Human bodies require an immune system in order to resist or fight any attacks that are posed by diseases. There are organs that are charged with this task and they produce the lymphocytes in order to fight virus, tumor cells and bacteria. The body immune system is made up of the immune organs which are made up of several cells that help in killing parasitic cells and tumor. The following are some of the immune organs:
1. Bone marrow
All the cells of the immune system are created here through a process that is commonly known as hematopoiesis. They are found within the bones. Cells such as natural killer cells, granulocytes, B cells and immature thymocytes, are produced in the bone marrow. Red blood cells as well as platelets are also produced in the bone marrow.
2. Thymus glands
This is another place where immune system cells are produced. This gland is found in the chest region and it is active in producing lymphocytes. It produces mature T cells. When immature cells are produced in the bone marrow, they migrate to the thymus gland to undergo the maturation process.
This is composed of immune cells such as B cells, dendritic cells, red blood cells, natural killer, T cells and macrophages. This organ filters the blood to get rid of foreign objects that are also known as antigens. The dendritic cells bring these antigens to the spleen and the B cells get activated to produce very large levels of antibodies. Old red bloods cells are also destructed here.
4. Lymph nodes
These nodes help in filtering of the interstitial fluid that is found between the cells of human bodies. B cells, macrophages, T cells and dendritic cells are found here. They filter out the antigens that are found in the body tissues.
The different immune system cells are described as follows:
• T cells
These cells intensify the responses of human body immune system. They secret some factors which activate white blood cells to fight infections.
• B cells
They are known for being active in antibody production. Antibodies are produced in response to viruses, bacteria and tumor cells.
• Natural killer cells
They act as effector cells and they destroy viral infected and tumor cells.
They are composed of eosinophils, neutrophils and basophils cells. They remove bacteria and parasites from human body.
They pick up foreign substances, ingest them and present them to B and T cells of the body immune system.