Non-specific defences of the human body against pathogens
I can describe defences of the human body against pathogens including physical, chemical and microbial defences, and phagocytosis.
Non-specific defences of the human body against pathogens
I can describe defences of the human body against pathogens including physical, chemical and microbial defences, and phagocytosis.
Lesson details
Key learning 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.
- 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.
Common misconception
All blood cells protect us against pathogens.
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.
Keywords
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.
Equipment
None required.
Content guidance
- Depiction or discussion of sensitive content
Supervision
Adult supervision recommended
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Video
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Starter quiz
6 Questions
Exit quiz
6 Questions
a scab forming to prevent infection
eyes producing tears that contain enzymes to break down pathogens
the microbiota
