Revision: Human Health and Diseases Biology HSC Science (General) 12th Standard Board Exam Maharashtra State Board

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.

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

Vector:
Vector is an agent that acts as an intermediate carrier of the pathogen.

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.

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.

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

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.

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

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

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.

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

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.

• 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.

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.