Barriers and non-specific defences Quiz
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5 questions, one answer each
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1. Which feature of the skin directly forms a physical barrier to pathogens?
- A. Sebum
- B. Keratinised dead cells
- C. Skin flora
- D. Sweat
2. What is the effect of histamine in inflammation?
- A. It constricts arterioles and reduces capillary permeability
- B. It destroys bacteria directly
- C. It dilates arterioles and increases capillary permeability
- D. It stimulates interferon production in bacteria
3. How does lysozyme destroy bacteria?
- A. It hydrolyses peptidoglycan in the cell wall, so cells burst by osmosis
- B. It blocks viral replication in host cells
- C. It denatures proteins at pH 2
- D. It engulfs the bacteria by endocytosis
4. What does interferon do?
- A. It engulfs viruses
- B. It makes neighbouring cells produce antiviral proteins
- C. It breaks down bacterial cell walls
- D. It traps pathogens in the airways
5. A patient on broad-spectrum antibiotics develops a gut infection with an opportunistic pathogen. Which is the best explanation?
- A. Stomach acid has become more alkaline
- B. Mucus is no longer secreted
- C. Interferon has destroyed the gut cells
- D. Gut flora have been killed, so there is less competition for nutrients and space