Human Health and Disease
Class 12 Biology · Biology · Chapter 7
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हिंदी (आधार)
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Accountancy
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اردو (اختیاری)
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Mathematics
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हिंदी (आधार)
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संस्कृतम् (केन्द्रिकम्)
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Physics
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हिंदी (ऐच्छिक)
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संस्कृत (ऐच्छिक)
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Physics
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हिंदी (ऐच्छिक)
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اردو (کور)
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Chemistry
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Urdu Elective
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Computer Science
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Chemistry
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Fine Art · Painting
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हिंदुस्तानी संगीत (गायन / वादन)
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Informatics Practices
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Accountancy
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Biotechnology
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Accountancy
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सृजनात्मक लेखन और अनुवाद
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Business Studies
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हिंदुस्तानी संगीत (तबला / पखावज)
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Economics
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Economics
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History
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History
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History
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Geography
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Geography
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Geography
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Psychology
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Home Science
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Home Science
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Summary
This chapter examines human health, disease and the body's defence mechanisms. It defines health and discusses common human diseases caused by pathogens, including bacterial (typhoid, pneumonia), viral (common cold), protozoan (malaria caused by Plasmodium, amoebiasis), fungal (ringworm) and helminthic (ascariasis, filariasis) infections, along with their symptoms, life cycles and preventive measures. The immune system is described in detail, distinguishing innate immunity (physical, physiological, cellular and cytokine barriers) from acquired immunity (humoral or antibody-mediated and cell-mediated). The structure of antibodies, types of immunoglobulins, primary and secondary immune responses, active and passive immunity, and the basis of vaccination and immunisation are explained. Allergies, autoimmunity and the role of the lymphoid organs (thymus, bone marrow, spleen, lymph nodes) are covered. AIDS, caused by the Human Immunodeficiency Virus (HIV), its transmission, mode of action on helper T-cells, diagnosis and prevention are detailed. Cancer is explained in terms of cell-cycle deregulation, oncogenes, proto-oncogenes, metastasis, and methods of detection and treatment. The chapter ends with drugs and alcohol abuse, covering opioids, cannabinoids, coca alkaloids, tobacco, their effects, addiction, dependence and the importance of prevention and rehabilitation.
Common diseases and pathogensImmunity: innate and acquiredVaccination and immunisationAIDS and HIVCancerDrugs and alcohol abuse
Key terms
Pathogen
A disease-causing organism such as a bacterium, virus, protozoan, fungus or helminth.
Innate immunity
Non-specific defence present from birth, including physical, physiological, cellular and cytokine barriers.
Acquired immunity
Pathogen-specific immunity characterised by memory, comprising humoral and cell-mediated responses.
Antibody
A Y-shaped protein (immunoglobulin) produced by B-lymphocytes that specifically binds an antigen.
Metastasis
The spread of cancer cells from the primary tumour to distant sites in the body.
Antigen
A foreign molecule that triggers an immune response and binds specifically to antibodies.
Extra questions & answers
Try one from this chapter
Malaria is caused by the protozoan: