Module 2: Normal Leukocytes (Neutrophils)

Question 1

neutropenia

Answer 1

low neutrophil count

Question 2

neutrophilia

Answer 2

increased neutrophil count
>70%
often seen in acute bacterial infections

Question 3

Normal rel% of neutrophils

Answer 3

50-70%

Question 4

Neutrophil life span

Answer 4

shortest of leukocytes
In bone marrow: 7-10 days
in blood: 10 hours
in tissue: 3-5 days

Question 5

Maturation series of neutrophil (6)

Answer 5

myeloblast
promyelocyte
myelocyte
metamyelocyte
band
segmented neutrophil

Question 6

Myeloblast characteristics

Answer 6

in PBS 0
# in BM 0-2%
15-20um
NC ratio 7:1 - 5:1
Nucleus: round/oval, central, light reddish-blue, fine chromatin, no clumping, 1-3 nucleoli
Cytoplasm: Basophilic blue, scant amount, no granules

Question 7

Promyelocyte characteristics

Answer 7

in PBS 1
# in BM 2-4%
12-24um
NC ratio 5:1 - 3:1
Nucleus: round/oval, central, light reddish-blue, fine chromatin, slight clumping at nuclear membrane, 1-2 nucleoli
Cytoplasm: basophilic (more than blast), azurophilic and nonspecific granules present

Question 8

Myelocyte characteristics

Answer 8

in PBS 0
# in BM 5-20%
10-18um
NC ratio 2:1 - 1:1
Nucleus: oval/round, may have on side indented, usually eccentric, reddish-blue, fine chromatin with slight clumping/granular pattern, 0-2 nucleoli
Cytoplasm: bluish-pink, moderate amount, azurophilic and specific granules present

Question 9

Metamyelocyte characteristics

Answer 9

in PBS 0
# in BM 5-15%
10-18um
NC ratio 1:1
Nucleus: indented, kidney shaped, central, light blue-purple with basophilic blue chromatin (clumped), 0 nucleoli
Cytoplasm: clear pink, moderate amount, specific neutrophilic granules present

Question 10

Band characteristics

Answer 10

in PBS 2-6%
# in BM 10-35%
10-16um
NC ratio 1:1 - 1:2
Nucleus: elongated, horseshoe shaped, central, purplish-red, clumped chromatin, 0 nucleoli
Cytoplasm: pink, abundant, fine violet-pink neutrophilic granules present

Question 11

Segmented neutrophil characteristics

Answer 11

in PBS 50-70%
# in BM 5-15%
10-16um
NC ratio 1:3
Nucleus: 2-5 distinct lobes, central, purplish-red, clumped chromatin, 0 nucleoli
Cytoplasm: Pink, abundant, fine violet-pink neutrophilic granules present

Question 12

at what stage are neutrophils differentiated from other granulocyte cells

Answer 12

myelocyte stage by specific neutrophilic lysosomal granules

Question 13

2 types of granules in neutrophils

Answer 13

primary lysosomes and azurophilic (produced beginning at promyelocyte stage)
Secondary lysosomes or neutrophilic (produced beginning at myelocyte stage)

Question 14

primary (azurophilic/nonspecific) granules (4)

Answer 14

lysozyme
myeloperoxidase
acid phosphatase
elastase

Question 15

Secondary (specific) granules (4)

Answer 15

Lysozyme
NADPH oxidase
Cytochrome b
Lactoferrin

Question 16

Third type of granule (tertiary)

Answer 16

found using electron microscope

Contain plasminogen activator, alkaline phosphatase and gelatinase

Question 17

Neutrophil membrane

Answer 17

receptors: Fc portion of IgG and C3b and C5a
Generous coating of glycoprotein on membrane surface for adherence
High concentrations of cytoskeletal proteins (actin, myosin, tubulin) essential for migration and phagocytosis

Question 18

Neutrophil function

Answer 18

to locate and destroy pathogenic microorganisms by phagocytosis

Question 19

marginating

Answer 19

half of neutrophils are slowly rolling along the endothelium (inside walls of blood vessels)
other half are in circulation

Question 20

Average time in blood before moving to tissue

Answer 20

8-10hrs

**ONE WAY, cannot move back into vessels

Question 21

Migration sequence (3)

Answer 21

1) margination, adherence, anchoring (cell flattens along endothelium)
2) diapedesis (neuts move through junctions in endothelium in response to chemotaxins from site of inflammation)
3) migration (direct or random, other neuts follow)

Question 22

chemical factor signalling neut activation from bacteria

Answer 22

N-formyl oligopeptides

Question 23

chemical factor signalling neut activation from complement

Answer 23

C5a, C3b, C3bi factors

Question 24

chemical factor signalling neut activation from monocytes

Answer 24

IL-8

Question 25

chemical factor signalling neut activation from membrane phospholipid (MOST CHEMOTACTIC)

Answer 25

Leukotriene B

Question 26

chemical factor signalling neut activation from endothelium

Answer 26

platelet activating factor

Question 27

how the neutrophil receives chemotactic substance

Answer 27

surface membrane has receptors
bind to chemotaxin and extend membrane at site of binding
cell extends a pseudopod

Question 28

Killing cascade (5)

Answer 28

1) immune adherence (recognition)
2) endocytosis (englufment)
3) lysosome fusion (granule attaches to wall of phagosome and empty contents into vacuole)
4) Killing and digestion
5) exocytosis

Question 29

Respiratory burst

Answer 29

stimulated from endocytosis
increased glycolysis from pathways produce energy/co-enzymes for oxygen dependent killing reaction
NADPH oxidase from phagosome is activated and causes reduced oxygen to superoxide
Eventually produces HOCl which is highly effective at killing phagosome
AKA peroxide/peroxidase/halide system

Question 30

other killing mechanisms

Answer 30

acid pH kills pneumococcus
microbicidal enzymes (lysozyme-arginase, primary glucoxidase, lactoferrin)
H+ ions in granular proteins kill E. coli
Lysozyme hydrolyzes the mucopolysaccharide walls of some bacteria

Question 31

diapedesis

Answer 31

when neutrophil changes shape to move from blood vessel to tissue

Question 32

maturation series summary

Answer 32

in PBS increases
# in bone marrow increases (until band cell @35%) then decreases
Size: myeloblast to promyelocyte - gets larger
All cells after that get smaller
Overall size from 15-20um to 10-16um
NC ratio Decreases until metamyelocyte (1:1) then increases until seg neutrophil (1:3)
Nucleus: from round, light reddish-blue with fine chromatin and no clumping to lobed, fully clumped, purplish-red
1-3 nucleoli to 0 nucleoli
Cytoplasm basophilic blue with no granules (myeloblast) to azurophilic and specific granules present (myelocyte) to neutrophilic granules only (seg neut)