Year 11 - Science
Non-specific defences of the human body against pathogens
Defences against pathogens, the human immune system and vaccination
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
This unit explores the body's defences and immune response against pathogens, disease prevention, and vaccines. It covers plant defence responses, and disease detection, and evaluates scientific applications, considering personal, social, economic, and environmental implications.
Lesson Summary
You will learn to describe defences of the human body against pathogens including physical, chemical and microbial defences, and phagocytosis.
Key Notes
- The human body has defences against infection that work against all pathogens (are not targeted at specific pathogens).
- Physical defences include the skin, hairs and cilia.
- Chemical defences include tears, saliva and stomach acid.
- Microbial defences are provided by microorganisms on, and in, our bodies that compete against pathogens.
- White blood cells called phagocytes are part of the immune system and engulf and destroy pathogens by phagocytosis.
Vocabulary To Learn
- pathogen: A microorganism that causes disease.
- immune system: A system of defences in the body, including white blood cells, which protects against pathogens.
- platelets: Components of the blood which help blood to clot and seal wounds.
- white blood cell: A type of cell in the blood that is part of the immune system and responds to pathogens.
- phagocytosis: When a white blood cell engulfs, digests and destroys a pathogen.
Common Mistakes To Avoid
- All blood cells protect us against pathogens.
3 Quick Questions (With Answers)
1. Explain the scientific idea in this lesson using two key points.
The human body has defences against infection that work against all pathogens (are not targeted at specific pathogens). Physical defences include the skin, hairs and cilia.
2. Define this scientific word and use it in context. 'pathogen'
A microorganism that causes disease. Include the word in a full scientific explanation, not as a single label.
3. Correct this common scientific misunderstanding.
Mistake: All blood cells protect us against pathogens. Correction: White blood cells are part of the immune system that protects us against pathogens. Red blood cells transport oxygen to cells. Platelets are not cells, but they do help to protect against pathogens by helping to seal wounds.
More Lessons In This Unit
- Evaluating the global use of vaccination Study Guide
- Immunity and vaccination Study Guide
- Light microscopy: observing and identifying microorganisms Study Guide
- Plant defences against disease Study Guide
- Plant defences, and identifying plant diseases Study Guide
- Responses of the human immune system to specific pathogens Study Guide
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