Physiology of normal white blood cells Flashcards

1
Q

what cells are from myeloid progeny

A

erythrocytes, platelets, basophils, eosinophils, neutrophils and monocytes

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2
Q

what cells are from lymphoid progeny

A

B and T lymphocytes and NK cells

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3
Q

what cells are leucocytes

A

B cell, T cell, large granular lymphocyte, mononuclear phagocyte, neutrophil, eosinophil and basophil

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4
Q

what cells are phagocytes

A

mononuclear phagocyte, neutrophil and eosinophil

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5
Q

what cells are auxiliary cells

A

basophil, mast cell and platelets

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6
Q

what cells are granulocytes

A

neutrophil, basophil and eosinophil

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7
Q

how many lymphocytes are NK cells

A

Approximately 5% of lymphocytes are NK cells – do not have antigen specific receptors

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8
Q

what are basophils

A

Lobed nuclei, heavily granulated cytoplasm

Non phagocytic cells

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9
Q

what do basophils do

A

Function by releasing pharmacologically active substances from their cytoplasmic granules
Circulate in blood
Recruited to sites of allergic reaction or parasitic infection
Express F epsilon R1 - can bind to allergen specific IgE so allergen can bind to basophils causing degranulation of effector mediators

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10
Q

what are eosinophils

A

Have bilobed nuclei and granulated cytoplasm
Motile phagocytic cells that migrate from blood into tissues
Majority are located in tissues

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11
Q

what do eosinophils do

A

Recruited to sites of allergic reaction
Express FC epsilom R1 upon activation (bind to IgE)
Granules containing toxins eg peroxidases
Attach parasites in GI, respiratory and genito-urinary tracts

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12
Q

what are neutrophils

A

(polymorphonuclear cells)
Multilobed nucleus
Found in blood (60% of circulating leucocytes)

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13
Q

what do neutrophils do

A

Rapidly recruited to sites of infection/injury (short lifespan (8hr-4days)
Phagocytic, myeloperoxidase and ROS
First responders, numbers increased in blood during bacterial infection

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14
Q

what are monocytes

A

Kidney shaped nucleus Blood born phagocytes

Precursors to macrophages

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15
Q

what do monocytes do

A

Reservoir of monocytes in the spleen
Circulate in bloodstream where they enlarge
Migrate into tissues approx. 1 day after release from bone marrow

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16
Q

what are macrophages

A

Found in tissues (tissue specific)
5-10 fold larger than monocytes and Contain many more organelles
Lifespan months to years

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17
Q

what do macrophages do

A

Tissue born phagocytes

18
Q

what cells increase in bacterial infection

A

neutrophils (monocytes in chronic infection)

19
Q

what cells increase in viral infection

A

lymphocytes, sometimes monocytes)

20
Q

what cells increase in parasitic infection

A

eosinophils + activation of mast cells

21
Q

what cells increase in fungal infection

A

monocytes

22
Q

what cells increase in allergy

A

basophils (eosinophils in chronic phase), activation of mast cells

23
Q

how is leucocyte function regulated

A

Recruitment of leucocytes from blood to tissues is key to their immune functions
(interactions with blood vessels is key to recruitment)

24
Q

what are cytokines

A

Act as messenger molecules of immune system
Assist in regulating the development of immune effector cells
Generally act locally (paracrine signalling)

25
Q

what do cytokines do

A

Low molecular weight (>30kDa) regulatory proteins or glycoproteins
Secreted primarily by WBCs

26
Q

what are chemokine

A

Type of cytokine that induce directed chemotaxis in local responsive cells

27
Q

what do chemokine do

A

Chemokines function mainly as attractant for leucocytes, recruit monocytes and neutrophils to site of infections
Important monocyte chemokines MCP-1 (monocyte chemotactic protein-1)
AKA CCL-2

28
Q

what is inflammation

A

A response of vascularised tissue to infections and damaged tissues (heat redness pain and swelling)
`Aim is to bring cells and molecules involved in host defence and repair to site of infection/injury

29
Q

what are the mechanisms of inflammation

A

Components: blood vessels, phagocytic leucocytes, plasma proteins (eg complement, antibodies)
Overview:
Blood vessels dilate
“ more permeable
Circulating leucocytes to migrate blood to tissue
Activated
destroy microbes and any unwanted material

30
Q

what is the difference between acute and chronic infection

A

Time it lasts
Speed of development
Healing (resolved when stimulus removed in acute, attempts and tissue destruction in chronic)
acute- neutrophils
chronic- mononuclear cells (eg macrophages and lymphocytes)

31
Q

what are the types of cell adhesion to the endothelium

A

Initial contact – P and E-selectin on endothelium recognised by oligosaccharides on leucocytes
Tighter adhesion – intercellular adhesion molecules (ICAMS) on the endothelium recognise integrins on leucocytes

32
Q

what happens after cell adhesion to the endothelium

A

Adhering monocytes are stimulated by MCP-1 to cross endothelium and lodge in intima
Turn to macrophage once in tissue

33
Q

what molecules are involved the transient initial contact

A

E and P-selectin expressed on activated endothelium (not activated in normal circumstances)

34
Q

what molecules are involved the tighter binding

A

ICAM-1 and V-CAM1 present on activated endothelium, not under normal circumstances)

35
Q

what is a requirement for inflammation

A

Ligands present on leucocytes

Activated endothelium a requirement for inflammation

36
Q

how do platelets interact with monocytes

A

Adherent/activated platelets can recruit and inflame monocytes

37
Q

how are recruited leucocytes activated

A

Phagocytic cells can recognise, ingest and destroy many pathogens
These cells recognise pathogens damaged host molecules by means of cell surface receptors that can discriminate between the surface molecules displayed by pathogens and host cells
Can also recognise damaged host molecules
Effect is to activate macrophages by pathogens

38
Q

what are types of pattern recognition receptors

A

Macrophage mannose receptor: ligands: conserved carb structures
Scavenger receptors: ligand: anionic polymers, acetylated and oxidised LDL
Toll like receptors: Ligand: range of ligands for various TLRs
Opsonisation of pathogens (coating with circulating receptors) also important

39
Q

what proinflammatory cytokines are released from macrophages

A

(IL-1B, TNF-a, IL-6)

40
Q

what is atherosclerosis

A

build-up of plaque lining arteries

Involves 3 areas of pathogenesis
Endothelial cell dysfunction
Inflammation mediated by monocytes/macrophages)
Dysregulation of lipid metabolism

41
Q

what is atherogenesis

A

development of atherosclerotic plaque

42
Q

how does atherogenesis occur

A

damaged endothelium and lipid deposits
expose collagen - activate platelets or
produced cyto/chemokines, recruit monocytes to develop into macrophages and foam cells which further damages endothelium