules.

Question 3

What are the growth factors involved with the development of the promyelocyte?

Answer 3

Stem cell factors
GM - CSF
G - CSF
Interluekin 3

Question 4

What is the point of increased granulocyte activity during gestation?

Answer 4

after 4-5 months

Question 5

Where does the transformation of the myeloblast to the mature granulocyte occur?
How long does it take?

Answer 5

The myeloblast forms in the marrow, then turns into the mature granulocyte in the peripheral blood
6-10 days.

Question 6

Which wbc make up the granulocytes?

Answer 6

Basophils and eosinophils and neutrophils

Question 7

Describe the shape/conformation of the mature neutrophil.

Answer 7

2-3 times the size of healthy red cell
nucleus divided into 2-5 lobes separated by a thin strand or filament of nuclear filament.
Chromatin lumpy
cytoplasm = pale blue/lilac stained granules

Question 8

What is the normal reference range for the absolute no. of neutrophils?

Answer 8

2 - 7 x10^9/L

40-75% of wbc

Question 9

What do female neutrophils have that males do not?

Answer 9

Females - have small lobe called the drumstick - inactive X chromosome.

Question 10

What are the 6 enzymes in the pink/lilac staining granules in neutrophils?

Answer 10

(ALL HAM)
Acid phosphatase
Lactoferrin
Lysozyme
Hydrolases
Alkaline phosphatase
Myeloperoxidase.

Question 11

What are mature neutrophils very dependent on in terms of energy?

Answer 11

On glycolysis and ATP production

Question 12

What is the most common leukocyte and where are they?

Answer 12

Neutrophil;
Half total blood granulocyte are in the CGP (circulating granulocyte pool)
Remainder are in the marginal pool (MGP)

Question 13

What is the MGP associated with?

Answer 13

The loose adherence of leukocytes to the vascular endothelium and tissues.

Question 14

How long do neutrophils spend in the blood ?

Answer 14

Neutrophils spend only on average 10 hours in the blood before passing into the tissues.

Question 15

What accelerated the migration of neutrophils from the blood to the tissues?

Answer 15

Damage or local inflammation.

Question 16

What are the 4 ways in which neutrophils play a role in the killing of bacteria and fungi?

Answer 16

Chemotaxis
Opsonization/adhesion
Ingestion/phagocytosis
Killing phase

Question 17

What is the role of chemotaxis and neutrophils in the killing of bacteria?

Answer 17

N react to specific chemical stimuli called chemotaxins which direct the neutrophils to the site of infection.

Question 18

What are the four chemotaxis activations ?

Answer 18

coagulation (bleeding)
complement (innate immune response)
fibrinolytic (breaks down fibrin)
Kinin (pain)

Question 19

What is the role of neutrophil opsonization in bacteria killing?

Answer 19

This is where the surface of the bacteria is modified to allow neutrophil binding for phagocytosis via specific receptors.

Question 20

What is the role of phagocytosis via neutrophils in bacteria killing?

Answer 20

This is the ingestion of the pathogen through enclosing it in a vacuole and eating via enzymes and proteins in the granules to kill the pathogen.

Question 21

What are the main stages and enzymes involved in the killing phase of bacteria by neutrophils?

Answer 21

Both oxygen dependent and oxygen independent systems involved.
Different proteins and enzymes, both result in killing bacteria.
Myeloid Peroxidase and lysozyme.

Question 22

Which enzyme(s) are involved in the oxygen dependent system of killing bacteria?

Answer 22

Myeloidperoxidase, H2O2 = superoxide and hydroxyl radical formation.

Question 23

Which enzyme(s) are involved in the oxygen independent system of killing bacteria?

Answer 23

Direct action of lysozyme - fall in pH to activate, attacks cell wall of bacteria and bactericidal property of cationic proteins from primary neutrophil granules.

Question 24

What molecules are involved in the process allowing neutrophils to bind to their vascular endotheial cells?

Answer 24

Integrins and selectins - these facilitate N movement through the vascular endothelial cells to the tissue

Question 25

What are stages from stem cell to peripheral blood cell of the neutrophil?

Answer 25

Myeloid Stem Cell, CFU-GEMM, CFU-GM, CFU-G, Myeloblast, Promyelocyte, Myelocyte, Metamyelocyte, Band neutrophil = polynuclear neutrophil.

Question 26

When are primary granules synthesised and what do they compose of?

Answer 26

In the promyelocyte stage - Myeloperoxidase, bacterial permeability inducing factor, lysosome, elastase and acid hydrolases.

Question 27

In acute leukemias where there is mutations in the stem and progenitor cells what is there an increase of?

Answer 27

In blast cells; myeloblastic leukemia - high levels of myeloblasts.

Question 28

What is the colour of the cytoplasm in myeloblasts?

Answer 28

Basophilic - dark purple.

Question 29

What happens to the neutrophil the further it matures?

Answer 29

The nucleus becomes lobed resulting in a segmented neutrophil - held together by strands of chromatin.

Question 30

How is it possible to differentiate between band neutrophils and monocytes?

Answer 30

The band neutrophil is very granular.

Monocyte does not have granules and has many vacuoles.

Question 31

What are CD markers?

Answer 31

These are antigenic markers which are found on all cells in the body but in particular prominent on wbc and wbc precursors.

Question 32

How are CD markers detects?

Answer 32

Via monoclonal antibodies labelled with fluorochromes/fluorescent dyes using flow cytometers.

Question 33

What do CD markers allow us to distinguish?

Answer 33

If an increase in CD markers in the number of blast cells in the marrow - using flow cytometers and fluorescence dye it can be distinguished between myeloblastic leukemia and acute lymphoblastic leukemia.

Question 34

What is the role of the primary granule : myeloperocidase enzyme?

Answer 34

In the non-specific elimination of bacteria, viruses and fungi.
Involved in the conversion of hydrogen peroxide to form hypochlorous acid which has antimicrobial properties.

Question 35

What does the primary granule : bacterial permeability inducing factor bind to?

Answer 35

Binds specifically to lipopolysaccharides and therefore exhibits specificity for GN bacteria increasing bacteria membrane permeability and cell death.

Question 36

What is the role of elastase in the primary granules of neutrophils?

Answer 36

This is effective against GN, fungi and enterotoxins.

Question 37

What is the composition of acid hydrolases in the primary granules of neutrophils?

Answer 37

• acid phosphatase
• B-galactosidase
• B-glucuronidase
• esterases.

Question 38

What ceases prior to the formation of secondary and tertiary granules?

Answer 38

Primary granules

Question 39

what do secondary granules provide?

Answer 39

Distinctive staining patterns used in the identification of granulocytes and their precursors.

Question 40

What do secondary granules contain?

Answer 40

Lactoferrin and lysozyme(found in both primary and secondary).

Question 41

What is the role of lactoferrin in the secondary granules of the neutrophils?

Answer 41

It is bacteriostatic and bactericidal.

Question 42

What are the tertiary granules of the neutrophils composed of?

Answer 42

Gelatinase

Question 43

What is gelatines (in tertiary granules) capable of?

Answer 43

Digesting denatured collagen and intact collagen.

This allows neutrophils to migrate through the blood vessel basement membrane and enter the tissue fluid.