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Wandering cell

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In anatomy and histology, the term wandering cell (or ameboid cell)[1] is used to describe cells that are found in connective tissue, but are not fixed in place. This term is used occasionally and usually refers to blood leukocytes (which are not fixed and organized in solid tissue) in particular mononuclear phagocytes. Frequently, the term refers to circulating macrophages and has been used also for stationary macrophages fixed in tissues (histocytes), which are sometimes referred to as "resting wandering cells".[2]

Types of Cells

Lymphocytes: These are cells responsible for immune responses that circulate in the blood. Normally, only small numbers are found in the CTs throughout the body. The number increases dramatically at certain sites of tissue inflammation. They are also very numerous in the lamina propria of the respiratory and gastrointestinal tracts, where they are involved in immunosurveillance. The lamina propria is a layer of loose CT lying immediately beneath the epithelium.


Plasma cells: Plasma cells are derived from B-lymphocytes and produce antibodies against a specific antigen. They have a limited migratory ability and a short life.


Neutrophils: Neutrophils are white blood cells that act as phagocytes in the early stages of acute inflammation.


Eosinophils: Eosinophils are white blood cells that are found in the lamina propria of the GI tract, and at sites of allergic reaction and parasitic infection.


Basophils: Basophils are white blood cells that are similar to mast cells in having vasoactive agents released in response to an allergen.


Monocytes: Monocytes are white blood cells that will give rise to all the phagocytes of the mononuclear phagocytic system (see Ross et al., pg. 110, and Table 5.4, pg. 112). In CT, they give rise to macrophages (histiocytes).

Characteristics

Wandering Cells are probably amoeboid when alive but after fixations they are seen to posses a distinct nucleus. These cells are regarded as a special type of blood cell. The cells were found to take up iron saccharate, which had been injected into the haemocoele. The cell's cytoplasm contains a variety of inclusions and characteristically, a well-markedeosinophile area. The wandering cells of nudibranchs are excretory taking up effete mattter from the harmocoele and discharging it into the lumen of the gut.

Lymphocytes

Lymphocytes are just one group of cells that function as part of the immune system. More of this group travel around the lymphatic system than in the blood network. Two types of lymphocytes are present in the bloodstream, which are the B cells and the T cells.

B cells are wandering cells that are antibody factories. They are capable of producing molecules that can recognize and bond to specific types of molecules present in infectious organisms or substances that the body identifies as foreign. Every individual B cell makes only one particular type of antibody, specific to only one type of foreign substance. For example, where one cell produces antibody against one of the many viral causes of a cold, another cell's antibodies will ignore the presence of the same virus completely. Normally, the body contains many different B cells, specialized for a specific invader, but only has low levels of each type circulating. When an invader manages to break past other defenses, like the skin or digestive tract into the body, then the circulating B cells that target that particular foreigner multiply up and produce more antibody. Special forms of B cell called plasma cells produce antibodies; little versions of the specialized B cells, called memory B cells, remain stored in lymph glands prepared for the next invasion by the foreigner. Although the products of B cells, the antibodies, stick onto their target invader, they most often do not kill the invader. This job falls to other types of lymphocytes called T cells. There are three different forms of T cells, which are the Helper T cells, the Killer T cells, and the Suppressor T cells. [3]

See also

References

  1. ^ Template:EMedicineDictionary
  2. ^ "Connective Tissue". Retrieved 2008-11-27.
  3. ^ What Are the Different Types of Lymphocytes