Module 2: Normal Leukocytes (lymphocytes) Flashcards Preview

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Flashcards in Module 2: Normal Leukocytes (lymphocytes) Deck (33):
1

Leukopoiesis

production of wbc

2

Where are leukocytes produced

bone marrow (neutrophils, eosinophils, basophil, monocyte, few lymphocytes)
lymphatic tissue (lymphocytes, plasma cells)

3

Leukopoietins

specific "poietin" that causes a cell to transform into a mature form

4

cytokines with leukopoietin activity (4)

Interleukins 1-19
GM-CSF (granulocyte/monocyte colony stim factor)
G-CSF (granulocyte)
M-CSF (macrophage)

5

2 major functions of leukocytes

Production of chemical mediators and antibodies result in:
phagocytosis of foreign antigen that is labelled by antibodies
Lysis of foreign and infected body cells by direct killing mechanisms

6

overall functions of leukocytes (6)

Encounters
Recognition
Activation
Deployment
Discrimination
Regulation

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Function: encounters

encounters between foreign antigens and recognition cells (lymphs and macros)
-continuous flow of circulation through lymph nodes
-large # of lymphs and motile macros circulating in blood/lymph/tissue on patrol for foreign antigens

8

Function: Recognition

antigen specific receptor molecules on surface of lymphs and production of specific antibody molecules to bind and identify homologous antigens

9

Function: Activation

lymphs activated when antigen is recognized as foreign
produce antibodies that direct the activities of other cells for immune response

10

Function: Deployment

lymphs unable to destroy antigen by itself
deploys forces and amplify/distribute their own defences and collaborate with non-antigen-specific phagocytes to destroy antigen

11

Function: Discrimination

essential to differentiate between self and foreign antigen (avoid autoimmune tissue damage)

12

Function: Regulation

regulates intensity of immune response so that it has an appropriate antigenic response and shuts off when antigen is eliminated

13

Lymphocyte responsibilities

detection and recognition of foreign antigen/abnormal self-antigen
initiating specific responses against the antigen
direct cytolytic killing
production of antibodies and lymphokines

14

Types of lymphocytes (3)

B Lymphocytes
T Lymphocytes
Null Cells (killer cells, natural killer cells)

15

B lymphocytes

primary source for humeral immune responses (antibody) by transforming into plasma cells

16

T Lymphocytes

cellular immune responses
involved in regulation of antibody reactions by helping or suppressing the activation of B lymphs

17

Null Cells

lack B or T cell surface markers
Killer cells: Antibody dependant cell-mediated lysis
Natural Killer cells: Direct cytotoxic activity

18

How do lymphs differ from other leukocytes (4)

1) resting cells that undergo mitosis into memory/effortor cells when stimulated
2) recirculate back and forth between blood and tissues
3) B and T cell able to rearrange antigen receptor genes to produce different antibodies and surface receptors
4) T and Null cells develop/mature outside of bone marrow

19

Site of lymphocyte maturation

Embryonic: developed from pluripotent cells of yolk sac and liver
Fetal-adult: stem cells in bone marrow

20

What influences stem cells into lymphs

IL1 and IL6 turn stem cell into lymphoid stem cell (CFU-L)
then matures into primary and secondary

21

Primary Lymphoid tissue

do not require antigenic stimulation
Thymus: stem cells multiply under cytokines to become T-lymphs
Bone marrow: stem cells become B-lymphs

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Secondary Lymphoid Tissue

Lymph nodes, spleen, mucosal associated lymphoid tissues
Require antigenic stimulation (an active immune response)
Acts as main storage areas of already differentiated lymphs

23

Lymphoblast characteristics

15-20 um
N:C ratio 4:1
Nucleus: round to oval, 1-2 nucleoli, fine chromatin clumping
Cytoplasm: no granules, medium blue, may have dark blue border

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Prolymphocyte characteristics

15-18um
NC ratio 4:1 to 3:1
Nucleus: oval to slightly indented, 0-1 nucleoli, slightly dense chromatin clumping
Cytoplasm: may have granules, med blue with dark rim

25

Lymphocyte characteristics

6-9um (small)
17-20um (large)
NC ratio 4:1 - 3:1 (small)
2:1 (large)
Nucleus: round to oval, may have indents, no nucleoli, dense clumped chromatin
Cytoplasm: few granules, light blue

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Lymphocyte maturation stages

lymphoblast
prolymphocyte
lymphocyte

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Lymphocyte maturation summary

nucleus gets denser and smaller
loss of nucleoli
granules may form
cytoplasmic color from dark blue to light blue

28

Normal lymphocyte values

birth-4: higher than adults
Adults: 20-40% lymphs
of which 60-80% is T cells, 20-35% B cells
Only mature lymphs are found in peripheral blood
B and T cells cannot be distinguished from each other with routine stain

29

Small Lymph characteristics

Nucleus: round, oval, indented, medium-deep purple, densely clumped, NO NUCLEOLI
Cytoplasm: scant to moderate amount, colourless to royal blue, rarely contains azurophilic granules

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Large lymph characteristics

Nucleus: Round, oval, indented, stretched, light-med purple, slightly less clumped, may contain nucleoli
Cytoplasm: moderate to abundant amount, colourless to blue, may contain azurophilic granules in a localized area

31

Azurophilic granules

non specific granules

32

Variant Lymphocyte

AKA atypical or reactive lymphs
"working" lymphs
normally 5-6% of lymphs seen in peripheral blood
Represent normal immune system
Increased # in viral disorders
Stimulated lymphs with increased DNA/RNA activity

33

Characteristics of variant lymphs

increased size
nucleus folded, indented or lobulated
chromatin clumping varies (fine to dense)
nucleoli may be present (often 1-3)
Cytoplasm foamy, vacuolated, usually abundant
may have azurophilic granules
cytoplasm color from greyish to deep blue