Immunity & Disease

Question 1

What is immunity?

Answer 1

It’s protection or defence against infections from:

• Bacteria
• Fungi
• Viruses
• Toxins
• Cancer
  ext. ..

Question 2

What are the 2 main pathways of the immune system?

Answer 2

• Innate

- Adaptive

Question 3

What is the innate immune system and give some examples…

Answer 3

The innate immune system is non-specific and is a protective mechanism even before infection:

• Skin, mucous membrane
• Phagocytic cells (Neutophils, macrophages, inflammation, fever)

Question 4

What is the adaptive immune system and give examples.

Answer 4

It’s a specific response such as cell mediated immunity and humoral immunity.
The cells in this system have memory such as T-cell and B-cells

Question 5

How does the skin protect our bodies from infection?

Answer 5

• Has an outer layer of keratin which is a mechanical barrier
• Dead skin cells constantly being sloughed off which makes it hard for invading bacteria to colonize
• Sweat and oils contain anti-microbial chemicals

Question 6

How do mucous membranes help protect us from infections?

Answer 6

-Normal flow of mucous wash bacteria and viruses off mucous membranes
For example:
-Cilia in the respiratory tract.
-Acid in the stomach+ vagina
-Enzymes in saliva and the eyes

Question 7

What are some chemical barriers in the prevention of infection in our bodies.

Answer 7

PROTEINS such as

• Complement, which works with other defence mechanisms of the body
• Interferons, which inhibit the replication of many viruses.

Question 8

Name some Granulocytes and their role in defence…

Answer 8

-Neutophils, Eosinophils, Basophils

Their role is to remove dead cells and micro-organisms.
They are attracted by an inflammatory response of damaged cells.

Question 9

Which cells are mainly responsible for phagocytosis?

Answer 9

Monocytes (macrophages)
They are in tissues and work as filters for trapping microbes.
They live longer than granulocytes and usually arrive later than granulocytes.

Question 10

List some non-specific responses to infections…

Answer 10

Macrophages release protein signals- interluekin-1 and interleukin-6:

• Fever
• Pain, swelling redness (promote blood flow and phagocytic cells to area.
• Acute phase protein release from liver (bind to bacteria and activate complement proteins)

Question 11

Which division of the immune system relies on antigens (specific substances found in foregn microbes) and Lymphocytes.

Answer 11

The Specific (ADAPTIVE) immune system.

Question 12

Name the types of LYMPHOCYTES.

Answer 12

T-CELLS: produced in bone marrow and matured in thymus

B-CELLS: produced in bone marrow and matured in bone marrow and concentrated in lymph nodes and spleen.

Question 13

Where are Lymphocytes produced?

Answer 13

They’re produced in Bone Marrow and matured in different areas:
T-CELLS: Thymus
B-CELLS: Bone marrow and concentrated in spleen and lymph nodes

Question 14

Why do lymphocytes circulate around the body (in lymph and blood)

Answer 14

To ensure they come into contact with pathogens and eachother.

Question 15

What is the role of B-Cells (lymohocytes)

Answer 15

They secrete antibodies (Humoral immunity and recognise pathogens outside cells)

Question 16

What’s the role of T-Cells (lymphocytes)

Answer 16

• CYTOTOXIC t-cells (CD8 MHC 1) directly attack invaders, and destroy antigens in system. And destroy microbes tagged by antibodies.
• T Helper Cells: Help B-Cells (CD4 MHC11)

Question 17

How do T-Cells recognise invaders?

Answer 17

They detect antigens by protein markers on the cell surface. If NOT self they will trigger an immune response.

They can also recognise microbes that have been tagged by antibodies (Cytotoxic T Cells)

Question 18

Name some different subtypes of Antibody produced by B-Cell Lymphocytes…

Answer 18

IgG
IgM
IgA
IgD
IgE

Question 19

Name some problems assosiated with the immune system.

Hint over/under active

Answer 19

• Immunodeficiency = prone to infections
• Overactive immune system = hypersensitivity reactions
• Failure to recognise self = autoimmune diseases

Question 20

What can make someone immunodeficient?

Answer 20

• Chemo / Drugs
• HIV
• Splenectomy
• Bone marrow dysfunction

Question 21

Give some examples of a hyperactive immune system…

Answer 21

• Allergies (Hypersensitivity)
• Auto-immunity
• Overreaction to pathogen

Question 22

Name some causes to secondary immunodeficiency…

Answer 22

• Malnutrition
• Burns
• Uremia
• Diabetes Mellitus
• Immunotoxic Medications
• Self medication of recreational drugs/alcohol
• AIDS

Question 23

What could be classed as a type 1 Hypersensitve immune reaction

Answer 23

Anaphylaxis/ Allergy

• Asthma
• Rhitinis (hay fever)
• Peanut allergy

Question 24

What is an autoimmune disease?

Answer 24

Failure of an organism in recognising it's own constituent as 'self'
For example:
-Coeliac Disease
-MS
-Hashimoto's Thyroiditis

Question 25

What term is used to describe the stimulation of the immune system to elicit adaptive immune response to prevent future infections.

Answer 25

Active Immunity/ Vaccination It depends on herd immunity

Question 26

Name some types of Vaccinations...

Answer 26

- Live (attenuated): MMR - Inactive: Hep B - Toxoid: Bacterial toxin, Diptheria - Conjugated: Antigen linked to protein carrier, Pneumococcal