3.1 Immune System

Question 1

Why do humans have an immune system?

Answer 1

To attack and destroy invaders that enter the body.

Question 2

Our immune system has 2 lines of defence. Name them.

Answer 2

1. First line of defence

2. Second line of defence

Question 3

Describe the 2 parts that make up the first line of defence.

Answer 3

Skin and the linings of the body’s internal systems.

mucus, cilia, stomach lining etc

Question 4

Describe the 2 parts that make up the second line of defence.

Answer 4

The second line has 2 parts

1. Innate = built - in response. The innate response is a quick and general response. Inflammation, blood/fluid rushes to the area. Macrophages engulf invaders indiscriminately. Redness, swelling, fever.
2. Acquired = slow and specific response, antibody production targets specific invaders and then invaders are remembered. Main players are B cells and T-cells

Question 5

What is a pathogen?

Answer 5

A pathogen is a disease-causing invader - makes you sick

Question 6

What is an infectious disease?

Answer 6

A disease caused when an organism enters the body.

Question 7

What are the 4 ways to transmit infectious diseases?

Answer 7

1. Direct contact
2. Indirect contact
3. Water and food
4. Animal bites

Question 8

Give an example of each of the 4 ways to transmit an infectious disease.

Answer 8

1. Direct contact - shaking hands or sharing drinking containers or mixing body fluids with an infected person
2. Indirect contact - being near an infected person who sneezes without covering his or her mouth.
3. Water and food -eating foods or drinking water that are infected
4. Animal bites - being bitten by an animal carrying the rabies virus

Question 9

Name parts of the body that belong to the first line of defence.

Answer 9

Skin, stomach acid, mucus, cilia tears, oil and sweat on skin

Question 10

Describe the Innate Immune Response.

Answer 10

• quick and general
• responds in the same way to every invader
  -first action is a flow of fluid, cells to site of infection
  - this causes swelling and redness
  (inflammation)
  -# and type of white blood cells increase in the area of inflammation

Question 11

What is a phagocyte?

Answer 11

a type of white blood cells, the biggest and baddest is the macrophage which engulfs and kills invaders

Question 12

What is the role of a phagocyte?

Answer 12

To fight infection by swallowing them

Question 13

Describe the Acquired Immune Response in general.

Answer 13

This is a highly specific attack on a pathogen OR antigen. Your body can do this in 2 ways:

1. B cells in action
2. T cells in action

Question 14

Describe the 2 ways your body can mount an attack on an invader (Acquired Immune Response)

Answer 14

1. B cells - they recognize antigens and then they make antibodies, specific to antigens.
   - Antibodies can either prevent pathogen from infecting cells OR the mark pathogen for destruction. At the same time, similar B cells are made to fight other antigens in body.
2. T cells - starts when pathogen or antigen is inside body. White blood cell recognizes invader and signals for T cells.
   - One type of T cell = helper T cell - it recognizes invader and activates the B cells.
   - B cells make antibodies which destroy
   invader.
   - when the attack is over, some antibodies
   remain in body to protect in the future.
   - Another T cell = killer T cell - can work by themselves to destroy invaders or with the other cells.

Question 15

What is an antigen?

Answer 15

A substance your body cannot recognize. Antigens are NON-LIVING particles or substance.
Anything your body recognizes as foreign.
Example: virus, splinter

Question 16

What is an antibody?

Answer 16

Specific proteins that fight specific invaders.

Tags for invaders so they can be destroyed.

Question 17

What is active immunity?

Answer 17

When your body remembers which antibodies should be used to attack a pathogen that has infected it before.

The antibodies are stored on B cells called memory cells that can be reactivated if the antigen or pathogen reappears.

Question 18

What did Joseph Lister do?

Answer 18

Learned about washing hands and sterilize their tools - aseptic surgery

Question 19

What did Mary Montagu do?

Answer 19

Put pus in a cut and created immunity to sell pox (in India)

Question 20

What did Edward Jenner do?

Answer 20

Infected an 8 year old with cow pox to give him immunity to small pox

Question 21

what is a leukocytes?

Answer 21

a white blood cell

Question 22

what are the two types of leukocytes?

Answer 22

phagocytes and lymphocytes

Question 23

what are lymphocytes?

Answer 23

T cells and B cells which kill pathogens with the help of helper T cells and produce antibodies against pathogens

Question 24

What are memory B cells?

Answer 24

help remember specific antigens for later

Question 25

What are helper T cells?

Answer 25

Help B cells to kill pathogens

Question 26

What is a cytotoxic/killer T cell?

Answer 26

kills pathogens after it has infected a body cell by destroying the whole cell

Question 27

what is an allergy?

Answer 27

over-sensitive reaction to something -releases histamine which leads to allergy symptoms

Question 28

what is an allergen?

Answer 28

foreign substance that causes an allergy

Question 29

what is an anaphylactic reaction?

Answer 29

a severe allergic reaction

Question 30

what is immunity?

Answer 30

resistance to a pathogen

Question 31

What are the four ways a pathogen can be transmitted?

Answer 31

1. direct contact 2. indirect contact 3. ingestion - food or water 4. animal or insect bite

Question 32

What are the four main types of pathogens?

Answer 32

1. Bacteria - antibiotics will work against these 2. Virus - immunization is effective for prevention, antiretroviral after the fact 3. Fungus - anti-fungal (usually a cream) 4. Parasite - various treatments