What role do mucous membranes and cilia play in the body's defence against pathogens? (A) They cause cell death to seal off pathogens - HSC - SSCE Biology - Question 14 - 2011 - Paper 1

Mucous membranes and cilia are critical components of the immune system. They play a crucial role in the body’s defense by acting as barriers to pathogens. Specifically:

• Barrier Function: Mucous membranes line various cavities in the body and secrete mucus, which traps pathogens, dust, and other harmful particles. This prevents their entry into the body.

• Ciliary Action: Cilia are hair-like structures that move in a coordinated manner to push trapped pathogens and debris out of the respiratory tract. This action helps in clearing potential threats from the airways and helps keep the passages clear of pathogens.

Thus, the most accurate choice regarding their role is (B) They form part of a barrier preventing entry of pathogens.