Non-specific immunity: The body's first and second lines of defence that respond the same way to all pathogens, regardless of type, without requiring previous exposure.
Phagocyte: A type of white blood cell that can engulf and digest pathogens by the process of phagocytosis.
Phagocytosis: The process by which a phagocyte detects a pathogen, surrounds it with its cell membrane, takes it inside the cell, and destroys it using digestive enzymes.
Lysozyme: An antimicrobial enzyme found in tears, saliva, and mucus that destroys bacterial cell walls.
Mucus: A sticky secretion produced by cells lining the respiratory and digestive tracts. Traps pathogens, dust, and debris and prevents them from reaching deeper tissues.
Cilia: Microscopic hair-like projections on cells lining the airways. Beat rhythmically to sweep mucus (with trapped pathogens) upward and away from the lungs.
This definitions covers Key Definitions within Human Defense Systems - Non-specific for GCSE Biology. Physical and chemical barriers, white blood cell responses, inflammatory response It is section 10 of 16 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.
Practice questions for Human Defense Systems - Non-specific
Which part of the body acts as the main physical barrier to prevent pathogens entering?
Explain how mucus and cilia in the airways protect against pathogens.
Quick recall flashcards
What is phagocytosis?
The process by which white blood cells (phagocytes) engulf and digest pathogens or foreign particles.
What is sebum?
An oily substance produced by sebaceous glands in the skin that creates an acidic environment on the skin surface, inhibiting bacterial and fungal growth.