Question

It is essential that phagocytes react to invading pathogens (foreign) and do not react toward the body's own tissues. How is this done?

a) Phagocytes always attack both foreign and self-tissues.
b) Phagocytes use pattern recognition receptors (PRRs) to distinguish between foreign and self-tissues.
c) Phagocytes rely on antibodies to differentiate between foreign and self-tissues.
d) Phagocytes only attack self-tissues to protect against autoimmune diseases.

Answer 1

Phagocytes differentiate between foreign invaders and the body's own tissues using pattern recognition receptors (PRRs), which recognize pathogen-specific molecular patterns distinct from those found on host cells.

Step-by-step explanation:

To ensure that phagocytes react to invading pathogens and not to the body's own tissues, they use pattern recognition receptors (PRRs) to distinguish between foreign and self-tissues.

These PRRs are membrane-bound receptors that recognize pathogen-specific molecules such as bacterial cell wall components, bacterial flagellar proteins, or pathogen-associated molecular patterns (PAMPs) which are expressed by viruses, bacteria, and parasites but differ from molecules on host cells. Thus, the correct answer to the question is 'b) Phagocytes use pattern recognition receptors (PRRs) to distinguish between foreign and self-tissues'.