Non Specific Response

Question 1

How does phagocytosis destroy pathogens?

Answer 1

1. Phagocytes (macrophages and neutrophils) engulf pathogens in a PHAGOSOME
2. Phagosome then fuses with a lysosome which has enzymes to digest it
3. Phagocyte then releases CYTOKINES which causes other phagocytes to move to the spot of infection, stimulating a specific immune response.

Question 2

What is the role/purpose of opsonin

Answer 2

• Binds to pathogens and tags them as FOREIGN so its easily recognisable to phagocytes.
• Phagocytes have receptors on their cell membrane that are complementary to opsonin (when it binds to opsonin, a pathogen is engulfed)

Question 3

Outline the process of inflammation.

Answer 3

1. At site of damage, mast cells and basophils release HISTAMINES
2. These chemicals cause blood vessels to dilate (vasodilation) producing local heat and redness.
3. Histamines also cause walls of capillaries to become leaky so plasma and white blood cells is forced out to desroy pathogens.

Question 4

How do fevers treat infections?

Answer 4

• Raise body temperature which slows the reproduction rate of pathogens so less damage is caused.
• Immune system works better at high temps
  If body is above 40C some enzymes will denature causing tissue damage.