Revision: Biology and Human Welfare >> Human Health and Diseases CUET (UG) Human Health and Diseases

Autoimmunity is the condition in which the immune system fails to recognise self and reacts against the body’s own cells and tissues.

Autoimmune response is an immune reaction in which antibodies or immune cells are produced against the body’s own antigens.

Autoimmune disease is a pathological condition caused due to autoimmunity, where self-tissues are damaged or destroyed by the immune system.

Cancer is a disease characterised by uncontrolled and abnormal division of body cells due to loss of normal growth regulation.

Metastasis is the process by which cancer cells spread from the primary site to distant organs through blood or lymph.

Tumour is a mass of abnormally proliferating cells formed due to uncontrolled cell division.

Malignant tumour is a cancerous tumour that grows rapidly, invades surrounding tissues and spreads to distant organs.

Benign tumour is a non-cancerous tumour that remains confined to its original site and does not spread to other parts of the body.

• Health is a state of complete physical, mental, and social well-being — not just the absence of disease.
• Health is affected by genetic disorders, infections from microbes, and lifestyle (food, water, exercise, rest).
• Good health is maintained by a balanced diet, personal hygiene, regular exercise, immunisation, and vector control.
• Diseases are of two types: infectious (transmitted person to person) and non-infectious (cannot be transmitted).
• Disease-causing organisms are called pathogens - they include bacteria, viruses, fungi, protozoans, and helminths.
• Pathogens enter the body, multiply, and disrupt vital functions; they adapt to the host environment (e.g., survive low pH in the gut).

• Autoimmunity is a condition where the immune system loses its ability to distinguish between "self" and "non-self" cells, mistakenly targeting the body's own tissues.
• An autoimmune response is a specific abnormal reaction in which the body actively produces antibodies or immune cells directed against its own self-antigens.
• Autoimmune disease is the resulting pathological condition where this misdirected immune response causes actual physical damage and destruction to self-tissues.
• Common examples include Rheumatoid arthritis, Hashimoto’s disease (targeting the thyroid), myasthenia gravis (targeting muscles), Addison’s disease, and chronic anaemia (targeting red blood cells).