Immunology and Public Health (Non Specific and Specific Immune System)

Question 1

What is immunity?

Answer 1

The ability of the body to resist infection by a pathogen or to destroy the organism if it succeeds in invading and infecting the body

Question 2

What is the first line of defence?

Answer 2

Epithelial cells

Question 3

What is the second line of defence against disease?

Answer 3

Chemical- sweat, tears, mucus, saliva

Question 4

Explain the inflammatory response.

Answer 4

Skin is broken
Mast cells release histamine which attracts cytokines.
Histamine causes increased capillary permeability and vasodilation
Cytokines attract antimicrobial proteins and clotting elements and phagocytes to be delivered to and accumulate at the site of infection
Phagocytes accumulate and engulf pathogens
Phagocytes release more cytokines which stimulate the specific immune response.

Question 5

What do phagocytes and NK Cells release and what does it stimulate?

Answer 5

Cytokines to stimulate the specific immune response

Question 6

How do phagocytes destroy pathogens?

Answer 6

They recognise surface antigen molecules on pathogens and destroy them by phagocytosis.

Question 7

Explain phagocytosis.

Answer 7

1. Phagocytes surround the bacterium
2. A vacuole forms around the bacterium and it is trapped inside the phagocyte.
3. Lysosomes inside the phagocyte fuse with the vacuole containing the bacterium
4. The bacterium is digested by enzymes from lysosomes
5. Breakdown in products is released

Question 8

What do NK cells do?

Answer 8

Release a protein which makes pires in the membrane of a pathogen allowing signal molecule to pass into the cell to induce the pathogen to produce self destructive enzymes in apoptosis

Question 9

What is immune surveillance?

Answer 9

A range of white blood cells constantly circulate the body monitoring the tissues. If tissues become damaged or invaded, cells release cytokines which increase blood flow resulting in phagocytes and T lymphocytes cells accumulating at the site of infection/ damage.

Question 10

What happens sometimes when phagocytes capture a pathogen?

Answer 10

Phagocytes will display fragments of the pathogen’s antigens on their surface. Other infected. Cells in the body also become antigen presenting cells

Question 11

Why do antigen presenting cells do?

Answer 11

Activate T Lymphocytes to divide by mitosis to produce clones of lymphocytes which move to the site of infection under the direction of cytokines. Some of the clones of T lymphocytes remain in the body as memory cells.