This deep dive covers Second Line of Defence: Phagocytosis within Human Defense Systems - Non-specific for GCSE Biology. Physical and chemical barriers, white blood cell responses, inflammatory response It is section 7 of 16 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Second Line of Defence: Phagocytosis
If pathogens get past the body's barriers, phagocytes (a type of white blood cell) are the next line of defence. Phagocytes move to the site of infection and destroy pathogens by a process called phagocytosis.
- Detection — the phagocyte detects chemicals released by the pathogen and moves towards it
- Engulfing — the phagocyte surrounds the pathogen with its cell membrane and takes it inside the cell
- Digestion — enzymes inside the phagocyte break down and destroy the pathogen
This process is non-specific — phagocytes attack any pathogen, regardless of type. The same response happens whether the pathogen is a bacterium, a fungus, or a virus.
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.