Question

What is the function of tears and saliva in the first-line defence system?

Options

• They engulf and digest bacteria through phagocytosis

• They alert nearby cells to resist viral replication

• They increase blood vessel permeability at infection sites

• They continuously wash away surface pathogens

Answer 1

Tears and saliva function in the first-line defence by continuously washing away surface pathogens from the eyes, mouth, and exposed mucous membranes. Additionally, saliva and tears contain lysozyme, which breaks down bacterial cell walls, providing both mechanical and chemical protection.