The Defence System

Question 1

What is a pathogen?

Answer 1

A disease causing organism

Question 2

Examples of pathogenic organisms include…

Answer 2

Some bacteria, fungi and viruses

Question 3

Two lines of defence

Answer 3

• The general defence system

* The specific defence system

Question 4

Antibodies are part of what system?

Answer 4

Specific defence system

Question 5

What is part of the general defence system?

Answer 5

Skin
Mucus
Chemicals
White blood cells
Platelets

Question 6

What is an antigen?

Answer 6

An antigen is a ‘foreign’ substance that causes a white blood cell to produce an antibody

Question 7

Where are antigens found?

Answer 7

Antigens are found on the surface of pathogens and transplanted organs (eg. heart)

Question 8

Where are antigens found?

Answer 8

On the surface of pathogens and transplanted organs

Question 9

What is a lymphocyte?

Answer 9

A lymphocyte produces antibodies which attach to specific antigens

Question 10

What is an antibody?

Answer 10

A protein made by white blood cells (lymphocyte) that recognises and attaches to specific antigen

Question 11

What is a monocyte?

Answer 11

A monocyte engulfs a pathogen and destroys it

Question 12

What is the process in which monocytes engulf pathogens?

Answer 12

Phagocytosis

Question 13

What are memory cells?

Answer 13

Memory cells are made by your body when you make antibodies

Question 14

What is the function of memory cells?

Answer 14

Memory cells speed up the response time when an invader of the same type returns in the future

Question 15

What is immunity

Answer 15

Immunity is the protection against infection

Question 16

What is induced immunity?

Answer 16

Induced immunity is protection against infection using antibodies

Question 17

What are the two types of induced immunity

Answer 17

1) Active induced immunity

2) Passive induced immunity

Question 18

What is active induced immunity

Answer 18

• you make the antibodies and the memory cells
• Can be natural (made during infection)
• Can be artificial (vaccination)
• Long-term

Question 19

What is passive induced immunity

Answer 19

• antibodies given to you (you do not make antibodies or memory cells)
• short-term
• Natural (given to a child in the womb before birth or in breast milk after birth)
• Artificial (given by injection of antibodies example antitetanus)

Question 20

What is immunisation

Answer 20

Immunisation involves giving a person a vaccination or an injection of antibodies to protect against infection

Question 21

What is a vaccination

Answer 21

A vaccine is a dead or damaged pathogen that triggers antibody production

Question 22

How do vaccinations work

Answer 22

Vaccination tricks lymphocytes into producing antibodies and memory cells so that if the real pathogen attacks in the future antibodies are produced very quickly to destroy it before It can do damage

Question 23

How does the general defence system fight fever

Answer 23

• High temperatures denature enzymes in the pathogen

- The pathogen dies

Question 24

Where are b-lymphocytes produced

Answer 24

In the bone marrow

Question 25

What is the function of b-lymphocytes

Answer 25

To produce antibodies

Question 26

Where are T-lymphocyte produced

Answer 26

In the bone marrow

Question 27

Four types of T cells

Answer 27

Helper T cells
killer T cells
suppressor T cells
memory T cells

Question 28

Function of helper T cells

Answer 28

Trigger the production of b cells and killer T cells

Question 29

Function of killer T cells

Answer 29

They destroy

• virus infected cells
• tumour cells (cancer)
• foreign cells (this is why transplants are rejected)

Question 30

Function of suppressor T cells

Answer 30

They switch off the immune response after the antigen (pathogen) has been destroyed

Question 31

Function of memory T-cells

Answer 31

These remember the antigens

Question 32

Autoimmune diseases

Answer 32

1) rheumatoid arthritis (where joints are attacked)
2) Multiple sclerosis MS (where the myelin sheet of nerve cells is attacked)
3) Psoriasis (where the skin is attacked)

Question 33

What are allergies

Answer 33

Allergies occur when antibodies are made against material that should not be antigenic

Question 34

Example of allergies

Answer 34

Hayfever (the body reacts to pollen which is harmless)