11 - Immunity

Question 1

What is a pathogen?

Answer 1

A foreign agent which introduces foreign proteins into the body (antigens), which should not normally be there

Question 2

What are four examples of pathogens?

Answer 2

1) Bacteria
2) Protozoa
3) Fungi
4) Parasites

Question 3

What is immunity?

Answer 3

The ability of the body to resist damage from foreign substances and internal threats

Question 4

What are the two categories of immunity?

Answer 4

1) Innate/non-specific
2) Adaptive/specific

Question 5

What part of a pathogen does the body recognise as non-self?

Answer 5

Antigens. One pathogen will have multiple antigens.

Question 6

What is innate/non-specific immunity?

Answer 6

The way that the body reacts to a pathogen, regardless of what it is

Question 7

What are 4 examples of innate/non-specific immunity?

Answer 7

Physical barriers
Inflammation
Chemical mediators
White blood cells (macrophages)

Question 8

What is adaptive/specific immunity?

Answer 8

The ability to recognise a specific antigen on a pathogen, and mount a particular response

Question 9

What are the two types of adaptive/specific immunity?

Answer 9

Cell-mediated immunity
Antibody-mediated immunity

Question 10

When is innate/non-specific immunity present from?

Answer 10

Present from birth.

Question 11

Does innate/non-specific immunity have memory? What does this entail?

Answer 11

No memory.
Response will be the same during repeated exposures to the same pathogen.

Question 12

What is the first line of defence in innate/non-specific immunity? What are some examples? (4)

Answer 12

Physical barriers
- skin/mucous membrane
- saliva/tears
- acidic environments (stomach, urinary tract, vagina)
- cilia

Question 13

What is the second line of defence in innate/non-specific immunity? (4 examples)

Answer 13

Chemical mediators
- Histamines
- Cytokines
- Complement system
- Interferons

Question 14

What is the role of histamines in non-specific immunity?

Answer 14

Promote vasodilation and increased vascular permeability
Attract white blood cells and stimulate phagocytosis

Question 15

What is the role of cytokines in non-specific immunity?

Answer 15

Regulate intensity and length of the immune response

Question 16

What is the role of the complementary system in non-specific immunity?

Answer 16

Stimulate lysis of invading pathogen cells

Question 17

What is the role of interferons in non-specific immunity?

Answer 17

Stimulate anti-viral activity

Question 18

Where are white blood cells/phagocytes produced?

Answer 18

Bone marrow and lymphatic tissue

Question 19

What are 6 cells of the white blood cells of innate immunity?

Answer 19

Neutrophils
Macrophages
Basophils
Eosinophils
Natural killer cells
B&T lymphocytes

Question 20

What is the role of neutrophils in innate/non-specific immunity?

Answer 20

Be first on the scene of acute inflammation
Begin phagocytosis

Question 21

What is the role of macrophages in innate/non-specific immunity?

Answer 21

Most effective phagocytes
Help activate cells of the adaptive/specific immune system

Question 22

What is the role of basophils in innate/non-specific immunity?

Answer 22

Immunosurveillance
Produce histamines in allergies

Question 23

What is the role of eosinophils in innate/non-specific immunity?

Answer 23

Respond mostly to parasitic infection and allergies

Question 24

What is the role of natural killers cells in innate/non-specific immunity?

Answer 24

Cause lysis of virus-infected cells or cancer cells

Question 25

What is the role of B and T lymphocytes in innate/non-specific immunity?

Answer 25

Carry out adaptive immune responses

Question 26

What is inflammation?

Answer 26

A local tissue response to damage (e.g. pathogens, cuts/abrasions), aiming to prevent further pathogen entry and remove the debris/invading pathogen.

Question 27

What are the 4 features of inflammation?

Answer 27

Redness Heat Swelling Pain

Question 28

What is fever?

Answer 28

Generalised response of the body to tissue damage and infection

Question 29

What role does a high temperature play in innate/non-specific immunity?

Answer 29

Increase antimicrobial substances Decrease microbial growth Increase body reactions which help with tissue repair

Question 30

What are 7 steps of an inflammatory response?

Answer 30

1) Bacteria enters tissue 2) Tissue damage occurs 3) Chemical mediators released 4) White blood cells attracted to the area, increased permeability and blood floow 5) Increased number of white blood cells and chemical mediators at site of tissue damage 6) Bacteria are contained, destroyed and phagocytised 7) If bacteria gone, tissue repair begins. If not, return to no. 3

Question 31

Does adaptive/specific immunity have memory? What does this entail?

Answer 31

Has memory. Able to remember previous encounters with a pathogen and mount a quick response

Question 32

What is adaptive/specific immunity mediated by?

Answer 32

Lymphocytes (B and T)

Question 33

How it adaptive/specific immunity acquired?

Answer 33

Through exposure to pathogens during the lifetime

Question 34

What antigens does cell-mediated immunity work well against?

Answer 34

Intracellular (e.g. viruses)

Question 35

What antigens does antibody-mediated immunity work well against?

Answer 35

Extracellular antigens

Question 36

What are the two stages in antibody production? When do they occur? How will the second differ from the first?

Answer 36

Primary response - when B-cell first exposed to antigen Secondary response - later exposure to the same antigen - response will be faster and more intense

Question 37

What are the effects of antibodies in antibody-mediated immunity

Answer 37

Inactivates the antigen Binds antigens together Facilitate phagocytosis

Question 38

What are the stages of antibody-mediated immunity?

Answer 38

1) B-cells are activated by the presence of a foreign antigen 2) T-cells assist B-cells to differentiate into plasma cells and memory B-cells 3) Plasma cells release antibodies 4) Antibodies travel in the blood and target specific antigens 5) Antibodies destroy pathogens 6) Memory B-cells stick around for the next exposure to the same pathogen

Question 39

What does it mean if something is cytotoxic?

Answer 39

It is toxic to the cell

Question 40

What role does the spleen have to play in immunity?

Answer 40

The spleen destroys defective red blood cells

Question 41

Where are T-cells produced?

Answer 41

The thymus

Question 42

What are the stages of cell-mediated immunity?

Answer 42

1) Antigen-presenting cells display antigens on the cell surface of a macrophage 2) Antigen bound to an MCH Class II molecule 3) Processed antigen presented to a helper T-cell for recognition 4) Co-stimulation occurs by CD4 glycoprotein/cytokines 5) Macrophage secretes cytokines (interleukin-1), stimulates helper T-cell to secrete interleukin-2 6) Helper T-cell divides to form daughter cells 7) Daughter cells will divide again if exposed to the same antigen 8) Increased no. of helper T-cells can facilitate the activation of B-cells/effector T-cells

Question 43

What is active immunity? Give an example of natural and artificial acquisition.

Answer 43

When immunity is provided by the body's own immune system Natural: natural exposure Artificial: vaccination

Question 44

What is passive immunity? Give an example of natural and artificial acquisition.

Answer 44

When immunity is transferred from one person/animal to another Natural: Maternal antibodies transferred through placenta/breastmilk Artificial: Antibodies from another person are injected