Chapter Summary
Human Health & Disease deals with the concept of health, types of diseases (infectious and non‑infectious), immunity (innate and adaptive), vaccination, common human infections (bacterial, viral, protozoan, helminthic, fungal), allergies, autoimmune disorders, cancer, and drug/alcohol abuse. It emphasizes prevention, public health measures, diagnostics, and control strategies including vector management and herd immunity.
Innate vs Adaptive
Vaccines
Infectious Diseases
Allergy & Autoimmunity
Cancer
Substance Abuse
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50 Questions & Answers
1) Define health.
A state of complete physical, mental and social well‑being, not merely absence of disease.
2) What is disease?
Any condition that impairs normal functioning of the body.
3) Differentiate innate and adaptive immunity.
Innate: non‑specific, immediate, no memory (barriers, phagocytes, complement). Adaptive: specific, slower on first exposure, has memory (B & T cells).
4) Name primary lymphoid organs.
Bone marrow and thymus (sites of lymphocyte maturation).
5) Name secondary lymphoid organs.
Lymph nodes, spleen, tonsils, Peyer’s patches, MALT.
6) What are the components of innate immunity?
Physical/chemical barriers, cellular defenses (phagocytes, NK cells), inflammation, complement system, interferons.
7) Distinguish humoral and cell‑mediated immunity.
Humoral: antibodies from B cells; Cell‑mediated: T cells (helper, cytotoxic) targeting infected/abnormal cells.
8) What are antibodies? Name classes.
Immunoglobulins produced by B cells. Classes: IgG, IgM, IgA, IgE, IgD.
9) Define antigen, epitope and hapten.
Antigen: foreign molecule eliciting response; Epitope: antigenic determinant; Hapten: small molecule antigenic only when attached to carrier.
10) What is opsonization?
Coating of pathogens by antibodies/complement to enhance phagocytosis.
11) What is active vs passive immunity?
Active: immune response after infection/vaccination; Passive: ready‑made antibodies transferred (e.g., maternal IgG, antiserum).
12) Define herd immunity.
Community‑level protection when a high proportion is immune, reducing transmission.
13) Types of vaccines with examples.
Live attenuated (MMR), inactivated (polio IPV), subunit/recombinant (HBsAg), toxoid (tetanus), conjugate (Hib), mRNA/viral vector (platform concept).
14) What is adjuvant?
Substance added to vaccines to enhance immune response (e.g., alum).
15) What is hypersensitivity?
Excessive immune reactions; Type I (IgE‑mediated allergy), II (cytotoxic), III (immune complex), IV (delayed, T‑cell mediated).
16) Define allergy and allergen.
Allergy: IgE‑mediated immediate hypersensitivity; Allergen: harmless antigen triggering allergic response (e.g., pollen, dust mites).
17) Role of histamine in allergy.
Released from mast cells causing vasodilation, bronchoconstriction, itching and mucus secretion.
18) What is autoimmunity? Give examples.
Immune response against self; examples: rheumatoid arthritis, type 1 diabetes, multiple sclerosis.
19) What are monoclonal antibodies?
Identical antibodies produced by hybridoma technology; used in diagnostics and therapy.
20) What is ELISA?
Enzyme‑Linked Immunosorbent Assay used to detect antigens/antibodies (e.g., HIV screening).
21) Name the causative agent and mode of transmission of typhoid.
Salmonella typhi; feco‑oral route via contaminated food/water.
22) What is the diagnostic test for typhoid?
Widal test (antibodies against O/H antigens) and blood culture in early stage.
23) Name the causative agent of pneumonia (bacterial) and its symptoms.
Streptococcus pneumoniae; fever, chills, chest pain, cough with sputum, breathing difficulty.
24) Causative agent and transmission of common cold.
Rhinoviruses; droplets, contact with contaminated surfaces.
25) Pathogen, vector and organ affected in malaria.
Plasmodium spp.; vector female Anopheles; infects liver and RBCs causing periodic fever.
26) Name malarial species causing malignant tertian malaria.
Plasmodium falciparum.
27) What is the definitive and intermediate host in malaria?
Mosquito is definitive host (sexual phase), human is intermediate host (asexual phase).
28) Pathogen and transmission of amoebiasis.
Entamoeba histolytica; feco‑oral via contaminated food/water.
29) What causes ascariasis and its prevention?
Ascaris lumbricoides (roundworm); sanitation, washing vegetables, proper disposal of feces, deworming.
30) Filaria pathogen and symptoms.
Wuchereria bancrofti/Brugia malayi transmitted by Culex mosquitoes; chronic inflammation of lymph vessels → elephantiasis.
31) Ringworm causative agent and favorable condition.
Dermatophyte fungi (Microsporum, Trichophyton); thrives in warm, moist skin folds.
32) What are vectors? Give examples.
Organisms transmitting pathogens between hosts (e.g., mosquitoes, sandflies, ticks).
33) Prevention and control of vector‑borne diseases.
Eliminate breeding sites, insecticide sprays, bed nets, repellents, window screens, community sanitation.
34) Causative agent of tuberculosis and transmission.
Mycobacterium tuberculosis; airborne droplets from infected individuals.
35) Name the test and vaccine related to TB.
Tuberculin (Mantoux) test for exposure; BCG vaccine provides protection in children.
36) Pathogen and high‑risk cells in AIDS.
HIV targets CD4+ T helper cells, macrophages and dendritic cells leading to immunodeficiency.
37) Modes of HIV transmission.
Unprotected sex, contaminated needles, transfusion of infected blood, mother‑to‑child (pregnancy, delivery, breastfeeding).
38) Prevention/management of AIDS.
Safe sex, screened blood, sterile needles, ART (antiretroviral therapy), education and stigma reduction.
39) What is the difference between benign and malignant tumours?
Benign: localized, slow growth, non‑invasive; Malignant: invasive, metastasize via blood/lymph.
40) Define oncogenes and tumour suppressor genes.
Oncogenes: mutated/overexpressed proto‑oncogenes driving proliferation; Tumour suppressors (e.g., p53, Rb) normally inhibit cell cycle or promote apoptosis.
41) Name common carcinogens.
Radiations (UV, ionizing), chemicals (tobacco tar, aflatoxins), oncogenic viruses (HPV, HBV), chronic inflammation.
42) Cancer detection and therapies.
Screening (Pap smear, mammography), imaging/biopsy, tumour markers; treatments include surgery, radiotherapy, chemotherapy, targeted/immune therapies.
43) What is metastasis?
Spread of cancer cells from primary tumour to distant sites forming secondary tumours.
44) What is angiogenesis in cancer?
Formation of new blood vessels to supply tumours; target for anti‑angiogenic drugs.
45) List harmful effects of tobacco.
Increases risk of cancers (lung, oral), COPD, cardiovascular disease; causes addiction via nicotine.
46) Health risks of alcohol abuse.
Liver cirrhosis, pancreatitis, cardiovascular issues, dependence, impaired judgment and accidents.
47) What are antibiotics? Why should misuse be avoided?
Drugs that kill/inhibit bacteria; misuse promotes antimicrobial resistance (AMR).
48) Explain vaccination and immunization.
Vaccination: administration of vaccine; Immunization: process of developing immunity (active or passive).
49) List general preventive measures for infectious diseases.
Sanitation, safe water, personal hygiene, nutrition, vaccination, vector control, health education.
50) What is quarantine and isolation?
Quarantine: restrict movement of exposed but asymptomatic persons; Isolation: separate infected individuals to prevent spread.