Y11 Diseases and immunity
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This document defines key terms related to disease transmission and the immune system. It explains that pathogens can transmit diseases through direct or indirect contact. The body has mechanical, chemical, and cellular defenses against pathogens, including white blood cells that distinguish self from non-self and produce antibodies. Vaccination exposes the body to harmless antigens to trigger antibody production and develop immunological memory for long-term protection. Both active and passive immunity are described, with active immunity resulting from infection or vaccination and producing memory cells, while passive immunity involves acquiring antibodies without memory cell development.
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Y11 Diseases and immunity
- 2. LO: • Define the key words: – Pathogen – Transmissible disease – Active immunity – Passive immunity • Explain the process of vaccination • Explain the specificity of antigens • State the types of body defence
- 3. Pathogen = Disease causing organism
- 4. Transmissible disease • Is a disease in which the pathogen can be passed from one host to another Diseases can be transmitted: • direct contact, e.g. through blood or other body fluids, • indirectly, e.g. from contaminated surfaces or food, from animals, or from the air
- 6. Defence systems • Mechanical barriers: - skin and hairs in the nose • Chemical barriers: – mucus and stomach acid • Cells: – phagocytosis and antibody production by white blood cells can be enhanced by vaccination
- 8. • Discuss the importance of: – hygienic food preparation, – good personal hygiene, – waste disposal and – sewage treatment in controlling the spread of disease
- 9. White blood cells : phagocytes, lymphocytes – Distinguish between self and non-self cells – Produce antibodies • Molecules on the surfaces of cells that are not found in other organisms = antigens (e.g. blood system) • The response of lymphocytes to the presence of a foreign antigen = immune response
- 10. • Lymphocytes – Produce antibodies; memory cells – antibodies lock on to antigens leading to direct destruction of pathogens, or marking of pathogens for destruction by phagocytes – each pathogen has its own antigens, which have specific shapes, so specific antibodies which fit the specific shapes of the antigens are needed • Phagocytes – phagocytosis
- 12. • Memory cells – Remain circulating in the body for a long time – If the same antigen is reintroduced a few weeks or months later, memory cells divide rapidly and develop into plasma cells – Basis of immunological memory – Last for many year, lifelong,
- 13. Phagocytosis
- 15. Immunity
- 16. • Active immunity – defence against a pathogen by antibody production in the body – is gained after an infection by a pathogen, or by vaccination • Passive immunity – short-term defence against a pathogen by antibodies acquired from another individual, e.g. mother to infant – No memory cells are produced – Important for new-borns: get all antibodies from the mother
- 17. Vaccination process of vaccination: • harmless pathogen given which has antigens • antigens trigger an immune response by lymphocytes which produce antibodies • memory cells are produced that give long- term immunity
- 18. Autoimmune diseases • some diseases are caused by the immune system targeting and destroying body cells • Type 1 diabetes