EMS lectures 4,5,6,7 Flashcards Preview

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Flashcards in EMS lectures 4,5,6,7 Deck (51):
1

What cells are of lymphoid lineage

natural T killer cell, small lymphocytes, T cell, B cell and plasma cells

2

What cells are of myeloid lineage

megakaryocyte, RBC, mast cells, myeloblasts, thrombocytes, basophils, neutrophils, eosinophils, monocytes, macrophages

3

What are the 5 major components of the innate immune system

Pattern recognition receptors
antimicrobial peptides
cells
complement components
cytokines

4

what are Pattern recognition receptors

antigen recognition receptor
- specific
- 2 groups
- cell surface (transmembrane and intercellular receptors - TLR, NLR, RLR, CLR)
- Fluid phase soluble molecules = c-type lectin family (collectins)

Role in neutralisation of pathogen and recruitment of adaptive response

5

Role of cell in innate immune system
Macrophage

Phagocytose and kill bacteria
produce inflammatory cytokines

6

Role of cell in innate immune system
Natural Killer cells

kill foreign and host cells that have low levels of MHC+ self peptides

7

Role of cell in innate immune system
NK T cells

recognize lipid antigens of intracellular bacteria by CD1 and kill infected host cells

8

Role of cell in innate immune system
Neutrophils

phagocytose and kill bacteria, produce antimicrobial peptides

9

Role of cell in innate immune system
eosinophils

kill invading parasites

10

Role of cell in innate immune system
mast cells and basophils

release TNF, IL6, IFN

11

Role of cell in innate immune system
Epithelia cells

produce antimicrobial peptides,

12

What is the adaptive immune response

evolution in response to changing pathogen structures
- unique antigen receptor on each lymphocyte
- clonal expansion of lymphocyte

13

What are the primary lymphoid organs and what is their function

bone marrow and thymus

lymphocyte development and selection

14

what are the secondary lymphoid organs and what is their function

spleen
lymph nodes
mucosal surfaces

immune responses

15

What is the mechanism of antigen presentation

1) Antigen internalised and broken into peptides
2) peptides associated with class 2 molecules
3) presented on cell surge
4) peptides recognised as foreign by T helper Cells
5) activated T helper cells secrete cytokines for T and B cells

16

What is the Histocompatibility antigen
- what are the classes of histocompatibility antigen

- gycoprotiens expressed on mammalian cells that make us unique found on white cells
- Human Leucocyte antigen (HLA)
- coded for by MHC
- Class 1 - HLA-A,B,C
- Class 2 - HLA-DP,DQ,DR

17

What is the function of class 1 and class 2 MHC cells

T cells only see antigents associated with MHC proteins

Class 1 MHC presents peptides to cytotoxic T cells
Class 2 MHC presents peptides
to helper T cells

18

function of B cells

secrete antibodies (humeral immunity)

19

function of killer T lymphocytes

kill cells - cellular immunity

20

function of helper T lymphocytes

secrete cytokines, stimulate B and T lymphocytes

21

function of suppressor T lymphocytes

dampen down immune response

22

Inactivation of antigens by the binding of antibodies can occur how?

neutralisation - coating and blocking binding sites
agglutination of microbes
precipitation of dissolved antigens
(enhances phagocytosis)

activation of complement system - causes cell lysis

23

define immunosuppression

natural or artificial process turns off immune response

24

define immunodeficiency

lack of efficient immune system
(caused by immune suppression)

25

define hypersenstivity

undesirable reaction to an innocuous antigen in a pre senstized host with a normal immune system

26

what are the types of hypersensitivity?

1) igE mediated reaction
2) cytotoxic reaction
3) immune complex reaction
4) cell mediated reaction

27

features of type 1 hypersensitivty reaction

IgE mediated
realease of preformed mediator - histamine
synthesis of lipid mediator - leukotriene
- FAST onset, weal and flare
- common allergens - hay, pollen, bee stings
- assoicated disease- hay fever, allergic asthma

28

Explain Immunoglobulin E

IgE
Produces by plasma cells from class switched B cell
production controlled by IL4 and CD40L - CD40 reaction
- low serum levels

High affinity for IgE receptor (FCeRI)on mast cells and basophils

29

What does the preformed mediator do?
Histamine

stimulate irritant nerve receptors and smooth muscle contractions
increase vascular permiabiltiy

30

What does the preformed mediator do?
kallikrein

activate Bradykinin
(similar to histamine)

31

What does the preformed mediator do?
Tryptase

unknown

32

when are preformed mediators released in the type one sensitivity reaction?

in the early phase
during the degranulation of mast cells

33

What is the role of the eosinophils and basophils in the late phase type 1 reaction?

Basophils - degranulate and release preformed mediators

Eosinophils - release contents of Granules (cytotoxic proteins)
- major source of tissue damage
- attracted to sites of allergic inflammation by chemokines

T cells - continue reaction with production of cytokines

34

explain type 2 hypersensitivity reaction

cytotoxic
IgM (or IgG) initiated
activated compliment cascade --> lysis
aggregation of Ig --> phagocytosis

usually affects haemopoietic cells

Associated diseases
ABO incompatibility
Autoimmune anaemias
Platelet disorders

35

Explain type 3 hypersensitivity

Immune complex formed
FcR binds to C1q
Compliment activation generates activated complement fragments
C5a - attract neutrophils
C3b - opsonin
attempted phagocytosis of complexes = release of enzymes and free radicals

TISSUE DAMAGE = RESULT

36

EXPLAIN type 4 hypersensitivty

T cell mediated - CD4, MHC2
delayed reaction
Langerhans cells present NEOANTIGENS to T cells
T cells release cytokines
Macrophages recruited
Macrophages cause tissue damage

37

Explain T cell cytotoxicity

CD8 MHC1 - contact demerits
Antigen presented by APC

38

Explain Granulomatous reaction

Collection on inflammatory cells in tissues
release of cytokines by T cells cause initial response

Caused by
TB, leprosy, sarcoidosis, crohn's

39

Primary Causes of chronic inflammation

endogenous material
- necrotic adipose tissue
- uric acid crystals

exogenous material
- implanted prosthesis
- sutures
- asbestos fibres

Autoimmune
- SLE
- rheumatoid arthritis

Primary Granulomatous
- Sarocoidosis
- Crohns

Infections
- TB
- Leprosy
- some viral infections

40

How does acute inflammation progress to chronic

give an example

Most commonly supprative acute inflammation
- forms abscess
- walls thicken
- granulation and scaring
- recurrent inflammation leads to chronic

e.g. cholecystitis - call bladder inflammation from stones

41

What are the morphological features of chronic inflammation

infiltration by mononuclear cells (macrophage, lymphocytes, plasma cells)
- tissue distruction
- healing by fibrosis

42

Role of the macrophage in chronic inflammation

Increase inflammation - stimulating immune system
- release cytokines which recruits monocytes
- proliferate and immobilise in damaged tissue
- debride damaged tissue with proteases inducing angiogenesis and granulation

43

what is leukocyte extravasion

the recruitment of monocytes through the endothelium of the blood vessels into the damaged area of tissues

44

What is granulation tissue

new connective tissue and blood vessels that form on surface of wound during healing

- fibroblasts deposit collagen
- aim to repair by replacement of injured tissues with fibrous tissues

stimulated by macrophage debridement of damaged cells

45

What is fibrosis

formation of excess fibrous connective tissue during repair

fibroma - if from 1 cell line
macrophage induced

46

What is granulomatous inflammation

aggregation of macrophages, lymphocytes and histiocytic giant cells (aka langhans type giant cells)

often with caseous necrotic centre (= caseous epitheliod granuloma)

47

what are histiocytic giant cells

formed when macrophages are unable to digest material

- multinucleated >100

48

What are granulomatous diseases

Bacterial - TB, Leprosy
Parasitic - schistosomiasis
Fungal - Cryptococcus
Synthetic material - silicosis
Unknown - sarcoidosis, crohn's

49

What is chronic inflammation response to MI?

Myocardial fibrosis

50

how is inflammation involved in atheroma formation

macrophages adhere to epithelium and recruit other cells

51

How does inflammation in MS present?

plasma cells and t lymphocytes are found in white matter because macrophages have broken down myelin