# Explain how the human body's non-specific defence systems and the immune system work together to protect the body when a bacterial pathogen enters through a cut in the skin.

> WJEC A-Level Biology (Wales) — 3.5 Human impact on the environment · Explain · 5 marks

## Mark scheme (5 marks)

1. The skin / blood clotting acts as a mechanical barrier to prevent pathogens entering (non-specific defence)
2. White blood cells detect the pathogen using receptors that identify antigens on the pathogen's surface
3. Phagocytes engulf and digest the pathogen (phagocytosis) using enzymes
4. Lymphocytes produce antibodies that are specific to / complementary to the antigen and bind to it to neutralise the pathogen
5. Memory cells remain after the infection so that if the same pathogen enters the body again, it can be destroyed more quickly

## Key terms

- [non-specific defence system](https://www.gradenine.co.uk/glossary/non-specific-defence-system)
- [immune system](https://www.gradenine.co.uk/glossary/immune-system)

## Related

- [Revision notes for WJEC A-Level Biology (Wales)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-how-the-human-body-s-non-specific-89fa08b3) · Published by Druglandscape Ltd.