Topic 2: Fundamentals of the Immune System

Question 1

Innate and adaptive: physical barriers

Answer 1

Innate: skin, mucous, cilia, hair, flushing mechanisms
Adaptive: nil

Question 2

Innate and adaptive: physiological barriers

Answer 2

Innate: pH, temp
Adaptive: nil

Question 3

Innate and adaptive: diversity and specificity

Answer 3

Innate: non-specified
Adaptive: highly specific, customised responses

Question 4

Innate and adaptive: typical speed on onset

Answer 4

Innate: quick
Adaptive: slow at first exposure, but quicker subsequent exposures

Question 5

Innate and adaptive: ability to adapt

Answer 5

Innate: no
Adaptive: yes

Question 6

Innate and adaptive: immunological memory

Answer 6

Innate: no
Adaptive: yes

Question 7

Innate and adaptive: key immune cells involved

Answer 7

Innate: mast, dendritic, microphages, macrophages, natural killer
Adaptive: B-cells –> antibodies, T-cells:helper, killer. memory, suppressor

Question 8

Innate and adaptive: weapons used

Answer 8

Innate: enzymes, acid, interferons, cytokines, complement
Adaptive: antibodies and killer T-cells

Question 9

Innate and adaptive: soluble (humeral) factors/molecules

Answer 9

Innate: cytokines, complement, interferons
Adaptive: antibodies

Question 10

What are some functions of the immune system?

Answer 10

maintain cellular, tissue, system and whole body homeostasis

Question 11

What is homeostasis?

Answer 11

maintenance of optimal body/system/organ/cell function

Question 12

What aspects are regulated through homeostasis at a cellular and tissue level?

Answer 12

Cellular: cell volume, osmolarity, electrolyte concentration, intracellular pH, membrane potential, concentrations of substances (PRRs)
Tissue: cell number and composition, tissue architecture, concentration of substances, pH, temperature, osmolarity (PRRs)

Question 13

What must a pathogen do to cause disease?

Answer 13

1. gain access to body
2. attach to/enter host cells
3. reproduce while avoiding the immune system

Question 14

What is the primary system of the immune system and what does it do?

Answer 14

Lymphatic system

• housing system for immune cells
• transport

Question 15

What are the organs of the immune system?

Answer 15

lymphatic tissues

Question 16

What are the primary lymphatic tissues?

Answer 16

Bone marrow: produces all immune cells

Thymus: matures T-cells

Question 17

What are the secondary lymphatic tissues?

Answer 17

Lymphatic vessels: passively drains lymph from tissue
Lymph nodes: monitor lymph for infection, house lymphocytes
Mucosa: traps potential infectants, mast cells
Spleen: house mature T- and B cells, filters RBC

Question 18

What are the different cells of the immune system?

Answer 18

Erythroid: RBC, platelets
Myeloid: microphage (neutrophil, eosinophil, basophil), monocytes –> macrophages, mast cells, dendritic cells
Lymphoid: large lymphocytes (natural killer), small lymphocytes (B-cells, T-cells)

Question 19

What does myeloid lineage include?

Answer 19

microphages (neutrophil, eosinophil, basophil), monocytes –> macrophages, mast cells, dendritic cells

Question 20

What are macrophages?

Answer 20

migrate to vascularised tissue and break down cell walls with enzymes

Question 21

What are mast cells?

Answer 21

found in areas with high amounts of blood, prominent near internal/external barriers, present in tissue trauma

Question 22

What are dendritic cells?

Answer 22

tissue-resident, introduces pathogens to immune system

Question 23

What are the cells of adaptive immunity?

Answer 23

T-cells, (helper, cytotoxic, suppressor), B-cells (plasma cells), dendritic cells

Question 24

What are the large lymphocytes?

Answer 24

natural killer cells - kill pathogens

Question 25

What are the small lymphocytes?

Answer 25

B-cells, T-cells

Question 26

B-cells

Answer 26

B cells: produced + mature in bone marrow, plasma --> antibodies, memory

Question 27

Helper-T cells

Answer 27

secrete cytokines, amplify antibody production

Question 28

Cytotoxic T-cells

Answer 28

kill cells, enzymes, live in thymus

Question 29

Suppressor T-cells

Answer 29

dampen/suppress immune response

Question 30

Memory T-cells

Answer 30

recognise original invading antigen, immunological memory

Question 31

What are the molecules of the innate and adaptive immune systems?

Answer 31

Innate: cytokines (chemokines, interleukins, interferons), complement Adaptive: antibodies

Question 32

Cytokines

Answer 32

- used for communication between immune cells | - cell activation and deactivation, up- or down- regulate synthesis

Question 33

What are the types of cytokines?

Answer 33

Chemokines: guide immune cells to infection site, 'chemical trail' Interleukins: communication between leucocytes Interferson: produced and released by host cells in response to presence of pathogens

Question 34

What is the complement system?

Answer 34

proteins circulating within the blood stream and break down cell walls, facilitates inflammation

Question 35

What are the key defence mechanisms?

Answer 35

Innate: first line of defense, cellular Adaptive: second line of defense, highly specific

Question 36

What are the physical barriers of the first line of defence?

Answer 36

skin, mucous membranes, hair, cilia

Question 37

What are the mechanical barriers of the first line of defence?

Answer 37

vomiting, coughing, sneezing, urinating, defecating

Question 38

What are the physiological barriers of the first line of defence?

Answer 38

pH, temperature

Question 39

What are the chemical barriers of the first line of defence?

Answer 39

nitric oxide, catabolic enzymes, cytotoxic proteins, acid, lysosomal enzymes (saliva, ear wax, sebum, sweat glands), physical properties (ie sticky wax, mucous)

Question 40

What is the innate cellular immune response?

Answer 40

non specific, no immunological memory, deals with pathogens the same way every time

Question 41

What are the cells of innate cellular immunity?

Answer 41

macrophages, mast cells, natural killer, dendritic

Question 42

Eosinophils

Answer 42

degrade pathogens with cytotoxic substances, explosive

Question 43

Neutrophils

Answer 43

principal phagocytic cell, collateral damage, suicide by apoptosis

Question 44

Basophils

Answer 44

similar to eosinophils and mast cells, explosive

Question 45

What is the adaptive immune system?

Answer 45

highly specific, immunological memory

Question 46

What is immunological memory?

Answer 46

faster and stronger subsequent responses - antibodies produced in secondary response = greater affinity for antigen

Question 47

How is the immune response triggered? (pathogens)

Answer 47

1. pathogens invade host 2. pathogens release PAMPs 3. PAMPs recognised by PRRs in innate system 4, PAMPs captured by innate immune cells and presented to other immune cells

Question 48

What are PAMPs?

Answer 48

pathogen-associated molecular patterns, induce inflammation, identify pathogens to innate immune cells

Question 49

What are PRRs?

Answer 49

pattern-recognition receptors, surface receptors on resident innate immune and parenchymal cells that response to PAMPs, trigger response of other immune cells

Question 50

What are inducers of inflammation?

Answer 50

PAMPs, DAMPs, pH, hyperoxia, obesity/overweight, lifestyle factors

Question 51

What are some examples of when immunity goes wrong?

Answer 51

allergies, arthritis, anaphylactic shock, cancer, septic shock, transplant rejection, HIV

Question 52

How is the immune response triggered? (no pathogens)

Answer 52

1. tissue damage 2. DAMPs released by distressed/damaged/dying cells 3. DAMPs recognised by PRRs in innate system 4. DAMPs captured by innate cells