What is the immune system?
The immune system is a network of special cells, proteins, tissues, and organs that work together, helping the body defend against germs, microorganisms and other invaders. Without the immune system, we will be at risk since those foreign agents would attack our body system and cause diseases.
Components of an immune system
An immune system consists of many components, ranging from cells to organs. One of the most crucial cells in that network are white blood cells (leukocytes).
Leukocytes are made or stored in various places in the body, including the thymus, spleen, and bone marrow, making these organs also known as lymphoid organs. Other times, leukocytes are stored in clumps of lymphoid tissue (lymph nodes) that scatter throughout the body.
The leukocytes travel all around the body via lymphatic vessels and blood vessels, monitoring it any possibly harmful invaders.
There are two basic types of leukocytes which combine to search for and kill disease-causing organisms or substances. They are:
- Lymphocytes: cells that help the body remember and recognize previous invaders. Lymphocytes also help in destroying those invaders.
- Phagocytes: cells that eat up invaders
There are a number of different types of cells that are considered phagocytes. Each type phagocytes have their own jobs. For example, the most common type is the neutrophil, whose job is to fight bacteria.
There are two types of lymphocytes, which are B lymphocytes and T lymphocytes. Born in the bone marrow, lymphocytes later either stay there and mature into B cells, or move to the thymus gland and mature into T cells.
B lymphocytes and T lymphocytes have different functions. While B lymphocytes seek out their targets and send defenses to lock onto them. T cells destroy the invaders that identified by the intelligence system.
How does the immune system work?
Foreign microorganisms and substances that invade the body are called antigens. When antigens are detected, a series of immune responds will happen to protect the body from being infected.
In that process, several types of cells work together to recognize antigens and respond. These cells then stimulate the B lymphocytes to produce antibodies. Antibodies are proteins specially designed to stick onto specific antigens. After that, T cells seek for the tagged antigens and destroy them. T cells also help to signal other cells (like phagocytes) to do their jobs.
What’s more about antibodies? Once produced, they present in a person’s body for some more time, so if the antigen ever comes back, the antibodies are already there to do their mission.
Antibodies also can neutralize toxins produced by organisms and activate a group of proteins called complement. Complement is part of the immune system that assists in killing bacteria, viruses, or infected cells.
Togerther, all of these specialized cells and parts of the immune system bring about the body protection against disease. This protection is what we call immunity.
Hello Health Group does not provide medical advice, diagnosis or treatment.
Review Date: October 16, 2017 | Last Modified: September 11, 2019