immune system defence
Overview
This lesson explores the intricate mechanisms by which the human body defends itself against pathogens and harmful substances. We will differentiate between non-specific (innate) and specific (adaptive) immunity, examining the various cellular and molecular components involved in each. Understanding these defence systems is crucial for comprehending disease resistance and immunological disorders.
Non-Specific (Innate) Immunity: First and Second Lines of Defence
Innate immunity provides immediate, general protection against a wide range of pathogens. It does not involve immunological memory and is present from birth. **First Line of Defence:** These are physical and chemical barriers that prevent pathogens from entering the body. * **Physical Barriers:**...
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Key Concepts
- Pathogen: A disease-causing microorganism or agent.
- Antigen: A molecule, often a protein or polysaccharide, that can trigger an immune response.
- Antibody: A Y-shaped protein produced by plasma cells in response to an antigen, capable of binding specifically to that antigen.
- Phagocytosis: The process by which phagocytes engulf and digest foreign particles, pathogens, or dead cells.
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Exam Tips
- →Clearly differentiate between innate and adaptive immunity, providing specific examples for each line of defence. Use terms like 'specificity', 'memory', and 'speed of response'.
- →For humoral immunity, focus on the role of B cells, plasma cells, and the various mechanisms by which antibodies act (neutralisation, opsonisation, agglutination, complement activation).
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