5.1 Defence
mechanisms
,Defence mechanisms
• A range of layers of defence against pathogens
• Some are general and immediate e.g. skin, or phagocytosis
• Some are specific and slower but longer lasting e.g. cell mediated
response (T lymphocytes) and humoral response (B lymphocytes)
,Recognising our own cells
• All cells have specific molecules on their surface which have specifi
structures
• Proteins (antigens) most important as they have highly specific
tertiary structures
• These allow immune system cells to identify…
• Pathogens
• Non-self e.g. transplant tissue
• Toxins
• Abnormal body cells e.g. cancer
,
mechanisms
,Defence mechanisms
• A range of layers of defence against pathogens
• Some are general and immediate e.g. skin, or phagocytosis
• Some are specific and slower but longer lasting e.g. cell mediated
response (T lymphocytes) and humoral response (B lymphocytes)
,Recognising our own cells
• All cells have specific molecules on their surface which have specifi
structures
• Proteins (antigens) most important as they have highly specific
tertiary structures
• These allow immune system cells to identify…
• Pathogens
• Non-self e.g. transplant tissue
• Toxins
• Abnormal body cells e.g. cancer
,
