Disease & Immunity

Question 1

What are pathogens?

Answer 1

Disease causing organisms

Question 2

Give examples of pathogens

Answer 2

• Fungi
• Bacteria
• Viruses

Question 3

How do viruses make you sick?

Answer 3

They invade living, normal cells and use those cells to multiply and produce other viruses like themselves. They kill, damage, or change the cells and make you sick

Question 4

How do pathogens cause illness?

Answer 4

• Through direct damage of tissues

- The production of toxins

Question 5

How are pathogens transmitted? Give examples of each. There are 5.

Answer 5

• Respiratory droplets e.g. Influenza
• Faecal oral ( food and water borne) e.g. Salmonella
• Insect vector e.g. Malaria
• Breaks in skin e.g. HIV through needle punctured
• Sexual transmission e.g. STDs such as HIV

Question 6

What did Semmelweis do?

Answer 6

• Discovered the importance of hand washing/hygiene in hospitals

Question 7

How do you reduce the spread of Cholera and salmonella?

Answer 7

• Kitchen hygiene

- Cook food thoroughly

Question 8

How do you reduce the spread of malaria (insect vector)?

Answer 8

• Mosquito nets
• Use of repellent
• Draining in breeding grounds

Question 9

How do you reduce respiratory droplets and contagious diseases?

Answer 9

• Isolation
• Use of face masks
• Use of tissues to catch sneezes etc.
• Catch it, bin it, kill it campaign

Question 10

How do you reduce sexual transmission?

Answer 10

• Use condoms

Question 11

How do you reduce illness from break in skin?

Answer 11

• Do not reuse needles

Question 12

How have the developent of vaccines impacted the deaths due to infectious diseases?

Answer 12

• The discovery of antibiotics and development of vaccines have resulted in big decrease in the percentage of deaths due to infectious diseases.

Question 13

Role of skin

Answer 13

• Provides a protective barrier against injury and hazardous substances

Question 14

Role of mucus and cilia

Answer 14

• The respiratory system is lined with a mucous membrane that secretes mucous
• The mucous traps smaller particles like pollen or smoke
• Hairlike structures called cilia line the mucous membrane and move the particles trapped in the mucous out of the nose

Question 15

What do lysozomes do?

Answer 15

Lysozomes in tears and saliva are natural antiseptic

Question 16

What does hydrochloric acid do?

Answer 16

Kills most microbes in your stomach that could potentially be dangerous

Question 17

What does acidic sweat do?

Answer 17

Sweat is acidic which inhabits the growth of many microbes

Question 18

What does commensal bacteria do?

Answer 18

This ‘friendly’ bacteria in your gut out competes invading microbes

Question 19

What do scabs and blood clots do?

Answer 19

Prevents dirt from entering a wound

Question 20

What are the types of white blood cells and what do they do?

Answer 20

• Phagocytes~Engulf and digest pathogens. This process is called phagocytosis
• Lymphocytes~Lymphocytes produce special chemicals called antibodies that target and destroy specific pathogens and neutralise specific toxins released by pathogens

Question 21

What is immunity?

Answer 21

When a pathogen enters the body, the white blood cells ‘rememeber’ it so if it gets in the body again, they will produce a large amount of antiboies in a short amount of time(before it can cause severe illness)

Question 22

What is the process of vaccination?

Answer 22

• The immunisation or vaccination involves giving someone a dead or weakened form of the relevant white blood cels to produce antibodies against the pathogen.
• If the live pathogen does enter your body in the future, the white blood cells will remember it and quickly produce large amounts of the antibody to eliminate it.

Question 23

What is an antigen?

Answer 23

• A toxin or other foreign substance which creates an immune response in the body, especially the production of antibodies.

Question 24

What is an antibody?

Answer 24

• Y shaped proteins with antigen binding sites at the end of eah arm
• Antibodies can only bind to an antigen whose shape fits intot the binding sites