Module 2: Normal Leukocytes (Neutrophils) Flashcards Preview

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Flashcards in Module 2: Normal Leukocytes (Neutrophils) Deck (32):
1

neutropenia

low neutrophil count

2

neutrophilia

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

3

Normal rel% of neutrophils

50-70%

4

Neutrophil life span

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

5

Maturation series of neutrophil (6)

myeloblast
promyelocyte
myelocyte
metamyelocyte
band
segmented neutrophil

6

Myeloblast characteristics

# 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

7

Promyelocyte characteristics

# 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

8

Myelocyte characteristics

# 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

9

Metamyelocyte characteristics

# 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

10

Band characteristics

# 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

11

Segmented neutrophil characteristics

# 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

12

at what stage are neutrophils differentiated from other granulocyte cells

myelocyte stage by specific neutrophilic lysosomal granules

13

2 types of granules in neutrophils

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

14

primary (azurophilic/nonspecific) granules (4)

lysozyme
myeloperoxidase
acid phosphatase
elastase

15

Secondary (specific) granules (4)

Lysozyme
NADPH oxidase
Cytochrome b
Lactoferrin

16

Third type of granule (tertiary)

found using electron microscope
Contain plasminogen activator, alkaline phosphatase and gelatinase

17

Neutrophil membrane

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

18

Neutrophil function

to locate and destroy pathogenic microorganisms by phagocytosis

19

marginating

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

20

Average time in blood before moving to tissue

8-10hrs
**ONE WAY, cannot move back into vessels

21

Migration sequence (3)

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)

22

chemical factor signalling neut activation from bacteria

N-formyl oligopeptides

23

chemical factor signalling neut activation from complement

C5a, C3b, C3bi factors

24

chemical factor signalling neut activation from monocytes

IL-8

25

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

Leukotriene B

26

chemical factor signalling neut activation from endothelium

platelet activating factor

27

how the neutrophil receives chemotactic substance

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

28

Killing cascade (5)

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

29

Respiratory burst

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

30

other killing mechanisms

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

31

diapedesis

when neutrophil changes shape to move from blood vessel to tissue

32

maturation series summary

# 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)