White blood cells or leukocytes are a vital component of the blood system that protects the body against infection and disease. These cells are actually colorless and a special dye is used to make them colored and visible under the microscope.
White blood cells are the largest blood cell and they move about by sticking out part of their body and dragging the rest of the body along. They are considered as the soldiers of the blood as they aggressively combat bacteria and other toxins that are aliens to the body. White blood cells are capable of travelling efficiently through tiny blood vessels, allowing smooth entrance to other tissues that are being affected by unfamiliar assailants.
The formation of most white blood cells occurs in the red marrow of the bone while some are also manufactured in special glands in the body. In a healthy person, there are between 4,000 and 11,000 white blood cells in a single cubic inch of blood. When the body gets an infection, it communicates with the bone marrow and special glands to produce more white blood cells. By calculating the count of the white blood cells in someone’s blood, a doctor can tell if there is an infection.
There are 5 types of white blood cells namely neutrophils, lymphocytes, monocytes, eosinophils and basophils. These 5 types are further categorized into 2 main groups: The Granulocytes and The Mononuclear Cells.
Types of White Blood Cells
Following are the 5 different types of white blood cells:
Almost half of the white blood cells are neutrophils. These are usually the first respondents of the immune system in case of an invasion by a bacteria or a virus. First to arrive at the scene, they also transmit signals to other cells in the immune system and alerting them to respond. We know the appearance of neutrophils as these are the primary cells of pus. The life span of neutrophils is around 8 hours soon after releasing from the bone marrow, and approximately 100 billion of these cells are manufactured in the body each day.
Eosinophils also play a vital role to combat bacteria and to respond to infections with parasites, such as worms. Perhaps their role in allergy symptoms is best known when eosinophils essentially go overboard in mounting an immune response against something foreign such as pollen which it mistakenly takes as an invader. There are only around 1 percent of these in the white blood cells but they also reside in high amounts in the digestive tract.
Basophils are also important in mounting a general immune response to pathogens, and account to around 1 percent of white blood cells. These cells play a critical role in asthma. When triggered, basophils produce histamine among other chemicals, resulting in the inflammation and bronchoconstriction in the air path.
Lymphocytes also play a highly important role in the immune system of the body, with T lymphocytes or T cells are dedicated to directly attack and kill foreign invaders. B lymphocytes or B cells, in contrast, are mainly responsible for humoral immunity. They produce the antibodies that keep memory of an infection and remain alert in case the body is re-exposed. B cells play an important role in the value of the most of the vaccines in current use, but in some cases such as tuberculosis and pertussis vaccines, T cells are also very important.
Monocytes are the garbage trucks of the immune system, and account to 5 percent of white blood cells in the bloodstream. Among other functions, these are responsible of migrating to other tissues and cleaning up dead cells.