Human Defence System

Question 1

What is immunity?

Answer 1

The resistance to an infection.

Question 2

What is a pathogen?

Answer 2

A disease causing organism.

Question 3

What are the two defence systems?

Answer 3

General defence system and Specific defence system.

Question 4

What is the 1st line of the general defence system?

Answer 4

Skin, Clotting, Sebum, Lysozyme, Mucus.

Question 5

What is the function of the skin in the general defence system?

Answer 5

Acts as a barrier & prevents pathogens from entering the body.

Question 6

What is the function of clotting in the general defence system?

Answer 6

Platelets in the blood form a clot, preventing the open wound from allowing pathogens.

Question 7

What is the function of sebum in the general defence system?

Answer 7

Skin produces sebum & the chemical in sebum kills pathogens.

Question 8

What is lysozyme?

Answer 8

An enzyme in saliva and tears that helps destroy pathogens’ cell walls.

Question 9

What is the function of mucus in the general defence system?

Answer 9

Lungs & nose are lined with mucus. Traps pathogens in its sticky viscous.

Question 10

What are cilia?

Answer 10

Tiny hairs in the nose that trap pathogens & move them out of the body.

Question 11

What is the role of acid in the general defence system?

Answer 11

Found in stomach & vagina, they kill bacteria due to low pH.

Question 12

What is the second line of the general defence?

Answer 12

White blood cells, Defence proteins, Inflammation.

Question 13

What are white blood cells?

Answer 13

Phagocytes and Macrophages.

Question 14

What is a phagocyte?

Answer 14

Surrounds, engulfs & destroys bacteria.

Question 15

What is a macrophage?

Answer 15

A large phagocyte that kills bacteria in the lymphatic system.

Question 16

What are defence proteins?

Answer 16

Complement and Interferons.

Question 17

What are complement proteins?

Answer 17

A set of proteins that destroy bacteria.

Question 18

What are interferons?

Answer 18

A set of proteins that prevent viruses from reproducing & spreading.

Question 19

What is inflammation?

Answer 19

Chemicals released by damaged cells causing redness, heat & discomfort, attracting more white blood cells.

Question 20

What is the specific defence system?

Answer 20

Designed to attack particular pathogens.

Question 21

What are monocytes?

Answer 21

Type of white blood cell produced in the red bone marrow, released into the bloodstream & lymphatic system.

Question 22

What are lymphocytes?

Answer 22

Produced in the red bone marrow & engulf infected body cells containing antigens.

Question 23

What are antigens?

Answer 23

Foreign molecules that stimulate the production of antibodies.

Question 24

What is an antibody?

Answer 24

Proteins produced by white blood cells in response to the presence of antigens.

Question 25

What is the relationship between antigens and antibodies?

Answer 25

An antigen is displayed on the surface of a pathogen, stimulating antibody production specific to that antigen.

Question 26

How do antibodies work?

Answer 26

They prevent bacteria/viruses from entering and trigger the stimulation of defence proteins.

Question 27

What is induced immunity?

Answer 27

The stimulation of monocytes and lymphocytes to get rid of specific antigens.

Question 28

What is active immunity?

Answer 28

The production of antibodies by lymphocytes in response to a specific antigen.

Question 29

What is natural active immunity?

Answer 29

Occurs when lymphocytes produce antibodies in response to infection from the environment. ## Footnote Example: Resistance to a common cold.

Question 30

What is artificial active immunity?

Answer 30

Occurs when lymphocytes produce antibodies in response to a pathogen administered through vaccines.

Question 31

What is passive immunity?

Answer 31

Transfer of antibodies from one organism to another.

Question 32

What is natural passive immunity?

Answer 32

When a baby receives antibodies from its mother through the placenta or breast milk.

Question 33

What is artificial passive immunity?

Answer 33

When a person receives an injection of antibodies made in another organism.

Question 34

What is vaccination?

Answer 34

The administration of a non-disease-causing dose of the pathogen or part of a pathogen which stimulates active immunity.

Question 35

What is immunisation?

Answer 35

The protection against pathogens by the injection of antibodies.

Question 36

What is the difference between artificial and natural immunity?

Answer 36

Artificial is the administration of antibodies & natural is the production of antibodies.

Question 37

What are B-lymphocytes?

Answer 37

Mature in the bone marrow before moving to the lymph nodes and attack by producing antibodies.

Question 38

What are plasma B cells?

Answer 38

Produces antibody molecules which bind to pathogens and mark them for destruction.

Question 39

What are memory B cells?

Answer 39

They live in the body and respond if the same antigen enters again, enabling immunity.

Question 40

What are the functions of memory B cells?

Answer 40

Produces more antibodies, quicker production of antibodies, and produces antibodies in response to very little antigen.

Question 41

What are T lymphocytes (T cells)?

Answer 41

Move from the bone marrow & mature in the thymus gland, attacking cells by invading antigens.

Question 42

What are the 4 types of T-lymphocytes?

Answer 42

Helper T cells, Killer T cells, Suppressor T cells, Memory T cells.

Question 43

What are helper T cells?

Answer 43

Recognise antigens & stimulate the production of B cells & Killer T cells.

Question 44

What are killer T cells?

Answer 44

Attack cells containing a foreign antigen and secrete perforin to destroy infected cell membranes.

Question 45

What are suppressor cells?

Answer 45

Stops the immune response after the pathogen has been destroyed.

Question 46

What are memory T cells?

Answer 46

Triggers the production of B & T cells much quicker if a pathogen enters the body.

Question 47

Where do B lymphocytes mature?

Answer 47

Bone marrow.

Question 48

Where do T lymphocytes mature?

Answer 48

Thymus.

Question 49

Why does active immunity result in longer lasting immunity?

Answer 49

As memory T cells are produced and better able to respond.

Question 50

How do vaccines give immunity?

Answer 50

Stimulate antibody production.

Question 51

What are the two types of induced immunity?

Answer 51

Active and passive.

Question 52

What are two organs specific to the immune system?

Answer 52

Thymus and lymph nodes.

Question 53

Name a group of WBCs other than lymphocytes.

Answer 53

Monocytes.

Question 54

What WBCs produce antibodies?

Answer 54

B-lymphocytes.

Question 55

What part of a virus is recognised by antibodies?

Answer 55

Antigens.

Question 56

What is the function of antibodies?

Answer 56

Recognise antigens.

Question 57

What is the difference between active and passive immunity?

Answer 57

Active lasts longer than passive.