Infection & ResponseDefinitions
Key Definitions
Part of Human Defense Systems - Non-specific — GCSE Biology
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 13 of 18 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.
Topic position
Section 13 of 18
Practice
19 questions
Recall
22 flashcards
Key Definitions
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 white blood cell (such as a neutrophil or macrophage) that can engulf and digest pathogens by the process of phagocytosis.
Phagocytosis: The process by which a phagocyte surrounds a pathogen with its cell membrane, engulfs it into a vacuole (phagosome), and destroys it using digestive enzymes from lysosomes.
Lysozyme: An antimicrobial enzyme found in tears, saliva, mucus, and sweat that destroys bacterial cell walls by breaking down peptidoglycan.
Inflammation: A localised response to tissue damage or infection, characterised by redness, heat, swelling, and pain. Caused by vasodilation and increased capillary permeability, allowing more white blood cells to reach the site.
Mucus: A sticky secretion produced by goblet 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 epithelial cells lining the airways. Beat rhythmically to sweep mucus (with trapped pathogens) upward and away from the lungs.
Neutrophil: The most numerous type of white blood cell; the first to arrive at an infection site. Short-lived but highly effective phagocytes that engulf and destroy bacteria rapidly.