Revision: 12th Std >> Human Health and Diseases MAH-MHT CET (PCM/PCB) Human Health and Diseases

Health is defined as the state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity.

The overall ability of the host to fight the disease-causing organisms conferred by the immune system is called immunity.

Infection is the entry, development, or multiplication of an infectious agent in the human body or animals.

Preparation of antigenic proteins of pathogens (weakened or killed) which on inoculation into a healthy person provides temporary/permanent immunity against a particular disease.

A preparation containing specific antigens that is administered to induce temporary or permanent immunity against a particular disease is called a vaccine.

Antibiotics are metabolic products of microorganisms whose very low concentrations are inhibitory or detrimental to other microbes.

The process of administering a vaccine to stimulate the immune system and provide protection against infectious diseases is called vaccination.

Rhesus factor is a hereditary protein present in red blood cells. If present, the individual is Rh-positive; if absent, they are Rh-negative.

Blood transfusion is the process of introducing blood from a healthy donor into the bloodstream of a patient, typically through a vein, often during surgery or after heavy blood loss.

A Blood Recipient is a person who receives blood during a transfusion, requiring compatibility with the donor's blood group.

Antigens are specific proteins present on the surface of red blood cells that determine an individual’s blood group (e.g., Antigen A or Antigen B).

Antibodies are proteins present in blood plasma that react against specific antigens not found on the individual's own red blood cells, playing a key role in blood group compatibility.

A person with blood group AB is called a universal recipient because they can receive blood from all major blood groups (A, B, AB, and O) without risk of incompatibility.

A pathogen is a biological agent that causes disease to its host. e.g. bacteria, virus, etc.

Disease:
The disease can be defined as an impairment or malfunctioning of the normal state of the living organism that disturbs or modifies the performance of vital functions of the body.

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

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

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

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

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

Agents that cause cancer by disturbing the normal genetic and regulatory processes of cells are called carcinogens.

A cancer-causing gene that induces transformation of normal cells into cancerous cells is called an oncogene.

A normal cellular gene involved in growth and development, which can become an oncogene after mutation or activation, is called a proto-oncogene.

Adolescence is the period between the beginning of sexual maturation and entry into adult life.

Addiction is a condition of physical and psychological dependence on a substance or habit, leading to compulsive use despite harmful effects.

Drug abuse is the improper or excessive use of drugs that leads to harmful effects on physical, mental and social health.

1. Blood transfusion involves transferring blood from a healthy donor to a patient and requires strict blood group compatibility.
2. The ABO system divides blood into four types—A, B, AB, and O—based on antigens present on RBCs and corresponding antibodies in plasma.
3. Blood group O is known as the universal donor, while group AB is the universal recipient due to compatibility with all types.
4. The Rh system is based on the presence (Rh⁺) or absence (Rh⁻) of the Rh factor (D antigen) on RBCs, discovered in Rhesus monkeys.
5. Rh incompatibility in pregnancy may lead to the mother's sensitisation, causing complications for future Rh⁺ pregnancies, including foetal death or abortion.

• Adolescence is the stage between childhood and adulthood (ages 10–19), marked by fast physical and emotional changes.
• It has three stages: Early (10–14), Middle (15–17), and Late (18–19), each with different body and thinking developments.
• Puberty brings sexual and physical changes due to hormones—testosterone in boys and oestrogen in girls.
• Physical changes include growth in height, changes in body shape, changes in voice, and increased sweat/oil production.
• Emotional and social changes include mood swings, seeking independence, peer pressure, and identity formation.