Human Health and Disease

Human Health and Disease

Edited By Irshad Anwar | Updated on Jun 09, 2025 07:46 AM IST

The chapter Human Health and Disease aims to comprehend the biological underpinnings of health by the World Health Organisation's definition, which encompasses physical, mental, and social well-being. It encompasses a broad spectrum of diseases that include the aetiology, clinical manifestations, and mode of transmission of bacteria, viruses, protozoa, and fungi-related communicable diseases. Preventive measures like vaccination, personal hygiene, and public sanitation are highlighted as major tools of disease control.

This Story also Contains
  1. Important Topics of Human Health and Diseases
  2. What is Health?
  3. What is Disease?
  4. Common Human Diseases
  5. Immunity
  6. Alcohol and Drug Abuse
Human Health and Disease
Human Health and Disease


Moreover, the chapter discusses the immune system extensively, making a distinction between innate and acquired immunity and reviewing immune-related illnesses like allergies, autoimmunity, and AIDS. It also emphasises the role played by lifestyle in health, such as the physiological consequences of drug abuse and causation of non-communicable diseases like cancer. Such information serves as a foundation for spreading health consciousness and creating improved strategies of preventing diseases and controlling them.

Important Topics of Human Health and Diseases

Human Health and Diseases is a must for understanding how the body protects itself and reacts to different internal and external threats. The matter includes significant areas such as the categorisation and etiology of diseases, mechanisms of immunity, categories of pathogens, modes of transmission of disease, and prevention and treatment methods. It also covers disorders related to lifestyle, the physiology of addiction, cancer, and the consequences of drug and alcohol abuse. These subjects give an overall idea about how health is being preserved and how different factors cause illness and disease.

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

Health can be defined as a state of well-being where an individual feels body, mind, and social well-being. It is not only the absence of disease but also having the energy and ability to enjoy life to the fullest. Good health is dependent upon healthy nutrition, staying active, getting ample rest, and managing stress. It also has to do with living in a clean environment and avoiding bad habits.

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

ComponentExplanation
NutritionProvides essential nutrients that fuel body functions and maintain health.
Physical ActivityEnhances cardiovascular health, strengthens muscles, and improves flexibility.
SleepHelps restore the body and supports mental and emotional well-being.
HygienePrevents infections and diseases by maintaining cleanliness and sanitation.


Factors Affecting Mental Health

FactorExplanation
StressChronic stress can lead to conditions like anxiety, depression, and burnout.
LifestylePoor diet, lack of exercise, and substance abuse negatively impact mental health.
TraumaPast trauma or abuse increases the risk of developing mental disorders.
GeneticsFamily history of mental illness can predispose individuals to similar conditions.
EnvironmentUnhealthy surroundings or chronic illnesses can affect emotional well-being.
Brain ChemistryImbalance in neurotransmitters like serotonin or dopamine may cause disorders.
Cognitive HealthRegular mental activity supports memory, attention, and overall brain function.


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What is Disease?

A disease is a condition that causes the body or mind to perform abnormally. It results from some form of abnormality in the body, such as an infection, injury, or imbalance. Diseases can be caused by microbes, such as bacteria or viruses, unhealthy habits, or genes passed from parents. Some diseases are short-lived, such as the flu, and others, such as diabetes, last longer. Treatment and prevention also vary according to the disease.

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:

Congenital

Acquired

  • Conditions which are present since birth due to environmental factors during pregnancy.

  • Diseases which are developed during any stage at personal lifetime and are known as acquired disease

  • Genetic mutation, chromosomal abnormalities, environmental influences and exposure to drugs are causes of congenital diseases.

  • Infection, lifestyle Choices, ageing and immune system dysfunction are some common causes.

  • Down Syndrome, Cystic fibrosis, and congenital heart are some basic examples

  • Diabetes, Tuberculosis, hypertension and cancer are some of the basic examples.

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:

Disease

Symptoms

Causes

Preventive Measures

Malaria

Fever, chills, sweating, headache, nausea

Plasmodium parasite transmitted by Anopheles mosquitoes

Use insect repellent, mosquito nets, and antimalarial drugs

AIDS

Weak immune system, opportunistic infections, weight loss, fatigue

Human Immunodeficiency Virus (HIV)

Safe sex practices, avoid sharing needles, antiretroviral therapy (ART)

Tuberculosis (TB)

Persistent cough, chest pain, night sweats, weight loss

Mycobacterium tuberculosis bacteria

BCG vaccination, good ventilation, proper treatment of active TB cases


Cancer

Variations by type can include lumps, abnormal bleeding, weight loss, and fatigue

Genetic mutations, lifestyle factors (smoking, diet), environmental exposures

Regular screenings, healthy lifestyle, avoiding carcinogens

Diabetes

Increased thirst, frequent urination, fatigue, and blurred vision

Insufficient insulin production (Type 1) or insulin resistance (Type 2)

Healthy diet, regular exercise, maintaining a healthy weight, and monitoring blood sugar levels


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.

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.

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:

Tumor Type

Description

Characteristics

Causes of Cancer

  • Benign tumour

  • Non- Cancerous and slow-growing tumour

  • Do not spread to the other tissues

  • Genetic mutation

  • Malignant tumour

  • Cancerous and fast-growing tumour. Also, have the capability of metastasis.

  • Spread via blood and lymph to the other organs

  • Radiation, chemical exposure, virus, lifestyle, environmental factors and immune dysfunction.

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.

Other useful Resources

Frequently Asked Questions (FAQs)

1. What are the Key concepts in Human Health and Disease in Chapter?

The key concepts in human health and disease are the types of diseases, common infectious diseases, infections, AIDS, cancer, etc.

2. What are the different ways of transmitting the Human Immunodeficiency Virus?

Different ways of transmitting the virus are through sexual contact, blood transfusions of infected people and the use of one needle for more than one person.

3. What is called the treatment and study of Neoplasms?

The field of neoplasm - benign and malignant research is known as oncology.

4. What are the types of innate immunity?
  • Physical barrier
  • Physiological barrier
  • Cellular barrier
  • Cytokine barrier
5. Name the virus that causes AIDS.

The Human ImmunoDeficiency Virus (HIV) is responsible for causing AIDS. 

6. Write about the types of disease.

Human diseases fall into two categories:

Congenital: A condition that has existed since birth

Acquired: Disease that occurs during a person's lifetime

7. Why is it important to wash hands before eating?

Washing hands before meals protects one from pathogens that may transmit infectious diseases and helps the individual to be much healthier and cleaner.

8. What are the main factors affecting physical health?

Physical health can be influenced by key aspects: nutrition, physical activity, sleep, and hygiene.

9. What is the difference between infectious and non-infectious diseases?

Infectious diseases are Pathogens and contagious from one individual to another. On the other hand, non-infectious diseases are not transmitted from person to person. The latter is mostly caused by genetic or environmental factors and/or the result of bad habits in day-to-day life.

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