Human Health and Disease

Human health and disease is a basic focus on the physical mental and social well-being of individuals as well as the study of disease and their causes. It helps in preventing the symptoms and also suggests treatments. It examines the mechanisms like the immune system which explores disorders, infections and lifestyles related to diseases. Human health and disease is one of the most important topics in biology. The chapter carries a weightage of 5-6% of the total marks in NEET and 3-4% of the weightage of other entrance exams like Paramedical and Nursing.

Important Topics of Human Health and Diseases

• Factors affecting Health
• Types of Diseases
• Immunity
• Alcohol and Drug Abuse
• Important Concepts - Pathogens, Vaccination, Cancer, AIDS

Overview of the Chapter

The "Human Health and Disease" chapter of Class 12 CBSE deals with the concept of health, its importance, and the numerous factors affecting it. The chapter further provides a series of causes of disease and various diseases, including infectious and non-infectious diseases, along with prevention and control. It further explains the immune system with accounts for innate and acquired immunity as well as vaccines. It covers such common human diseases as malaria, cancer, and AIDS, among others, and lifestyle diseases. At the same time, it focuses on good health through balanced nutrition, hygiene, and exercise.

What is Health?

The term health is used very frequently but is much more extensive than the lack of illness or even fitness. Health was once thought to be a balance of certain "humours" in the body and mind. Today health is considered as an all-around state of complete physical, mental, and social well-being.

According to the World Health Organization, "health is a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity."

Practice Questions:

Health and Disease MCQ

Factors Affecting Health

Many factors affect our health:

• Genetic disorders inherited by parents cause deficiency or defects at birth.
• Infections are conditions brought about by microbes, such as bacteria or viruses.
• Lifestyle, diet, exercise, sleep, and habits all contribute to fitness or overall good health.

Factors Affecting Physical Health

• Nutrition: Adequate nutrition fuels body operations.
• Physical Activity: Exercise keeps your heart healthy, strengthens, and remains flexible.
• Sleep: This is needed to restore and promote emotional health.
• Hygiene: Keeps diseases and infections away.

Factors Affecting Mental Health

• Stress: Chronic stress can lead to anxiety and depression
• Lifestyle: Diet, exercise, and substance abuse can lead to devastating effects on mental health
• Trauma: Previous trauma or abuse leads to mental disorders
• Genetics: Histories of mental illnesses in the family predispose an individual to mental disorders
• Environment: Lifestyle and chronic illness can affect an individual's mental well-being
• Brain Chemistry: Mental disorders can result from either balances or imbalances of neurotransmitters.
• Cognitive Health: Mental activity can contribute to maintaining healthy cognition.

What is Disease?

Due to interruptions in normal functions, when one or more organs are adversely affected, we say we are not healthy, which means we have a disease. Diseases are characterised by their signs and symptoms.

Microbes break the natural barrier to enter the body and interrupt normal functioning, causing diseases

Types of Diseases

Human diseases fall into two categories:

Congenital: A condition that has existed since birth

Acquired: Disease that occurs during a person's lifetime

Basic points about Congenital and Acquired are discussed below:

Causes of Diseases

Pathogens are often responsible for the disease. Lifestyle choices, genetic factors and environmental factors are other causes.

• Pathogens: Bacteria, viruses, parasites and fungi cause infectious diseases. For example, flu virus and tuberculosis.

• Lifestyle Choices: smoking, poor diet, and lack of exercise and sleep can result in heart disease, diabetes, and obesity.

• Genetic Factors: Genetic mutations are inherited and can lead to diseases such as cystic fibrosis or sickle cell anaemia.

• Environmental Factors: Pollution, exposure to hazardous chemicals, and poor living conditions can lead to respiratory diseases, cancers, and other health issues.

Transmission of Diseases

• Direct Contact: Diseases can be transmitted through Direct Contact. (For example, flu and chickenpox)

• Indirect Contact: Diseases are transmitted via contaminated surfaces, objects, or food and water (norovirus or hepatitis A).

• Vectors: Insects or animals act as a medium of transmission for diseases. They carry pathogens from one host to another. For example, mosquitoes transmit dengue and malaria fever.

• Transmission via Air: Pathogens present in droplets spread through the air. For example, tuberculosis and COVID-19.

Prevention of Diseases

There is a famous saying, “Prevention is better than cure." There is a lot to do to protect yourself from disease.

• Healthy Lifestyle: Have a balanced diet, sufficient sleep, and do some physical activities regularly to boost your immune system.

• Hygiene: There is some minute work to do to reduce the risk of infections. Maintain cleanliness and proper sanitation. Wash your hands regularly before having a meal.

• Vaccination: Immunise yourself against diseases like polio, influenza and measles by taking a vaccine and building immunity.

• Eliminate risk factors: avoid exposure to harmful substances such as smoking, and alcohol.

• Masks: Use masks to avoid pollution and air-borne diseases.

To treat bacterial, viral, and fungal infections, antibiotics, antivirals, and antifungals are used, respectively. Anti-inflammatory medications and painkillers are used to treat symptoms.

Common Human Diseases

The table below lists the common diseases that affect humans:

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Immunity

The immune system refers to the body's ability to fight off infections by invading viruses or foreign bodies. There are two types, such as.

Innate Immunity

This protection is available from the time of birth and provides barriers to attack by any foreign agent that causes infections. In addition, there are four types:

• Physical barrier

• Physiological barrier

• Cellular barrier

• Cytokine barrier

Acquired immunity

This type of resistance is directly related to the pathogen, and a person acquires it during his or her lifetime.

NCERT Solutions Subject-wise link:

• NCERT solutions for class 12 Physics

• NCERT solutions for class 12 Chemistry

• NCERT solutions for class 12 Mathematics

• NCERT solutions for class 12 Biology

Allergies

Allergies occur when the immune system reacts to certain things such as pollen, medicines, food, etc. The human immune system can distinguish between foreign molecules and bodies. However, there are cases when the body beats its cells. As a result, it is harmful to the body and is called an autoimmune disease. A usual example of such a given effect is rheumatoid arthritis.

NCERT Notes Subject Wise Link:

• NCERT notes Class 12 Maths

• NCERT notes Class 12 Physics

• NCERT notes Class 12 Chemistry

• NCERT notes Class 12 Biology

Cancer

Cancer refers to the uncontrolled and abnormal replication of cells. These cells capture and kill neighbouring tissues, and the continuous proliferation of cancer cells causes metastasis. The basics of cancer are discussed below:

Alcohol and Drug Abuse

Drug abuse commonly includes cannabinoids, coca alkaloids and opioids. Few medicines can be found in the fungus, especially in flowering plants. Opioid drugs also bind to the opioid receptors present in the human GI tract and the CNS (Central Nervous System).On the other hand, cannabinoids interact with cannabinoid receptors in the brain. Examples of such drugs are hashish, marijuana, and charm.

Types of Questions and Weightage of Human Health and Disease

During the preparation of the exam, there are different types of questions asked in different forms. The table given below contains the different patterns of questions asked in different exams.

Tips, Tricks, and Strategies for Human Health And Disease

It's hard to remember everything in a single go. We made the entire problem easy. Some of the tricks regarding human health and disease are given below which you can use to memorize the important points.

Types of Diseases

"DIA: Infectious, Autoimmune, Degenerative"

• D: Infectious diseases (caused by pathogens)

• I: Autoimmune diseases (immune system attacks the body)

• A: Degenerative diseases (progressive deterioration of function)

Risk Factors for Disease

"LIFE: Lifestyle, Inherited, Functional, Environmental"

• L: Lifestyle choices (diet, exercise)

• I: Inherited factors (genetic predisposition)

• F: Functional limitations (chronic conditions affecting health)

• E: Environmental factors (pollution, exposure)

Immune System Components

"B-TEA: B cells, T cells, Eosinophils, Antibodies"

• B: B cells (produce antibodies)

• T: T cells (regulate immune responses)

• E: Eosinophils (combat parasites and allergic reactions)

• A: Antibodies (proteins that identify and neutralize pathogens)

Preventive Health Measures

"DIVA: Diet, Immunizations, Visits (doctor), Activities (physical)"

• D: Healthy diet

• I: Regular immunizations

• V: Regular doctor visits for check-ups

• A: Regular physical activity

Chronic Disease Management

"CAMP: Control, Adherence, Monitoring, Prevention"

• C: Control symptoms (medication and lifestyle)

• A: Adherence to treatment plans

• M: Monitoring health status (regular check-ups)

• P: Preventing complications (education and resources)

Common Infectious Diseases

"VIP: Virus, Infection, Prevention"

• V: Viral infections (e.g., influenza, COVID-19)

• I: Bacterial infections (e.g., strep throat, tuberculosis)

• P: Prevention strategies (handwashing, vaccination)

Lifestyle Changes for Better Health

"HEAL: Healthy Eating, Exercise, Adequate Sleep, Limit Stress"

• H: Healthy eating habits

• E: Regular exercise

• A: Getting enough sleep

• L: Limiting stress through mindfulness and relaxation

Signs of Illness

"Fever, Pain, Swelling, Fatigue: "

• F: Fever (indicates infection)

• P: Pain (may signal injury or illness)

• S: Swelling (could indicate inflammation)

• F: Fatigue (may signal underlying health issues)

Prescribed Books for Human Health and Diseases

NCERT Biology textbook class 12 forms the base for learning about Human Health and Diseases. Further extended understanding of the concept can be done through "Trueman's Elementary Biology, Volume 2", which provides all essential explanations with practice questions. Another helpful book is "Pradeep's Biology" which provides proper explanations with solved examples. Other great videos, articles, and practice mock tests are available on the Careers360 website for this chapter.

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