Health The Ultimate Treasure Class 8 Science Free Notes and Mind Map (Free PDF Download)

health

Health is much more than just not being sick – it includes feeling good physically, staying positive mentally, and having strong social relationships. In today’s world, we see changes in disease patterns where some diseases like smallpox have disappeared while others like diabetes are becoming more common.

Health: Is It More Than Not Falling Sick?

Looking at the health statistics around us, we can see that many Indians face various health challenges. About 11.4% of India’s population is diabetic, and over 100 million people in the country have diabetes according to ICMR reports. Air pollution has become a public health emergency and is one of the leading risk factors for health problems. Fast food consumption is contributing to rising diabetes rates, while 28.6% of Indians are now classified as obese.

The World Health Organization defines health as a ‘state of complete physical, mental, and social well-being, and not merely the absence of disease’. This definition shows us that being healthy involves three imp aspects working together harmoniously.

Three Aspects of Health

Physical Health

  • The body functions properly without disease or illness
  • All organs and organ systems work efficiently
  • Person has energy to perform daily activities
  • Body can recover from injuries and minor illnesses quickly

Mental Health

  • Person maintains a positive mindset and emotional balance
  • Can cope with stress and life challenges effectively
  • Has good concentration and mental clarity
  • Experiences appropriate emotions for different situations

Social Health

  • Enjoys good relationships with family and friends
  • Can adjust well with peer groups and society members
  • Participates actively in community activities
  • Feels connected and supported by others around them

A truly healthy person can perform various tasks more efficiently and cope well in different and difficult situations. They can adapt to changes and handle challenges that life brings their way.

Ayurvedic Understanding of Health

Ancient Indian wisdom through Ayurveda teaches us that true health comes from maintaining balance between body, mind, and surroundings. This holistic approach recognizes that health cannot be achieved by focusing on just one aspect while ignoring others.

Traditional Practices for Health

  • Following dinacharya (daily routine) helps maintain body rhythms
  • Practicing ritucharya (seasonal routine) keeps us aligned with natural changes
  • Eating fresh, wholesome food suited to one’s prakriti (body constitution)
  • Regular exercise and physical activity for strength and flexibility
  • Maintaining cleanliness in body and surroundings
  • Getting restful sleep to allow body and mind recovery
  • Keeping a calm mind through practices like yoga, meditation, and mindfulness

How Can We Stay Healthy?

Staying healthy requires conscious efforts in multiple areas of our daily life. It involves eating nutritious food, maintaining hygiene, staying in clean environments, exercising regularly, getting proper sleep, spending time with loved ones, and having a positive attitude toward life.

Good Habits for Health

Personal Care Habits

  • Keep yourself clean and maintain personal hygiene daily
  • Brush teeth twice daily and wash hands frequently
  • Take regular baths and keep clothes clean
  • Cut nails regularly and maintain hair cleanliness

Physical Activity Habits

  • Stay physically active through various forms of movement
  • Exercise regularly according to your age and capacity
  • Play outdoor games and sports when possible
  • Walk or cycle instead of always using vehicles

Nutritional Habits

  • Eat a healthy and balanced diet with variety
  • Include plenty of fruits and vegetables in meals
  • Choose whole grains over processed foods
  • Drink adequate water throughout the day

Mental Health Habits

  • Make time to relax or meditate every day
  • Spend quality time with family and friends
  • Engage in hobbies and activities you enjoy
  • Practice deep breathing or pranayama regularly

Habits to Avoid

Technology-Related Problems

  • Spending too much time on mobile phones or digital screens
  • Excessive screen watching that leads to dry eye disease in children
  • Social media immersion that increases loneliness
  • Missing real-world interactions due to virtual engagement

Poor Eating Habits

  • Eating fast food and junk food frequently
  • Skipping meals, especially breakfast
  • Consuming excessive oil, sugar, and processed foods
  • Not drinking enough water throughout the day

Lifestyle Problems

  • Sleeping very late or not getting enough sleep
  • Leading sedentary lifestyle without physical activity
  • Not managing stress effectively
  • Ignoring symptoms of illness until they become serious

Maintain a Healthy Lifestyle

Dietary Guidelines

  • Eat a balanced diet with plenty of fruits, vegetables, and whole grains
  • Avoid processed, fatty, or sugary foods and drinks
  • Reduce oil and sugar content in diet by at least 10%
  • Choose fresh, locally available seasonal foods when possible

Physical Activity Recommendations

  • Stay physically active by playing outdoors regularly
  • Include walking, running, cycling, or structured exercise in routine
  • Participate in sports and recreational activities
  • Limit sedentary activities and take movement breaks

Mental Wellness Practices

  • Get enough sleep to help body and mind rest and recover properly
  • Practice yoga or simple breathing exercises regularly
  • Manage stress through relaxation techniques and hobbies
  • Maintain positive social relationships and emotional connections

Avoidance of Harmful Substances

  • Say ‘NO’ to tobacco in all forms including smoking and chewing
  • Avoid alcohol consumption, especially for young people
  • Stay away from addictive drugs and substances
  • Be cautious about medications and take them only as prescribed

Keep the Environment Clean

The environment around us directly affects our health and well-being. Clean surroundings support good health while polluted environments can cause various diseases and health problems.

Environmental Impact on Health

Clean environments with fresh air, pure water, and proper sanitation help us stay healthy and feel better. In contrast, polluted areas with contaminated air and water can cause immediate health problems like breathing difficulties and long-term issues like asthma.

Air Quality Concerns

  • In cities, air pollution from vehicles and factories causes coughing and asthma
  • The Air Quality Index (AQI) helps us understand how clean the air is
  • Air pollution is now recognized as a public health emergency
  • Poor air quality affects children and elderly people more severely

Water and Sanitation

  • Safe drinking water reduces cases of water-borne and vector-borne diseases
  • Proper waste management prevents breeding of disease-carrying vectors
  • Clean toilets and sewage systems prevent contamination of water sources
  • Regular handwashing can reduce infections by up to 50%

Climate and Health Connection

Seasonal Disease Patterns

  • Arrival of monsoon leads to increase in malaria and dengue cases
  • Stagnant water provides breeding grounds for mosquitoes
  • Humidity and temperature changes affect disease transmission
  • Climate change may lead to emergence of new types of diseases

Environmental Factors

  • Clean playgrounds and recreational areas support physical activity
  • Polluted areas with flies and mosquitoes increase disease risk
  • Green spaces and trees improve air quality and mental health
  • Proper drainage systems prevent waterlogging and vector breeding

How Do We Know That We Are Unwell?

Our body usually works in predictable ways to maintain health and normal functioning. When something is not working properly inside our body, we experience various indicators that tell us we might be unwell.

Symptoms vs Signs

Symptoms

  • What we personally feel inside our body
  • Examples include pain, tiredness, dizziness, nausea
  • Cannot be directly observed by others
  • Personal experiences that only the patient can describe

Signs

  • What can be seen, measured, or detected by others
  • Examples include fever, rash, swelling, high blood pressure
  • Can be observed and measured by healthcare providers
  • Objective indicators that doctors use for diagnosis

Common Indicators of Illness

Physical Indicators

  • Changes in body temperature (fever or feeling cold)
  • Unusual pain or discomfort in body parts
  • Changes in skin color, texture, or appearance of rashes
  • Swelling in different parts of the body

Functional Changes

  • Difficulty in performing usual daily activities
  • Changes in appetite or eating patterns
  • Sleep disturbances or unusual tiredness
  • Changes in breathing patterns or heart rate

Behavioral Changes

  • Mood changes or emotional disturbances
  • Difficulty concentrating on tasks
  • Social withdrawal or isolation
  • Loss of interest in usual activities

These symptoms and signs help doctors understand what might be causing illness and determine appropriate treatment approaches.

Diseases: What Are the Causes and Types?

A disease is a condition that affects the normal working of the body or mind. It occurs when one or more organs or organ systems stop functioning properly, leading to various health problems.

Major Categories of Diseases

Diseases can be grouped into two major types based on their causes and how they spread from person to person.

Communicable Diseases

  • Caused by pathogens like bacteria, viruses, fungi, worms, or protozoa
  • Can spread from one person to another through various routes
  • Examples include typhoid, dengue, flu, chickenpox, COVID-19
  • Require specific prevention and treatment strategies

Non-communicable Diseases (NCDs)

  • Not caused by infectious pathogens
  • Cannot spread from person to person
  • Usually linked to lifestyle, diet, genetics, and environmental factors
  • Examples include diabetes, heart disease, cancer, asthma

Rising Trend of Non-Communicable Diseases

In recent years, non-communicable diseases have become more common in India due to changing lifestyles and living conditions.

Reasons for Increase

  • People are eating more processed and fast food
  • Physical activity levels have decreased significantly
  • Life expectancy has increased, leading to age-related diseases
  • Stress levels have increased due to modern lifestyle pressures
  • Environmental pollution has worsened in many areas

Current Impact

  • Most deaths in India are now caused by NCDs
  • Diabetes affects over 100 million Indians
  • Heart disease and cancer rates are rising
  • Obesity has become a significant health concern

How are Communicable Diseases Caused and Spread?

All communicable diseases are caused by pathogens that can enter our body through various routes and then spread to other people.

Common Transmission Routes

MethodDescriptionExamples
AirborneThrough droplets when infected person coughs or sneezesCold, flu, tuberculosis
Direct contactThrough touching infected person or their belongingsSkin infections, some eye infections
Contaminated food/waterThrough eating or drinking contaminated substancesTyphoid, cholera, hepatitis A
Vector-borneThrough insects like mosquitoes and fliesMalaria, dengue, chikungunya
Animal bitesThrough bites from infected animalsRabies

Vector-Borne Diseases

  • Some pathogens are spread by insects called vectors
  • Mosquitoes spread malaria, dengue, and chikungunya
  • Houseflies can carry bacteria that cause food poisoning
  • Controlling vector populations helps prevent these diseases

How Does Our Body Protect Us Against Diseases?

Our body has a natural defense system called the immune system that works continuously to protect us from harmful pathogens and foreign substances.

Components of Immune System

Physical Barriers

  • Skin acts as first line of defense against pathogens
  • Mucus in nose and throat traps harmful particles
  • Stomach acid kills many bacteria that enter through food
  • Tears and saliva contain substances that fight infections

White Blood Cells

  • Special cells that patrol the body looking for harmful invaders
  • Different types of white blood cells have specific functions
  • Some cells eat and destroy pathogens directly
  • Others produce antibodies that neutralize harmful substances

Memory Function

  • Immune system remembers pathogens it has encountered before
  • Second exposure to same pathogen triggers faster, stronger response
  • This memory function is the basis for how vaccines work
  • Natural immunity develops after recovering from certain diseases

How Vaccines Work

Vaccines are biological preparations that help our immune system learn to fight specific diseases without causing the actual illness.

Vaccine Composition

  • Dead or weakened pathogens that cannot cause disease
  • Harmless parts of pathogens like proteins or sugars
  • Sometimes harmless substances that look similar to real pathogens
  • Additional ingredients that help immune system respond better

Immunization Process

  • Vaccine introduces harmless version of pathogen to immune system
  • White blood cells learn to recognize and fight this pathogen
  • Immune system creates memory cells that remember the pathogen
  • If real pathogen enters body later, memory cells trigger immediate response

Historical Example: Smallpox Vaccine

  • Edward Jenner discovered first vaccine in late 1700s
  • Noticed that people who had cowpox did not get smallpox
  • Used material from cowpox blisters to protect against smallpox
  • Mass vaccination campaigns eventually eradicated smallpox worldwide

Traditional Indian Vaccination Practices

Long before modern vaccines, India had traditional methods for disease prevention.

Variolation Practice

  • Used material from smallpox sores to create mild infection
  • This built immunity against more serious smallpox disease
  • People who performed this practice were called teekedaars
  • Shows that principles of immunization were understood in ancient times

Treatment of Diseases

When our immune system cannot protect us effectively against infectious diseases, we need medical treatment to recover our health.

Antibiotic Treatment

How Antibiotics Work

  • Medicines that kill bacteria causing infectious diseases
  • Target specific parts of bacterial cells that differ from human cells
  • Work only against bacterial infections, not viral diseases
  • Do not affect diseases caused by protozoa, fungi, or other pathogens

Discovery of Penicillin

  • First antibiotic discovered by Alexander Fleming in 1928
  • Noticed that mould on petri dish stopped bacteria growth
  • Realized mould released substance that killed bacteria
  • This accidental discovery revolutionized treatment of bacterial infections

Problem of Antibiotic Resistance

Overuse and misuse of antibiotics has led to development of resistant bacteria that can survive antibiotic treatment.

How Resistance Develops

  • Some bacteria naturally survive antibiotic treatment
  • These resistant bacteria multiply when other bacteria are killed
  • Resistant bacteria can transfer resistance genes to other bacteria
  • Overuse of antibiotics speeds up this natural selection process

Consequences of Resistance

  • Common infections become harder to treat
  • Patients need stronger, more expensive antibiotics
  • Treatment takes longer and may be less effective
  • Risk of serious complications and death increases

Prevention of Resistance

  • Use antibiotics only when prescribed by qualified doctors
  • Take complete course of antibiotics as directed
  • Never share antibiotics with others or save leftover pills
  • Do not pressure doctors to prescribe antibiotics for viral infections

Traditional Medicine Systems

Ayurveda, Siddha, and Unani

  • Used in India for many years to manage health problems
  • Use natural substances like herbs, oils, and minerals
  • Focus on healthy lifestyle and balanced diet for prevention
  • Can help with some conditions and everyday wellness

Limitations

  • May not be effective for all diseases and conditions
  • Cannot replace modern medicine for serious infections
  • Should be used alongside, not instead of, conventional treatment
  • Require proper training and knowledge for safe use

Treatment of Non-Communicable Diseases

Management Approach

  • Focus on managing symptoms and improving quality of life
  • Use medications to control disease progression
  • Lifestyle changes including diet and exercise modifications
  • Rehabilitation services to maintain function and independence

Importance of Early Diagnosis

  • Early detection allows for better treatment outcomes
  • Continuous care helps prevent disease complications
  • Regular monitoring helps adjust treatment as needed
  • Patient education improves self-management skills

Questions and Answers

How does your body respond to an infection such as common cold?

  • When cold virus enters the body, immune system immediately starts working to fight the infection by sending white blood cells to attack the virus and prevent its spread throughout the body
  • The body produces more mucus in nose and throat to trap virus particles and wash them out, which causes runny nose and sneezing symptoms
  • Body temperature may rise slightly (fever) to create unfavorable conditions for virus multiplication and help immune cells work more effectively
  • Inflammatory response causes swelling in nasal passages and throat, leading to congestion and sore throat that we experience during cold
  • Immune system produces specific antibodies against the cold virus, which help neutralize the virus and clear it from the body
  • Recovery usually takes 7-10 days as immune system successfully eliminates the virus and body returns to normal functioning

We rarely see cases of smallpox or polio these days, but diseases like diabetes and heart problems are more common. Why?

  • Smallpox and polio have been largely eliminated through successful vaccination programs that created widespread immunity in the population over many decades
  • These diseases were caused by specific viruses that could be prevented effectively through vaccines, and international cooperation helped achieve global eradication
  • Diabetes and heart problems are non-communicable diseases that cannot be prevented by vaccines since they are not caused by infectious agents
  • Modern lifestyle changes including increased consumption of processed foods, reduced physical activity, and higher stress levels contribute to rising diabetes and heart disease
  • Urbanization has led to more sedentary jobs and reduced opportunities for physical activity, increasing risk factors for these diseases
  • Improved healthcare has increased life expectancy, meaning more people live long enough to develop age-related conditions like diabetes and heart disease
  • Environmental factors like air pollution and chemical exposure may also contribute to increased rates of non-communicable diseases in modern society

Could climate change lead to new types of diseases?

  • Climate change can expand the geographic range of disease-carrying vectors like mosquitoes and ticks, bringing vector-borne diseases to new areas where people lack immunity
  • Rising temperatures and changing precipitation patterns create new breeding grounds for disease vectors and extend their active seasons throughout the year
  • Extreme weather events like floods and droughts can disrupt.

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