The immune system is composed of different organs and immune cells. Here is an overview including T-Cells, Natural Killer, B Cells... I’ve said on the “Fundamentals” page that there are two types of immunity – innate and acquired. Let’s add one more fact to it by saying that both of them are maintained by a system called Lymphoreticular System which is a complex organization of Immune cells. Therefore, I’ll use the terms Lymphoreticular system and Lymphoreticular cells meaning exactly the same thing.
• There are several different systems inside your body – nervous system, blood system, immune system, digestive system and so on.
• Sometimes, one system can be part of another or there might be overlapping between them.
Lymphoreticular System - the lymphoid and reticuloendothelial systems are considered together as one system.
Reticuloendothelial System (RES) is a group of Immune cells with the ability to take up and captures inert contaminants and essential chemical dyes, such as macrophages and macrophage precedent, specialized endothelial cells coating the sinusoids in the liver organ, spleen, and bone marrow, and reticular cells or tissue of lymphatic cells and tissue (macrophages) and fibroblast (bone marrow).
Lymphoid System the lymphoid tissues in the human body is made up of (a) a main portion, such as the bone tissue marrow, thymus, as well as an unidentified part known as bursal comparable tissues; and (b) a peripheral portion comprising lymph nodes, spleen, and gut-associated lymphoid tissues (tonsils, Peyer's patches).
The reticuloendothelial system (cells) mostly consist of phagocytic cells . Their purpose would be to immerse microorganisms, and take part in inflammation. That is it!!
In one way, they help with non-specific defenses since engulfing microorganisms is kind of a standard function. However, they engage in a particular defense by presenting antigens and with cytokine secretions.
It is one major function, like a leading role this one played by the phagocytes and deficiencies causes a disorder called Chronic Granulomatous Disease.
The major phagocytic cells are:
• Neutrophils, also called Polymorphonuclear leucocytes (PMNLs), microphages.
• Blood and tissue monocytes. They both are derived from the bone marrow during hematopoiesis.
Neutrophils These Immune cells flow in the blood stream for 6-7 hours, then move throughout the endothelial cellular junctions and stay in tissue areas, the place in which they survive just for very few days plus, not increasing in numbers. Neutrophils are the most abundant leukocytes and their number may increase two to three times during active infections. A few neutrophils can stay attached to endothelial lining in larger veins and also, during inflammation, can be mobilised.
Monocytes have kidney-shaped or round-shaped nuclei presenting a perfectly granular cytoplasm, and also have half-life of Three days in blood circulation. As soon as monocytes abandon blood circulation and enter tissue, they are called macrophages . There are 2 kinds of macrophages, one which wander within the tissues spaces along with the others which are fixed to vascular endothelium of liver organ, spleen, lymph node along with other structure. Tissue macrophages live for a few months and will increase in numbers. Capabilities of macrophage involve eliminating of microorganisms, contaminated cells, tumour cells, secretion of immunomodulatory cytokines, antigen digesting and presentation to T cells. Macrophages react to microbial infection as fast as neutrophils but continue to persist considerably longer.
Lymphoid Cells (or lymphohematopoietic cells, lymphoid hematopoietic cells):
This is actually a general name for a rather large group of cells all related to the lymphoid organs, those we saw on our “immune organs” page. Lymphoid cells are derived from myeloid stem cells and include:
• T-Cells or (T lymphocytes) these immune cells are usually divided into two major subsets that are functionally and phenotypically (identifiably) different.
B Cells; The B lymphocytes main purpose is producing antibodies in reaction to unfamiliar protein of bacterias, viruses, and tumor cellular material. Antibodies are specific proteins that particularly identify and combine to a single special protein. Antibody production and binding to some unfamiliar substance or antigen, often is crucial as a way of signalling other cells to engulf, destroy or eliminate that substance from the body.
Another essential type of Immune cell is known as the T killer/suppressor subset or CD8+ T cell. They are very important cells in immediately eliminating particular tumor cells or infected by virus and often parasitic organisms. The CD8+ T cells may also be essential in down-regulation of immune answers. Each kinds of T cells can be located through the entire human body. They frequently depend upon the supplementary lymphoid organs (the lymph nodes and spleen) as sites in which triggering takes place, but they're also located in other cells in the human body, most noticeably the liver, lungs, our blood, and intestinal tract and reproductive system areas.
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