Human Health and Diseases: Key Concepts and Questions

1. What is the first infective stage of the malarial parasite in man?

Answer: Sporozoite.

2. What is HIV?

Answer: HIV is a virus that causes AIDS by destroying the immune system.

3. Which bacteria causes typhoid?

Answer: Salmonella typhi.

4. What are the different types of barriers in innate immunity?

Answer: Innate immunity includes the following types of barriers:

• Physical barriers: Skin and mucous membranes prevent the entry of pathogens.
• Physiological barriers: Acid in the stomach, tears, and saliva destroy microbes.
• Cellular barriers: Phagocytic cells like neutrophils and macrophages.
• Cytokine barriers: Interferons released by virus-infected cells.

5. What are STDs? Name two examples and preventive measures.

Answer: STDs (Sexually Transmitted Diseases) are diseases transmitted through sexual contact.

Examples:

• AIDS
• Syphilis or Gonorrhoea

Preventive measures:

• Use of condoms during sexual intercourse.
• Avoid multiple sexual partners and maintain sexual hygiene.

6. What are the main causes of cancer?

Answer: The main causes of cancer are:

• Carcinogens: Chemical substances, tobacco, and smoking.
• Radiations: UV rays and X-rays cause DNA damage.
• Oncogenic viruses: Some viruses induce cancer.
• Genetic mutations: Changes in genes controlling cell division.

7. Difference between T-lymphocytes and B-lymphocytes

Answer:

• T-lymphocytes: Mature in the thymus, involved in cell-mediated immunity, and do not produce antibodies.
• B-lymphocytes: Mature in the bone marrow, involved in humoral immunity, and produce antibodies.

8. Difference between active and passive immunity

Answer:

• Active immunity: Produced by the body itself, long-lasting, and has memory cells.
• Passive immunity: Antibodies are received from outside, short-lived, and has no memory cells.

9. Symptoms of typhoid

Answer:

• Prolonged high fever
• Weakness and headache
• Abdominal pain and constipation/diarrhoea

10. Prevention of AIDS

Answer:

• Use of condoms during sexual intercourse.
• Avoid multiple sexual partners.
• Use sterilized needles and screened blood.

11. Causative organism and symptoms of amoebiasis

Answer:

• Causative organism: Entamoeba histolytica.
• Symptoms: Abdominal pain and diarrhoea with mucus and blood.

12. What is auto-immunity?

Answer: Auto-immunity is a condition in which the immune system attacks the body's own cells. Example: Rheumatoid arthritis or Systemic lupus erythematosus.

13. Three sexually transmitted diseases

Answer: 1. AIDS, 2. Syphilis, 3. Gonorrhoea.

14. Barriers in innate immunity

Answer:

• Physical barriers: Skin, mucous membranes.
• Physiological barriers: Stomach acid, tears, saliva.
• Cellular barriers: Neutrophils, macrophages.

15. Prevention of AIDS

Answer: Use of condoms, avoid multiple sexual partners, and use sterilized needles and screened blood.

16. ELISA full form and detected diseases

Answer: ELISA: Enzyme-Linked Immunosorbent Assay. Diseases: AIDS, Hepatitis-B.

17. Molecular structure of an antibody

Answer:

18. Acquired vs. innate immunity

Answer:

• Innate immunity: Inborn, non-specific defense present from birth (skin, mucous membranes, phagocytes).
• Acquired immunity: Develops after infection or vaccination; it is specific and has memory.

19. Allopathy vs. antibiosis

Answer:

• Allopathy: Treatment using drugs that produce effects opposite to disease symptoms.
• Antibiosis: Treatment using antibiotics that kill or inhibit disease-causing microbes.

20. Vaccination vs. immunisation

Answer:

• Vaccination: Administration of a vaccine (artificial process).
• Immunisation: Development of immunity as a result of vaccination or infection.

21. Sex-linked inheritance

Answer: Refers to the transmission of traits controlled by genes located on sex chromosomes. Example: Colour blindness or Haemophilia.

22. Four primary signs of cancer

Answer: Uncontrolled cell division, formation of tumours, loss of contact inhibition, and metastasis.

23. Characteristics of acquired immunity

Answer: Specificity to particular antigens, memory for faster secondary response, and involves B and T lymphocytes.

24. Drugs: Psychotropic and psychedelic

Answer: A drug is a chemical substance that alters body or mind functions.

• Psychotropic drugs: Affect mental activity (e.g., sedatives).
• Psychedelic drugs: Cause hallucinations (e.g., LSD).

25. Effects of drugs and alcohol

Answer: Addiction and dependence, damage to liver and brain, and impaired judgement and coordination.

26. Define drug and name one psychotropic drug

Answer: A drug is a substance that alters physiological or psychological functions. Example: Morphine or Diazepam.

27. Various types of cancer

Answer: Carcinoma, Sarcoma, Leukaemia, and Lymphoma.

28. Sexually transmitted disease

Answer: STDs are diseases transmitted through sexual contact. Example: AIDS, Syphilis, or Gonorrhoea.

29. Addiction vs. dependence

Answer:

• Addiction: Psychological craving for a substance.
• Dependence: Physical need of a substance to function normally.

30. Main causes of cancer

Answer: Cancer is caused by uncontrolled cell division due to mutations induced by carcinogens (tobacco, chemicals, radiation) and oncogenic viruses.

31. Effects of drug and alcohol abuse

Answer: Leads to addiction, damage to the nervous system, liver, heart, and kidneys, mental disorders, and social problems.

32. Life cycle of the malarial parasite

Answer: The infective stage for humans is the sporozoite. The cycle involves two hosts: humans (asexual cycle in liver and RBCs) and female Anopheles mosquitoes (sexual cycle in the gut).

33. Prevention and control of drug and alcohol abuse

Answer: Education and awareness, avoiding peer pressure, family support, professional counselling, and strict legal control.

34. Benign vs. malignant tumours

Answer:

• Benign: Non-cancerous, localized, slow growth, does not invade tissues.
• Malignant: Cancerous, spreads to other parts, rapid growth, invades nearby tissues, often fatal.

35. Immune systems of the body

Answer:

• Innate immunity: Non-specific, present at birth.
• Acquired immunity: Specific, develops after infection/vaccination (Humoral and Cell-mediated).

36. Species causing malaria and life cycle

Answer: Species: P. vivax, P. falciparum, P. malariae, P. ovale. The life cycle involves asexual multiplication in humans and sexual reproduction in mosquitoes.

37. Pneumonia: Acquisition, organisms, and symptoms

Answer: Acquired via inhalation of droplets. Organisms: Streptococcus pneumoniae, Haemophilus influenzae. Symptoms: Fever, chills, cough with sputum, chest pain, and difficulty breathing.

38. Cancer: Causes, detection, and diagnosis

Answer: Causes: Carcinogens, radiation, viruses, genetics. Detection: Biopsy, blood tests, CT scan, MRI.

39. STD, AIDS symptoms, and prevention

Answer: AIDS is caused by HIV. Symptoms: Fever, fatigue, weight loss, swollen lymph glands. Prevention: Safe sex, sterile needles, blood screening.

40. Harmful effects and prevention of drug addiction

Answer: Effects: Physical/mental damage, social issues. Prevention: Education, family support, counselling, and legal enforcement.