RBSE Class 12 Biology Notes Chapter 8 Human Health and Disease

These comprehensive RBSE Class 12 Biology Notes Chapter 8 Human Health and Disease will give a brief overview of all the concepts.

RBSE Class 12 Biology Chapter 8 Notes Human Health and Disease

→ Health is a state of complete physical, mental and social well being and not merely an ‘absence of disease’ or “physical fitness.” Health is state of body when all the organs and system are functioning properly and perfect balance is maintained between the environment and the body.

→ Disease involves adversely affected functioning of one or more organs or systems of the body which is characterised by various signs and symptoms.

→ Diseases may by broadly classified into two types:

1. Congenital diseases: easily transmit form one person to another.
2. Acquired diseases: do not transmit from one person to another.

→ Acquired diseases are further classified into infectious or communicable diseases and non-infectious or non-communicable diseases.

→ Any substance, or factor which causes a disease by its excess or deficiency or absence, is called a disease agent.

→ Pathogen: Disease causing organisms are called pathogens e.g. viruses, bacteria, fungi etc.

→ Thyroid is an infectious disease caused by a bacterium Salmonella typhi. It is diagnosed by widal test.

→ Pheumonia is a serious bacterial disease, caused by Streptococcus pneumoniae.

→ Common Cold is a viral disease caused by Rhino Virus.

→ Malaria is the most common and most destructive disease of human beings. It is caused by species of Plasmodium and spreaded by female Anopheles mosquitoes.

→ Amoebiasis is caused by Entamoeba histolytica, Ascariasis' by Ascaris lumbricoides, Filariasis by Wuchereria brancrofti and Ringworm by Trichophyton.

→ The ability of the body of on organism to resist the development of a disease is called immunity. The study of immunity is called immunology.

→ Immunity is mainly of two types: 1. Innate immunity and 2. Acquired immunity. The immunity which present from the birth of an organism is called innate immunity while that acquired after birth is called acquired immunity.

→ Physical and physiological barriers consist the external defence to the entry of pathogens into the body.
 
→ There are two main components that are found in acquired immune system - antibody mediated immune system (AMIS) and cell mediated immune system (CMIS).    

→ Acquired immunity is of two type Active immunity and Passive immunity.

→ the process of introducing a vaccine in the body to develop immunity against a particular disease or pathogen is called Vaccination. Vaccine is a suspension or extract of a dead or attenuated germs of a disease which on infection into a healthy person provides temporary or permanent, active/passive immunity by inducing formation of antibodies.

→ Allergy is the hyper sensitivity of immune system of a person to some foreign substances or any antigen which either comes in contact with or enter to body.

→ AIDS is an incurable viral disease caused by Human Immuno Deficiency Virus (HIV). It can be diagnosed by ELISA test.

→ Cancer is characterised by uncontrolled growth and division of certain body cells or tissues, so forming a turner.

→ Sarcoma, carcinoma, melanoma and Leukaemia are the types of cancer.

→ The physical and mental dependency on smoking, alcohol and drugs is called addiction.

→ Chemical or other substance which has a physiological effects when ingested or otherwise introduced into the body called drug.

→ Drugs, Tobacco, alcohol etc. cause addiction, when they are used for a long time.

→ Health: A state of complete physical, mental and social well being.

→ Disease: A state of malfunctioning of certain body organs and impairment of health.

→ Pathogen: Disease causing organism.

→ Vector: The agents which spread disease are called vectors.

→ Immunity: The power of body to fight against disease.

→ Cancer: Uncontrolled division of cells, gives rise to tumor.

→ Biopsy: An examination of tissue removed from a living body to discover the presence, cause or extent of a disease.

→ Addiction: Dependency on alcohol or smoking or drugs. 

→ Allergy: Hyper sensitivity of of body to some external agents called allergens.

→ Analgesics: Pain killer chemicals.

→ Carcinogens: Cancer-causing physical and chemical agents.

→ Depressants: Chemicals which lower the activity of CNS.

→ Hallucinogens: Chemical which cause hallucination (seeing objects which are not present).

→ Metastasis: Spread of cancer from one organ to other organ of body.

→ Sedative: Chemical which decrease the activity of CNS.

→ Stimulants: Chemical which increase the activity of CNS.    .

→ Vaccine: An inoculation stimulating the production of antibodies in the body.

→ Antigen: A foreign particle which induces antibody formation when introduces to the body.

→ Antibody: Defensive proteinous compounds which acts against the antigens.

→ Opiates: Chemical drived from opium.

→ Vaccination: The process of introduction of weakened or inactivated pathogens or vaccines into a person to provide protection against diseases.

→ Tumor: The repeated division'of cancerous cells form a larger mass of cells, called tomors.

→ Radiography: Detection of any disorder in the internal organs.