Unit VII – Human Health & Disease (Question Bank)

📘 UNIT VII – Human Health & Disease

🔹 2 MARKS QUESTIONS

Q1. What is the causative organism of malaria? Name its vector.
Malaria is caused by Plasmodium species (P. vivax, P. falciparum, P. malariae).
Transmitted by female Anopheles mosquito.
Q2. Define allergy and name two allergens.
Allergy is an exaggerated response of the immune system to allergens.
Examples: pollen grains, dust mites.
Q3. Name two autoimmune diseases.
Rheumatoid arthritis, Myasthenia gravis.
Q4. What is active immunity?
Active immunity is protection developed in the host by production of antibodies after infection or vaccination.

🔹 5 MARKS QUESTIONS

Q5. Write short notes on innate immunity.
Innate immunity = natural, non-specific defence present from birth.
Components:
  • Physical – skin, mucous membrane
  • Physiological – stomach acid, saliva, tears
  • Cellular – phagocytes (neutrophils, macrophages, NK cells)
  • Cytokines – interferons vs. viral infections
Significance: First line defence before adaptive immunity.
Q6. Explain the life cycle of Plasmodium in humans.
- Infected female Anopheles bite injects sporozoites.
- Sporozoites → liver (schizogony) → merozoites.
- Merozoites infect RBCs → multiply → rupture → fever cycle.
- Some form gametocytes → mosquito picks them up.
- Symptoms: chills, fever, anemia.
Sporozoite
Liver stage
RBC stage
Fever cycles
Gametocytes
Q7. Distinguish between active and passive immunity.
Active Immunity Passive Immunity
Produced by host after exposure to antigen Ready-made antibodies given
Example: Vaccination (Polio, Measles) Example: Anti-venom serum, maternal antibodies

🔹 12 MARKS QUESTIONS

Q8. Describe the types of immunity and explain humoral and cell-mediated immunity.
Immunity = ability to resist infection.

1. Innate Immunity – Non-specific, at birth.
2. Acquired Immunity – Specific, has memory.
  • Humoral Immunity: B-cells → plasma cells → antibodies. Neutralize toxins, opsonization, complement activation.
  • Cell-Mediated Immunity (CMI): T-cells. Helper T → activate B & Tc. Cytotoxic T → kill virus-infected/cancer cells.
Significance:
  • Humoral → extracellular microbes
  • CMI → intracellular pathogens, cancer defence
Q9. Explain AIDS in detail.
Causative agent: HIV (retrovirus).
Transmission: sexual contact, blood transfusion, needles, mother-to-child.
Pathogenesis: HIV infects CD4+ T-cells, destroys immunity → opportunistic infections.
Symptoms: weight loss, prolonged fever, diarrhea, fungal/TB infections.
Treatment: No cure, ART/HAART used.
Prevention: safe sex, screened blood, disposable syringes.
Q10. Explain the life cycle of malarial parasite and its control measures.
Same as Q6 (life cycle) + Control:
  • Mosquito nets, repellents
  • Spraying insecticides
  • Prevent water stagnation
  • Prophylactic drugs (chloroquine)