Diseases Revision Notes

Key Definitions - Communicable Disease: A disease that can be passed from one person to another. Non-Communicable Disease: A disease that cannot be passed from one person to another Pathogen: A micro-organism that can cause disease (bacteria + viruses) Risk Factor: Substances or aspects of lifestyle that have been proven to be linked to causing disease Correlation: A link between diseases and lifestyle activities Causal Mechanism: A way of explaining how a factor of something influences another through a biological process Carcinogen: A substance that can cause cancer

The Difference Between Tumours: Tumors form when cell division gets out of control. There are two types of tumors. These are benign and malignant. The key difference between the two is that a benign tumor does not spread to organs and is not cancerous and a  malignant tumor does spread to organs (via blood) and is cancerous.

White Blood Cells: White blood cells help defend the


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