Unit 3: Biology and Human Welfare

Chapter 1: Human Health and Diseases

Common Communicable Diseases

• Viral: Common Cold, Dengue, Chikungunya
• Bacterial: Typhoid, Pneumonia, Plague
• Protozoal: Amoebiasis, Malaria
• Helminthic: Ascariasis, Filariasis (Elephantiasis)
• Fungal: Ringworm

Malaria

• Cause: Plasmodium (a protozoan)
• Vector: Female Anopheles mosquito
• Symptoms: Recurring fever, chills, headache
• Life Cycle: Involves both human (liver, RBCs) and mosquito hosts.
• Prevention: Mosquito control is key.

Immunity

• Innate Immunity (Non-specific):
  • Present from birth.
  • Includes physical, physiological, cellular, and cytokine barriers.
• Acquired Immunity (Specific):
  • Develops after exposure to a pathogen.
  • Characterized by memory.

Types of Acquired Immunity

• Active Immunity: Body produces its own antibodies.
  • Natural: After infection.
  • Artificial: Through vaccination.
• Passive Immunity: Ready-made antibodies are received.
  • Natural: Mother to fetus/infant.
  • Artificial: Antivenom, antitoxins.

Humoral vs. Cell-Mediated Immunity

• Humoral Immunity (AMI):
  • Mediated by B-lymphocytes.
  • Involves production of antibodies.
• Cell-Mediated Immunity (CMI):
  • Mediated by T-lymphocytes.
  • Directly attacks infected cells.
  • Responsible for graft rejection.

AIDS (Acquired ImmunoDeficiency Syndrome)

• Cause: Human Immunodeficiency Virus (HIV), a retrovirus.
• Mechanism: HIV attacks and destroys helper T-cells, weakening the immune system.
• Transmission: Sexual contact, contaminated blood, shared needles, mother to child.
• Diagnosis: ELISA test.
• Prevention: Safe sex, screening blood, avoiding shared needles.

Cancer

• Uncontrolled cell growth and proliferation.
• Tumors:
  • Benign: Non-spreading.
  • Malignant: Cancerous, can spread (metastasis).
• Causes (Carcinogens): Radiation, chemicals (tobacco), viruses.
• Treatment: Surgery, radiotherapy, chemotherapy, immunotherapy.

Drug and Alcohol Abuse

• Commonly Abused Drugs:
  • Opioids: Heroin, Morphine
  • Cannabinoids: Marijuana, Hashish
  • Cocaine
• Effects: Addiction, organ damage (liver cirrhosis), mental and social problems.
• Prevention: Education, counseling, avoiding peer pressure.