Types of White Blood Cells

White blood cells are defined as nearly colorless cells of the immune system that circulate in the blood and lymph and participate in reactions to invading microorganisms or foreign particles entering into the body. White blood cells are produced from a cell in the bone barrow known as the hematopoietic stem cell. White blood cells are found throughout the entire body, including in the blood stream and lymphatic system.

Types

• There are five types of white blood cells, which all work together to ensure a healthy immune system. The five types are neutrophils, eosinophils, basophils, lymphocytes, and monocytes. There are three types of lymphocyte found in the bloodstream, B- lymphocytes, T-lymphocyte and natural killer cells. B-lymphocytes make antibodies, which bind to the pathogens to ensure their destruction. T -lymphocyte cells recognize foreign antigens on the surface of other cells. They then stimulate the B-lymphocyte cells to produce antibodies. Natural killer cells are able to kill cells of the body which are displaying a signal to kill them, such as cancerous cells.

Function

• Neutrophils defend the body against bacterial or fungal infections and are usually the first responders to microbial infections. Eosinophils deal with parasitic infections. An increase in eosinophils usualy will indicate to a physician that there is a parasitic infection present. Basophils, the least common, are responsible for allergic and antigen responses of the body by releasing histamine causing inflammation. Lymphocytes are the most common white blood cell in children and the second most common in adults. Lymphocytes numbers increase in response to viral infections within the body. Monocytes form in the bone marrow and spleen, and circulate to ingest large foreign particles and cell debris. Monocytes serve an important function as they provide pathogens to T- lymphocytes. This is so the pathogens can be recognized upon entering the body and killed.

Identification

• Neutrophils' cytoplasm looks transparent because of fine granuels that are a very light shade of pink. The cytoplasm of eosinophils is full of granuels which create a pink-orange color. The nucleus is hard to see because of the number of coarse, large blue granules, which hide it. A normal lymphocyte has a large, dark-staining nucleus with little to no visible cytoplasm. Monocytes are the largest and have a kidney shaped nucleus, which is agranulated, with an abundant cytoplasm.

Time Frame

• The white blood cells have a rather short life cycle, living from a few days to a few weeks. Neutrophils cells are not able to renew and die shortly after disposing a few invading bacteria. Eosinophils act as the predominant inflammatory cell in allergic reactions within the body; they are not able to renew, exiting the body after a day or two. Basofils respond to specific allergens and shortly after die off. The longest life span of the white blood cells are found in lymphocyte and monocytes. They are able to renew themselves until the job is done, usually lasting a few weeks in the body.

Warnings

• A single drop of blood can contain anywhere from 7,000 to 25,000 white blood cells at any given time. When an invading infection persists, the number of white blood cells will increase signifcantly. A consistently high number of white blood cells is a symptom of Leukemia. A patient with Leukemia can have as many as 50,000 white blood cells in a drop of blood. The basophils response to specific allergens is the rapid release of histamine; when the allergen is persistant more histamine will be released. This process is known as immediate hypersentivitiy and can result in hay fever, rash and anaphylactic shock. It's best to have regular checkups and blood work with a physician to prevent any complications from infections in white blood cells.