Science

Question 1

What mechanisms exist to protect the body against micro-organisms?

Answer 1

1. Physical barriers - skin, cilia, stomach acidity, flora
2. Innate immune response - reacts to foreign antigen with no previous exposure, rapid and non-specific, no memory
3. Adaptive immune response - retains memory, subsequent exposure results in a superior response

Question 2

How does the innate immune system protect against micro-organisms?

Answer 2

Pattern recognition receptors (PPRs) are present on the surface of immune cells such as neutrophils, mast cells, dendritic cells and NK cells.
These PPRs (e.g. TLRs) respond to pathogen-associated molecular patterns (PAMPS), which are unique cellular constituents that are not found in vertebrate and include - cell surface proteins, glycoproteins, LPS in Gram neg cell walls, components found in Gram +ve cell walls e.g. lipotechoic acid