Defence System

Question 1

Define pathogen

Answer 1

An organism that causes disease

Question 2

How is the defence system divided?

Answer 2

General defence system and specific defence system

Question 3

What is the function of the general defence system?

Answer 3

Acts as a barrier against all pathogens attempting to gain entry into the body

Question 4

Name some body parts that make up the first line of the defence

Answer 4

• Skin
• Respiratory Tract
• Digestive Tract
• Reproductive Tract

Question 5

What is the defensive function of the skin?

Answer 5

• Physical barrier
• Sebaceous gland produces chemicals to kill bacteria
• Clotting prevents entry of pathogens

Question 6

What is the defensive function of the respiratory tract?

Answer 6

• Lined with cilia and mucous
• Traps pathogens

Question 7

What is the defensive function of the digestive tract?

Answer 7

HCI in the stomach kills pathogens

Question 8

What is the defensive function of the reproductive tract?

Answer 8

Mucous and lactic acid trap pathogens

Question 9

Name some body parts that make up the second line of defence

Answer 9

• Phagocytic white blood cells
• Inflammation
• Defence protein

Question 10

What is the defensive function of the phagocytic white blood cells?

Answer 10

Engulf and destroy microorganisms

Question 11

What is the defensive function of inflammation?

Answer 11

Swelling, redness, heat, and pain attract white blood cells

Question 12

What are defence proteins?

Answer 12

Proteins that destroy viruses and pathogens

Question 13

What is the defensive function of the defence proteins?

Answer 13

Proteins that destroy viruses and pathogens

Question 14

Give an example of a defence protein and its function

Answer 14

Interferon – Prevents viral multiplication

Question 15

What is the specific defence system?

Answer 15

Attacks against particular pathogens by the use of monocytes and anitobodies

Question 16

Name some organs of the specific defence system

Answer 16

• Thymus
• Spleen
• Lymph nodes
• Tonsils

Question 17

Define antibody

Answer 17

A protein made in response to an antigen

Question 18

Define antigen

Answer 18

A foreign protein that causes the production of antibodies

Question 19

What is the relationship between monocytes and macrophages?

Answer 19

Monocytes develop into macrophages that digest pathogens

Question 20

Are monocytes and macrophages a feature of the general or specific defence system?

Answer 20

General defence system

Question 21

What are the two main types of lymphocytes?

Answer 21

B-cells and T-cells

Question 22

Are lymphocytes a feature of the general or specific defence system?

Answer 22

Specific defence system

Question 23

What is the name of a specific type of B-cell

Answer 23

Memory B-cells

Question 24

What is the function of the B-lymphocytes (B-cells)?

Answer 24

Recognise antigens and make specific antibodies in response

Question 25

Where are B-lymphocytes (B-cells) made?

Answer 25

Bone marrow

Question 26

Where are B-lymphocytes (B-cells) matured?

Answer 26

Bone marrow

Question 27

What is the function of memory B-cells?

Answer 27

Stay alive for many years and allow the body to recognise the antigen if it enters the body again, providing long term immunity

Question 28

What is the function of T-cells?

Answer 28

Do not produce antibodies but act in some way against bacteria and viruses

Question 29

Where are T-cells made?

Answer 29

Bone marrow

Question 30

Where are T-cells matured?

Answer 30

Thymus gland

Question 31

What are the four different types of T-cells?

Answer 31

* Helper * Killer * Suppressor * Memory

Question 32

What is the function of helper T-cells?

Answer 32

* Make interferons * Recognise antigens * Stimulate the production of B-cells to produce antibodies * Stimulate the production of killer T-cells

Question 33

What is the function of killer T-cells?

Answer 33

* Produces perforin which causes the membrane of infected cells and cancers to burst (lysis)

Question 34

What is the function of suppressor T-cells?

Answer 34

Turns off the immune response

Question 35

What is the function of memory T-cells?

Answer 35

Survive a long time to give long term immunity and can turn on quickly to stimulate the production of B-cells

Question 36

Define immunity

Answer 36

Ability to resist infection

Question 37

Define active immunity

Answer 37

Body produces antibodies

Question 38

Give an example of natural active immunity

Answer 38

Making antibodies in response to infections

Question 39

Give an example of artificial active immunity

Answer 39

Vaccines

Question 40

Define passive immunity

Answer 40

Antibodies are introduced to the body from an external source

Question 41

Give an example of natural passive immunity

Answer 41

From the mother across the placenta or mother's milk

Question 42

Give an example of artificial passive immunity

Answer 42

An injection of antibodies e.g. anti-tetanus shot

Question 43

Define vaccination

Answer 43

A small dose of a harmless pathogen which stimulates the production of antibodies e.g. MMR. Short term immunity

Question 44

Antibiotics are usually not given to a person suffering from a viral infection. Why?

Answer 44

They do not kill viruses

Question 45

Describe some functions of the lymphatic system

Answer 45

* Lymph nodes and the spleen contain high numbers of white blood cells like lymphocytes and monocytes * Vital in the response to foreign bodies * Some lymphocytes are produced and stored in the spleen * Lymph nodes filter foreign bodies that enter our body