Practice Questions
1.Define the term non specific defence
Non-specific defence mechanisms are the body’s general, immediate defences that work against any pathogen, not just one specific type.
2. Give one example of a non specific defence that protects us against pathogens.
Any one of the following from the table
| Part of body | How it protects us |
|---|---|
| Skin | Skin forms a protective barrier to stop pathogens from entering. If the skin is cut, the blood clots and dries to form a scab, sealing the wound and preventing pathogens from entering. The skin contains glands that secrete oils and sweat which contain antimicrobial chemicals. These chemicals will kill pathogens. |
| Nose | Nose contains both mucus and hairs which traps pathogens. |
| Trachea and Bronchi | Both trachea and bronchi contain goblet cells that secrete a sticky mucus and ciliated cells with cilia. The mucus traps dust and pathogens, whilst the cilia hairs waft the mucus and pathogens up to the top of the airways. Swallowing then takes the mucus and pathogens down the oesophagus into the stomach. Acid in the stomach will kill the pathogens. See the diagram below |
| Stomach | The stomach contains hydrochloric acid, which kills pathogens on food. |
3. Describe how phagocytes protect us against pathogens.
The phagocyte will engulf the pathogen and then use enzymes to break it down.