Ch 8 covers human health — common diseases (typhoid, pneumonia, malaria, amoebiasis), immunity (innate and adaptive), cancer, AIDS, and substance abuse.
Bacterial: typhoid (Salmonella), pneumonia (Streptococcus). Viral: common cold, AIDS (HIV). Protozoan: malaria (Plasmodium via Anopheles), amoebiasis (Entamoeba). Innate immunity: physical barriers (skin, mucus), phagocytes, NK cells, complement. Adaptive immunity: humoral (B-cells → antibodies) and cell-mediated (T-cells). Primary vs secondary immune response. Vaccination: memory cells formed.
Cancer: uncontrolled cell division due to oncogene activation or tumour suppressor inactivation. Benign (localised) vs malignant (metastasis). Causes: carcinogens (chemical, radiation), viruses (oncogenic). Detection: biopsy, MRI, CT. Treatment: surgery, radiation, chemotherapy, immunotherapy. AIDS: HIV (retrovirus) destroys helper T-cells (CD4⁺). Transmitted through blood, sexual contact. No cure; antiretroviral therapy.
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Vaccination introduces weakened, killed, or parts of a pathogen into the body. The immune system recognises the antigens and mounts a primary immune response, producing antibodies and memory B/T cells. When the actual pathogen attacks later, memory cells rapidly mount a strong secondary immune response (faster and stronger), preventing the disease. This is the basis of immunological memory.
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