Immune System I

Question 1

What are the roles of the immune system?

Answer 1

Protection from disease, Waste disposal, Surveillance (Recognition/Activation)

Question 2

What are the 2 types of defence organisations?

Answer 2

Innate and adaptive immunity

Question 3

Describe innate immunity

Answer 3

Pre-existing (from birth), natural, unchanging response

Question 4

Describe adaptive immunity

Answer 4

Specific response, acquired immunity, develops after birth

Question 5

What is blood divided into?

Answer 5

Mostly plasma, tiny buffy coat (of leukocytes/platelets), rest erythrocytes

Question 6

Describe the immediate response to an extracellular infection

Answer 6

Phagocytosis, complement activation, mast activation
Vasodilation, Vascular permeability, Extravasation
Acute inflammation

Question 7

Briefly describe the role of neutrophils

Answer 7

First line of defence, leads to phagocytosis

Question 8

What is the function of mast cells?

Answer 8

Release of histamine causes redness/swelling

Release vasoactive compounds

Question 9

What is extravasation?

Answer 9

Tethering of cells

Question 10

Which cells are involved in acute inflammation?

Answer 10

Phagocytes: Neutrophils, monocytes, macrophages, dendritic cells, eosinophils
Mast cells

Question 11

Which molecules are involved in acute inflammation?

Answer 11

Complement - Plasma protein cascade

Cytokines

Question 12

Name examples of cytokines involved in acute inflammation

Answer 12

TNF-a, IL-1, IL-6

Question 13

Describe TNF-a

Answer 13

Allows plasma to enter tissues causing swelling, proteins/antibodies, potent activator of neutrophils

Question 14

Describe IL-1

Answer 14

Stimulates adherence (leads to fever/fatigue effects hypothalamus)

Question 15

Describe IL-6

Answer 15

Acts directly on liver, inhibits release of albumin

Question 16

Which processes are involved in acute inflammation

Answer 16

Phagocytosis, Opsonisation, Chemotaxis

Question 17

What is opsonisation?

Answer 17

Protective system constantly produced, present in bodily fluid/blood, coats/labels cells so they’re easier to phagocytose

Question 18

What are the early events during an innate response?

Answer 18

Phagocytosis, Cell/protein activation, Inc vascular permeability

Question 19

What type of responses are stimulated by receptors?

Answer 19

Secretion, Adherence, Chemotaxis, Phagocytosis

Question 20

What do receptors do?

Answer 20

Respond to specific ligands, different cells respond differently to same ligand

Question 21

What are the types of receptors found on phagocytes?

Answer 21

Pathogen associated molecular patterns (PAMPs)
Toll-like receptors
Fc receptors

Question 22

Describe PAMPs

Answer 22

Sugars and lipids

Question 23

Describe toll-like receptors

Answer 23

Bacterial lipoproteins, peptidoglycan, flagellin, unmethylated DNA
- Found on the surface of the cell so deal with extracellular foreign activity

Question 24

Describe Fc receptors

Answer 24

Bind to Fc region of antibodies

Question 25

What are cytokines?

Answer 25

Low molecular weight proteins secreted to regulate intensity/duration of immune response

Question 26

Name examples of molecules that secrete cytokines

Answer 26

Fibroblasts, endothelial cells

Question 27

What are chemokines?

Answer 27

Cytokines that mediate chemotaxis

Question 28

What are the key cytokines involved in innate immunity?

Answer 28

TNF-a, IL-1, IL-6

Question 29

Describe the modes of action by cytokines

Answer 29

Autocrine, paracrine and endocrine

Question 30

Describe the systemic effects of cytokines

Answer 30

In brain - Fever, fatigue, loss of appetite | In liver - Acute phase proteins synthesised eg C-reactive proteins

Question 31

What are C-reactive proteins?

Answer 31

Secreted by liver binding to microbial surfaces and dna/other material from cells

Question 32

What is the difference between primary and secondary lymphatic tissues?

Answer 32

Primary - Bone marrow/thymus, all else secondary (lymph fluid, antigens drained from tissues to secondary lymphoid tissues to initiate immune response using lymphocytes/antigens

Question 33

Describe the role of the spleen

Answer 33

Has macrophages, its a secondary sensory tissue vital to remove microorganisms from blood

Question 34

What are the types of adaptive immunity?

Answer 34

Specificity, Diversity, Memory, Self-tolerance

Question 35

Describe specificity

Answer 35

Provided by T/B cells

Question 36

Describe diversity

Answer 36

Recognise many different antigens

Question 37

Describe memory

Answer 37

Better response with each exposure

Question 38

Describe self-tolerance

Answer 38

Discriminate between self/non-self cells

Question 39

What are the different regions of an antibody?

Answer 39

``` Fab region (Epitope binding) Fc region (Receptor binding) ```

Question 40

Define an antigen

Answer 40

Any substance that binds specifically to an antibody

Question 41

Define an epitope

Answer 41

Region of an antigen that is recognised by an antibody

Question 42

Define allergen

Answer 42

Antigen that elicits an allergic reaction | Note: So those with allergies have high levels of IgE AB

Question 43

What are the different classes of antibodies and their roles?

Answer 43

IgM - Activates complement, first antibody made, B-cell receptor IgD - B-cell receptor IgG - Transferred across placenta, binds to phagocytes, activates complement, most common class in blood IgE - Binds to mast cells, involved in allergic response IgA - Found in mucosal secretions

Question 44

Further describe IgG immunoglobins

Answer 44

Maternal antibodies transferred to fetus through circulation up until birth until child develops own immunity, binds to phago by Fc receptors

Question 45

Further describe IgA immunoglobins

Answer 45

In mucosal secretions, found in different secretory tracts eg bronchial tract/GI tract

Question 46

What are the different antibody functions?

Answer 46

Neutralisation - To neutralise toxins before it has effect on cells Agglutination - Forming large clump of pathogen cells to phagocytose together Complement activation Opsonisation - Labelling through for phagocytosis NK cell activation - Antibodies trigger NK cells, Fc region on AB binds to fc receptor on NK cells, release perforins (produce pores in cells)