Immune System

The Immune System (/ɪˈmjuːn ˈsɪstəm/) is a complex network of cells, tissues, and organs that work together to defend the body against harmful invaders such as bacteria, viruses, and disease-causing parasites.

Etymology

The term "immune" comes from the Latin word "immunis," which means "exempt," referring to the body's ability to protect itself from harmful substances. The term "system" comes from the Greek word "systēma," which means "a whole compounded of several parts."

Function

The primary function of the Immune System is to identify and eliminate pathogens. It does this through a series of steps known as the immune response. This involves the recognition of foreign substances, the activation of immune cells, and the production of antibodies or cells to neutralize or destroy these substances.

Components

The Immune System is composed of various components, including:

White Blood Cells: These are the key players in the immune response. They are produced in the bone marrow and circulate in the bloodstream and lymphatic system.
Antibodies: These are proteins produced by the immune system to neutralize or destroy pathogens.
Lymphatic System: This is a network of vessels and nodes that carry a clear fluid called lymph, which contains white blood cells.
Spleen: This organ filters the blood and removes old or damaged blood cells. It also produces white blood cells and antibodies.
Thymus: This is where T cells (a type of white blood cell) mature and become able to recognize and respond to pathogens.

Related Terms

Inflammation: This is a response of the immune system to injury or infection, characterized by redness, heat, swelling, and pain.
Autoimmune Disease: This is a condition in which the immune system mistakenly attacks the body's own cells.
Immunodeficiency: This is a state in which the immune system's ability to fight infectious disease is compromised or entirely absent.
Vaccine: This is a substance used to stimulate the immune system to produce immunity to a specific disease.