Types of Leukocytes

Leukocyte is another name for white blood cells. There are different types of leukocytes that exist in our body, each having a significant function of their own. This Buzzle article discusses the various kinds and functions of each kind.
Leukocytes, which is an alternate name for white blood cells, are responsible for a stronger immune system of the body. They are present throughout our body, including the blood and lymphatic system, to safeguard our body from infectious diseases and unknown bodies that enter our system to harm us. Leukocytes form a total of approximately 1% of the blood in an adult's body, which if converted into numerals, are somewhere around 4x109 and 1.1x1010 in a liter of blood. There are 5 types of leukocytes that exist in the body, which will be explained as the article proceeds further. If the number of leukocytes are more than the upper limit required in the body, the condition is known as leukocytosis, and if the leukocytes are less than the lower limit required by the body, the condition is known as leukopenia. Neither of the conditions are good for the body. Therefore, it is very important for a person to have, and know the normal values of leukocytes, in order to lead a healthy life.

Types of Leukocytes and their Functions

As mentioned earlier, there are 5 different types of leukocytes, and all of them play a vital role in the defense mechanism of the body. All of these have similar properties but distinct functions and features.

These leukocytes are the first ones to fight against a potential microbial infection. Also known as Neutrophil granulocyte or polymorphonuclear leukocytes (PMN), these are responsible for defending the body from bacterial infections and fungal infections and diseases. They are also found in huge numbers in the pus of the wounds in our body. They have a lifespan of 6 hours to a few days and are about 10-12 micrometers in size.

These leukocytes are the ones that handle parasitic infection along with hives, allergic reactions, asthma and hay fever. They circulate in the body for an average of 4-5 hours and have a lifespan of 8-12 days. Like Neutrophil, even these have a size of 10-12 micrometers.

Leukocytes are present all throughout the body, including the lymphatic system, and the lymphocytes are found there. The blood consists of 3 kinds of lymphocytes which are discussed as under.
  • B Cells: These play a vital role in binding the pathogens to destroy them and produce antibodies.
  • T Cells: These are further categorized into 3 kinds. The CD4+ which identify the immune system activities and co-ordinate to fight against intracellular bacteria, the CD8+ cytotoxic T cells which destroy tumor and virus infected cells.
  • γδ T cells: These cells act as helper cells to identify the threat and kill the infected cells in the body. The sizes of these cells vary from 7-8 micrometers and they can live from weeks to years.
Monocytes perform the function of a 'vacuum cleaner' by collecting the pieces of pathogens and allowing the T cells to destroy them. They also flow through the blood stream and remove debris of dead cells present in the blood. They can live for hours to days and are 14-17 micrometer in size.

These leukocytes release a chemical known as histamine is response to antigen and allergic threat which causes inflammation. These are approximately 12-15 micrometers in size and can live from a few hours to a few days.

Isn't it wonderful to know how different antibodies are constantly working to keep us safe from the external threats of diseases and infections that we are surrounded by. So, take care of yourself by following a healthy and balanced diet. Also make sure that you exercise regularly as that too contributes in making your immune system stronger. Make sure you do all you can to help the antibodies within your body, build a better defense mechanism. Take care.
By Shalu Bhatti
Last Updated: 10/10/2011
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