WHITE BLOOD CELLS

introduction

The blood consists on the one hand of one liquid part, the Blood plasma, and on the other solid components, the Blood cells.

There are three major groups of cells in the blood:

the red blood cells (Erythrocytes),
the white blood cells (Leukocytes)
and the Platelets (Platelets),

each of which has specific characteristics and fulfills very important tasks for our body and our survival. The leukocytes have an essential function in the immune defense of the human body, whereby some cells are counted as unspecific and others as part of the specific immune system.

Properties of white blood cells

The white blood cells is called white because, unlike erythrocytes, they are not the red dye hemoglobin contain, which is why they appear whitish next to them.
Depending on their type, they can vary greatly in size.
The smallest white blood cells that Lymphocytes, are about the size of the red blood cells, about 7 µm, the largest ones Monocytes, reach sizes of up to 20 µm.
They survive anywhere from a few days to several months.

Read more about the topic here Tasks from the blood

Illustration white blood cells

Leukocytes -
white blood cells
White blood cells

A - granulocytes
(Granule cells)
A1 - neutrophils
Granulocytes (50-70%)
A2 - eosinophils
Granulocytes (2-4%)
A3 - basophils
Granulocytes (0-1%)
B - monocytes
(2-8%)
C - lymphocytes
(20-45%)
T - lymphocytes
B - lymphocytes
NK cells

You can find an overview of all Dr-Gumpert images at: medical illustrations

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development

The development of the leukocytes begins in the redden Bone marrowwhich is found in adults in Sternum and in Iliac crest is located.
In children, this red bone marrow is also found in the long tubular bones of legs and arms.
The formation of white blood cells takes place here from Stem cells.
These further differentiate, with always one Progenitor cell (a determined stem cell, which is already going in a certain direction, so to speak) and another original stem cell emerges, which is able to divide again and develop further in every possible direction (pluripotent).
The different blood cells then develop from the precursor cell, depending on the growth factors that act on the cell.
The Granulocytes originate, just like blood platelets and erythrocytes, of myeloid stem cell, the Lymphocytes of the lymphoid stem cell.

After they are formed, some white blood cells have to travel to another organ to be imprinted before they can do their job.
This Embossing mainly found in Thymus and Bone marrow, but also in the spleen, the Lymph nodes and the Almonds instead of.
There the leukocytes “learn” which substances / cells belong to the body and are therefore harmless and which are regarded as foreign and must therefore be fought.

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Reference ranges

A healthy adult owns on average 4,000 to 10,000 white blood cells per µl of blood.
Values above are called one Leukocytosis, with values below that one speaks of Leukopenia.
This total number can be broken down further into the different types of white blood cells. This is called the differential blood count.

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Types of white blood cells

The white blood cells can be divided into different types:

They come most often Neutrophil granulocytes before that about 40-60% of leukocytes should make up.
Like all granulocytes, neutrophils are one of them unspecific immune defense. They are the most important cells when it comes to destroying pathogens that have penetrated from the outside.
They do this with the help of a process called Phagocytosis calls: they practically "eat" the bacteria, viruses or fungi.
In terms of quantity are in second place with 20-40% the Lymphocytes, the important part of the specific defense that you can look back on in B and T lymphocytes differs.
- The B lymphocytes develop into so-called after a certain stimulus Plasma cells further whose function is to antibody which can then specifically bind to special structures, whereby these are either destroyed directly or are at least marked so that other cells recognize them as foreign and can pull them to work against them.
- Both T lymphocytes there are again various subgroups. The main ones are: (1) the T helper cells, which coordinate the immune reaction of the body through the release of various messenger substances by enabling "communication" between the individual components of the immune system and (2) the T killer cellsthat are able to directly kill tumor cells or somatic cells that have been infected by viruses.

Next come with about 8% the Monocytesthat are also capable of phagocytosis.
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Finally there is still very little Eosinophilsthat are mainly the defense of Parasites, especially worms, serve, and
Basophil granulocyteswho play an important role in allergic reactions and Inflammation play.

Conditions related to white blood cells

Since white blood cells are essential for our body to protect against external influences (bacteria, viruses, fungi, parasites) and internal (formation of tumor cells, bacteria from our own flora that are potentially disease-causing), it goes without saying that a dysfunction or a lack of white blood cells can prove to be very dangerous and even life-threatening for us.
Important clinical pictures in connection with leukocytes are:

Leukemia: here the number of leukocytes is increased in most cases, but the cells are functionless. In addition, they also displace the remaining blood, which is why there are also deficiency symptoms of red blood cells (anemia) and platelets.
HIV: a virus that attacks the T-helper cells, whereby sooner or later the entire immune system breaks down and a person affected usually falls ill or even dies from an actually relatively banal infection because the body can no longer respond appropriately to it.
Autoimmune diseases: clinical pictures in which the white blood cells are no longer able to distinguish foreign cells from the body's own cells for a mostly unknown reason and therefore the defense is directed against certain necessary body cells, important examples are systemic lupus erythematosus, Crohn's disease, ulcerative colitis , Basedow's disease and many more.

Read more on the topic: What is an autoimmune disease?

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