Human Health and Disease – Class 12 Biology Notes | Complete NCERT Summary
🧬 Chapter 8: Human Health and Disease – Class 12 Biology --- 🔹 What is Health? A state of complete physical, mental and social well-being. WHO defines health as not just absence of disease. Factors affecting health: Nutrition, environment, lifestyle, social conditions. --- 🔹 Common Diseases: A. Infectious Diseases: Caused by pathogens (bacteria, virus, fungi, protozoa, helminths). Examples: Disease Causative Organism Transmission Typhoid Salmonella typhi Contaminated food/water Pneumonia Streptococcus pneumoniae Air (droplets) Common Cold Rhinovirus Direct contact Malaria Plasmodium (protozoa) Female Anopheles mosquito Ascariasis Ascaris (worm) Contaminated food/water Filariasis Wuchereria bancrofti Mosquito bite 📌 Important Diagram: Plasmodium life cycle in humans and mosquito --- B. Non-Infectious Diseases: Caused by genetic, lifestyle or environmental factors. Examples: Cancer, Diabetes, Hypertension 📌 Diagram: Difference between benign and malignant tumor cells --- 🔹 Imm...