Human Diseases in Biology are categorized into various types such as Infectious (Communicable), Non-Infectious, Genetic, Deficiency, Lifestyle, Autoimmune, and Environmental diseases. Studying these diseases helps us understand their causes, effects on the body, and ways to prevent or manage them for a healthier life.
Human diseases
Previous year Questions
| Year | Question | Marks |
| 2023 | What is “Shree anna”? Why are they considered to be the nutri-cereals ? Describe the digestive-glands and their secretions which are associated with alimentary-canal in Human-beings. | 10M |
| 2023 | What is “DNA Vaccine” ? Name the world’s first Covid-19 “DNA Vaccine”. | 2M |
| 2018 | What are the causes of communicable diseases ?(b) Classify following diseases as communicable and noncommunicable diseases.(i) Alzheimers(ii) Trachoma(iii) Cholera(iv) Asthma(v) Rabbies | 5M |
| 2018 | Give a brief account of Acquired Immunity and its types. | 5M |
| 2016 special | Write the name of causal organism and vector of ‘Dengue fever’. | 2M |
| 2016 special exam | What are chromosomal disorders in human beings ? Write causes and symptoms of any two such disorders. | 10M |
Evolution of Health and Disease
- Early Concepts of Health:
- Health was once thought to be the balance of bodily fluids (humors), as proposed by Hippocrates and the Ayurvedic system. For example, excess “black bile” was linked to fevers and certain personality traits.
- Scientific Advancements:
- William Harvey discovered blood circulation, challenging the humoral theory.
- The invention of the thermometer disproved the idea that people with “black bile” had abnormal body temperatures.
- Modern Understanding:
- Today, health is defined as physical, mental, and social well-being, not just the absence of disease.
- The immune system plays a key role in health, influenced by mental and physical factors like the nervousand endocrine systems.
Types of Diseases
Infectious Diseases(Communicable) :
Infectious diseases are caused by harmful microorganisms such as bacteria, viruses, fungi, and parasites. These diseases can spread directly or indirectly from person to person.
- Transmission: These diseases can spread through:
- Air (e.g., flu, tuberculosis)
- Water (e.g., cholera, typhoid)
- Bodily fluids (e.g., HIV/AIDS, hepatitis)
- Contaminated food (e.g., food poisoning, salmonella)
- Insects (e.g., malaria, dengue)
- Examples: Flu (Influenza), Tuberculosis (TB), HIV/AIDS, Malaria.
Non-Infectious Diseases
Non-infectious diseases are not caused by pathogens and cannot be spread from person to person. They often develop over time due to lifestyle factors, genetics, or environmental influences.
- Examples:
- Cancer, Heart Disease, Diabetes, Hypertension (High Blood Pressure)
Genetic Disorders
- Genetic disorders are diseases caused by abnormalities in an individual’s genetic material (DNA). These disorders can be inherited from parents or occur spontaneously
- Types of Genetic Disorders:
- Single-gene disorders: Caused by mutations in one gene (e.g., cystic fibrosis, sickle cell anemia).
- Chromosomal disorders: Involve changes in chromosome number or structure (e.g., Down syndrome, Turner syndrome).
- Multifactorial disorders: Caused by a combination of genetic predisposition and environmental factors (e.g., heart disease, diabetes).
- Examples:
- Cystic Fibrosis: Affects the lungs and digestive system, causing thick mucus buildup.
- Sickle Cell Anemia: Red blood cells become misshapen, leading to blockages and pain.
- Down Syndrome: When a person has an extra chromosome 21, leading to intellectual disabilities and physical abnormalities.
Deficiency Diseases
Deficiency diseases occur when the body lacks essential nutrients required for proper function. These diseases are preventable by ensuring a balanced diet.
- Examples:
- Scurvy: Caused by a lack of vitamin C. Symptoms include bleeding gums, weakness, and fatigue.
- Rickets: A condition caused by a lack of vitamin D, leading to weakened bones and skeletal deformities.
- Anemia: Often caused by a lack of iron, leading to symptoms like fatigue, weakness, and pallor.
Lifestyle Diseases
Lifestyle diseases are primarily influenced by habits such as poor diet, lack of physical activity, smoking, and excessive alcohol consumption. These diseases are preventable by adopting healthy habits.
- Examples:
- Obesity
- Chronic Respiratory Diseases: Conditions like chronic obstructive pulmonary disease (COPD) and asthma are often linked to smoking or environmental pollutants.
- Drug and Alcohol Abuse.
Autoimmune Diseases
Autoimmune diseases occur when the body’s immune system mistakenly attacks its own healthy cells and tissues.
- Examples:
- Rheumatoid Arthritis: An autoimmune disorder that causes inflammation in the joints.
- Multiple Sclerosis: A disease where the immune system attacks the protective covering of nerve fibers, leading to nerve damage.
- Type 1 Diabetes: The immune system destroys insulin-producing cells in the pancreas.
Environmental Diseases
These are diseases caused or triggered by environmental factors such as pollution, chemicals, or radiation.
- Examples:
- Asthma: Can be triggered by air pollution, allergens, and smoke.
- Skin Cancer: Caused by excessive exposure to ultraviolet (UV) radiation from the sun or tanning beds.
- Lead Poisoning: Can occur from exposure to lead-based paints, contaminated water, or soil.
