🌸Chapter 7
Human Health and Diseases
(3 Marks)
1. Define health and explain its significance.
Answer:
Health is a state of complete physical, mental, and social well-being.
Significance:
1.
Healthy
individuals contribute productively to society.
2.
It
allows better resistance against diseases.
3.
Promotes
a balanced and happy life.
2. Differentiate between infectious
and non-infectious diseases with examples.
Answer:
|
Type |
Infectious |
Non-Infectious |
|
Cause |
Pathogens |
Genetic, lifestyle, or environmental factors |
|
Spread |
Transmitted |
Not transmitted |
|
Example |
Tuberculosis, Malaria |
Cancer, Diabetes |
3. Name the causative organism, mode
of transmission, and preventive measure for typhoid.
Answer:
- Causative organism: Salmonella typhi
- Transmission: Contaminated food and water
(faeco-oral route)
- Prevention: Proper sanitation,
vaccination, and hygiene.
4. Explain how pneumonia spreads and
mention two symptoms.
Answer:
- Spread: By inhaling droplets released
during coughing/sneezing from an infected person.
- Symptoms:
1.
Difficulty
in breathing and chest pain
2.
Fever
and cough with mucus
5. Write the life cycle of Plasmodium
in humans briefly.
Answer:
1.
Plasmodium enters human blood as sporozoites
via female Anopheles.
2.
Sporozoites
infect liver cells, multiply as merozoites.
3.
Merozoites
infect RBCs → burst → cause fever.
4.
Some
become gametocytes, which infect mosquitoes again.
6. What are the symptoms of malaria?
How can it be prevented?
Answer:
Symptoms:
- High fever with chills and
sweating
- Shivering and weakness
Prevention: - Avoid mosquito bites
- Use mosquito nets and
repellents
- Eliminate stagnant water
(mosquito breeding sites)
7. Describe the disease amoebiasis
(amoebic dysentery).
Answer:
- Causative agent: Entamoeba histolytica
- Symptoms: Abdominal pain, dysentery with
mucus and blood, nausea
- Transmission: Contaminated food and water
8. Write the causes and symptoms of
ascariasis.
Answer:
- Cause: Ascaris lumbricoides
(intestinal roundworm)
- Symptoms:
1.
Abdominal
pain
2.
Intestinal
blockage
3.
Malnutrition
- Transmission: Ingestion of eggs from
contaminated food/water.
9. Write short notes on filariasis
(elephantiasis).
Answer:
- Causative agent: Wuchereria bancrofti / W.
malayi
- Vector: Culex mosquito
- Symptoms: Chronic inflammation and
swelling of limbs and scrotum.
- Control: Mosquito control and early
diagnosis.
10. Write the causes, symptoms, and
prevention of ringworm.
Answer:
- Cause: Fungi — Microsporum, Trichophyton,
Epidermophyton
- Symptoms: Itchy circular lesions on
skin/scalp
- Prevention: Personal hygiene, avoid
sharing clothes/towels
11. Name four sexually transmitted
diseases (STDs) and their causative organisms.
Answer:
1.
AIDS – HIV
2.
Syphilis – Treponema pallidum
3.
Gonorrhea – Neisseria gonorrhoeae
4.
Genital
herpes – Herpes
simplex virus
12. How does HIV infect the human
body?
Answer:
1.
HIV
binds to CD4 receptors on helper T-cells.
2.
Inserts
viral RNA → converts to DNA using reverse transcriptase.
3.
Viral
DNA integrates into host genome → multiplies → destroys T-cells → weakens
immunity.
13. Mention four main modes of
transmission of HIV.
Answer:
1.
Unprotected
sexual contact with an infected person
2.
Transfusion
of infected blood
3.
Use
of infected needles/syringes
4.
From
infected mother to child during pregnancy or breastfeeding
14. Write two symptoms each of early
and late stages of AIDS.
Answer:
- Early: Fever, weight loss, fatigue
- Late: Persistent diarrhea, frequent
infections, reduced immunity
15. What is immunity? Mention its
types.
Answer:
Immunity is the ability of the body to resist disease.
Types:
1.
Innate
immunity (nonspecific)
2.
Acquired
immunity (specific)
16. Explain the four types of innate
immunity barriers.
Answer:
1.
Physical
barriers: Skin,
mucous membranes
2.
Physiological
barriers: HCl in
stomach, saliva
3.
Cellular
barriers:
Phagocytes (WBCs)
4.
Cytokine
barriers:
Interferons
17. Differentiate between innate and
acquired immunity.
Answer:
|
Basis |
Innate |
Acquired |
|
Nature |
Inborn, nonspecific |
Developed, specific |
|
Memory |
Absent |
Present |
|
Example |
Skin, macrophages |
Antibodies after infection/vaccination |
18. What is active and passive
immunity? Give examples.
Answer:
- Active: Developed after
infection/vaccination (e.g., polio vaccine).
- Passive: Ready-made antibodies given
(e.g., anti-tetanus serum).
19. What are vaccines? How do they
work?
Answer:
Vaccines contain weakened or dead pathogens.
They stimulate immune response → produce memory cells → provide long-term
protection.
20. Give examples of any three
vaccines and the diseases they prevent.
Answer:
1.
BCG
– Tuberculosis
2.
DPT
– Diphtheria, Pertussis, Tetanus
3.
Hepatitis
B vaccine – Hepatitis B
21. What are allergens? How does
allergy occur?
Answer:
- Allergens: Substances like pollen, dust,
food that cause hypersensitivity.
- Mechanism: Allergen triggers IgE antibody
release → histamine from mast cells → inflammation and itching.
22. Define autoimmunity and give two
examples.
Answer:
Autoimmunity is when the immune system attacks self-cells.
Examples:
1.
Rheumatoid
arthritis
2.
Myasthenia
gravis
23. What is cancer? Mention its main
characteristics.
Answer:
Cancer is uncontrolled cell division.
Characteristics:
1.
Loss
of growth control
2.
Formation
of tumor
3.
Metastasis
(spreading to other parts)
24. Differentiate between benign and
malignant tumors.
Answer:
|
Feature |
Benign |
Malignant |
|
Growth |
Slow |
Rapid |
|
Spread |
Localized |
Metastasizes |
|
Danger |
Less harmful |
Life-threatening |
25. What are carcinogens? Give two
examples.
Answer:
Carcinogens are substances that cause cancer.
Examples:
1.
Tobacco
smoke (chemical carcinogen)
2.
UV
radiation
26. Name any two oncogenic viruses
and the cancers they cause.
Answer:
1.
Human
Papilloma Virus (HPV)
– Cervical cancer
2.
Epstein-Barr
Virus (EBV)
– Burkitt’s lymphoma
27. Write the principle of cancer
treatment.
Answer:
1.
Surgery: Remove tumor
2.
Radiation
therapy: Destroy
cancer cells by radiation
3.
Chemotherapy: Use anticancer drugs to kill
rapidly dividing cells
28. What are interferons? Mention
their role.
Answer:
Interferons are antiviral proteins secreted by infected cells.
They inhibit viral replication and enhance immune defense.
29. What is drug abuse?
Answer:
The habitual and excessive use of drugs for non-medical purposes leading to
physical and mental dependence.
30. What is addiction? Give an
example.
Answer:
Addiction is psychological and physical dependence on a substance.
Example: Alcohol or heroin addiction.
31. Mention three commonly abused
drugs and their sources.
Answer:
1.
Heroin
– Opium poppy (Papaver somniferum)
2.
Cocaine
– Erythroxylum coca
3.
Marijuana
– Cannabis sativa
32. Write three harmful effects of
alcohol abuse.
Answer:
1.
Liver
damage (cirrhosis)
2.
Reduced
concentration and judgment
3.
Depression
and behavioral changes
33. Mention the mode of action of
cocaine.
Answer:
Cocaine acts as a stimulant of the central nervous system by increasing
dopamine levels, causing euphoria and energy.
34. What is heroin? Write its
effects.
Answer:
- Chemical name: Diacetylmorphine
- Effect: Acts as a depressant and slows
body functions; causes euphoria and addiction.
35. Differentiate between stimulants
and depressants with examples.
Answer:
|
Type |
Effect |
Example |
|
Stimulant |
Increase alertness and activity |
Cocaine, Caffeine |
|
Depressant |
Reduce body function |
Alcohol, Morphine |
36. What are hallucinogens? Give two
examples.
Answer:
Drugs that alter perception and cause hallucinations.
Examples: LSD, Marijuana
37. What are opioids? Give examples.
Answer:
Opioids are depressant drugs derived from opium.
Examples: Morphine, Heroin, Codeine
38. What are cannabinoids? Name
their source.
Answer:
Psychoactive compounds that affect brain function.
Source: Cannabis sativa (marijuana, hashish, ganja)
39. What are withdrawal symptoms?
Answer:
Unpleasant symptoms when a drug-dependent person stops using it.
Examples: Anxiety, sweating, vomiting, depression
40. What are the preventive measures
for drug and alcohol abuse?
Answer:
1.
Education
and awareness
2.
Parental
guidance
3.
Peer
support and healthy lifestyle
41. Mention two national-level
agencies working against drug abuse.
Answer:
1.
NDDTC
(AIIMS) – National Drug Dependence Treatment Centre
2.
Narcotics
Control Bureau (NCB)
42. Explain the importance of
counseling in preventing drug abuse.
Answer:
Counseling helps individuals understand the harmful effects, build
self-control, and overcome peer pressure.
43. How does the immune system
respond to infection?
Answer:
1.
Pathogen
entry → recognized as foreign
2.
Activation
of B and T lymphocytes
3.
Production
of antibodies → destruction of pathogen
44. What are antigens and
antibodies?
Answer:
- Antigen: Foreign substance that
triggers immune response.
- Antibody: Protein produced by B-cells
that neutralizes antigens.
45. Explain the role of memory cells
in immunity.
Answer:
Memory cells “remember” previous infections and respond faster and stronger
upon reinfection.
46. Why does a person suffer only
once from chickenpox?
Answer:
Because memory cells formed during the first infection provide lifelong
immunity.
47. Write the causes, symptoms, and
prevention of common cold.
Answer:
- Cause: Rhino viruses
- Symptoms: Nasal congestion, sore throat,
cough
- Prevention: Avoid contact with infected
persons; maintain hygiene
48. How do vaccines protect
individuals and the community?
Answer:
1.
Stimulate
immunity in vaccinated individuals
2.
Reduce
spread by herd immunity
3.
Help
eradicate diseases (e.g., smallpox)
49. How can the immune system become
a threat to the body itself?
Answer:
When it attacks self-cells (autoimmunity) → diseases like rheumatoid arthritis
or Type I diabetes.
50. Describe three ways to maintain
good health.
Answer:
1.
Balanced
diet and regular exercise
2.
Proper
hygiene and vaccination
3.
Stress
management and avoiding addictions
