Immune Response

Question 1

What is the body’s first line of defence

Answer 1

The innate immune system

Question 2

Name some features of the innate immune system

Answer 2

Skin
Mucus
Cilia
Tears/saliva
Stomach acid

Question 3

What is an antigen

Answer 3

A large molecule on the surface of a cell/virus that can be used to determine if the cell/virus is self or non-self

Question 4

What is the body’s second line of defence

Answer 4

The adaptive immune system

Question 5

Name some features of the adaptive immune system

Answer 5

Phagocytosis
fever
Blood clotting
Inflammation
Natural Killer Cells

Question 6

How does phagocytosis occur

Answer 6

Dendritic and macrophage cells engulf the pathogen and hold it internally in a vesicle. The then release enzymes to break down the pathogen

Question 7

What is an opsonin

Answer 7

Any molecule that enhances phagocytosis by marking a antigen for an immune response

Question 8

How does blood clotting work

Answer 8

Platelets release thromboplastin which turns prothrombin into active thrombin. Thrombin turn Fibrinogen into fibrin fibres which cross over to form a plug

Question 9

How can blood clotting go wrong

Answer 9

By forming an embolism

Question 10

What are the symptoms of inflammation

Answer 10

Heat
Swelling
Redness
Pain

Question 11

Why does inflammation occur

Answer 11

Mast cells and Basophils release histamine which causes vasodilation attracting white blood cells

Question 12

What is the body’s third line of defence

Answer 12

Specific immunity

Question 13

Name the features of specific immunity

Answer 13

Humoral immunity

Cell mediated immunity

Question 14

What happens in antigen presentation

Answer 14

Dendritic and macrophage cells bind to the pathogen and enter the lymph where they present the non-self antigens to specific B and T helper cells

Question 15

What happens in clonal expansion

Answer 15

The t-helper releases cytokines which causes the B cell to multiply rapidly. Some develop into plasma cells and others become memory cells

Question 16

How are antibodies produced

Answer 16

The new B plasma cells produce antibodies to attack
the antigen. The antibodies are released into the blood. Antibody-antigen complexes are then destroyed by phagocytes and/or expelled from the body in urine. Remaining B plasma cells and antibodies only remain in the blood for a few weeks.

Question 17

What happens to the B memory cells

Answer 17

They remain in the lymph to help identify the pathogen more quickly next time there is an infection

Question 18

List the four ways antibodies work

Answer 18

Clump pathogens together
Neutralise toxins by releasing antitoxins
Digest bacterial enzymes (lysis)
Coat pathogens in protein to label them as foreign

Question 19

What is cell mediated immunity

Answer 19

T cells are cloned to produce t killer, helper and memory cells. T killer cells locate diseased body cells and kill them to kill the pathogen

Question 20

What can t helper cells do

Answer 20

Release cytokines to stimulate phagocytosis

Question 21

What types of immunity are there

Answer 21

Innate - born with it

Acquired

Question 22

How can you acquire immunity

Answer 22

Actively - exposure to infection, vaccination

Passively - mothers antibodies, injected antibodies

Question 23

Why are most vaccines given in multiple doses

Answer 23

First dose induces primary immune response but secondary immune response is more effective

Question 24

How can vaccines be ineffective

Answer 24

On a pathogen that mutates very frequently

They don’t fully stimulate an immune response

Question 25

Ethical considerations around vaccination

Answer 25

Cost vs efficacy
Protection of the individual compared to herd immunity
The right to autonomy in mandatory programmes
Side effects