The tasks of the leukocytes as an important component of the blood. Because of their white color under the microscope, they are also called white blood cells.
Leukocytes are formed in the bone marrow of the breastbone and pelvis, and in children also in the bones of the arms and legs.
Roles of the white blood cells in the human body
White blood cells come in different types with specific tasks to fulfill – in particular granulocytes and lymphocytes. A healthy, middle-aged person has between 4,000 and 10,000 leukocytes per microliter of blood. In children, the value is often increased to 15,000.
In infections, the number of leukocytes increases to up to 30,000. Values above this point to a disease of the bone marrow ( leukaemia ). The leukocytes have a lifespan of between a few days and a few months.
Types and functions of leukocytes
The main task of the white blood cells is to defend against foreign bodies. These include viruses, bacteria and tumor cells as well as fungi and worms. The neutrophilic granulocytes take over the elimination of pathogens and serve the non-specific defense.
In addition, they leave the bloodstream and migrate into the surrounding tissue. The eosinophilic granulocytes defend against allergic diseases and infestation with parasites . In contrast, the basophilic granulocytes play a major role in the memory-immune response. Monocytes eliminate tissue debris and microbes, which is why they are known as scavenger cells .
In contrast, the lymphocytes are significantly involved in the formation of specific antibodies. They target a specific pathogen. Compared to granulocytes , they occur in smaller numbers in the blood. Elevated levels indicate a viral or bacterial infection, as well as various types of cancer . After treatment with cortisone and cytostatics or radiotherapy, the proportion of lymphocytes is often reduced.
leukocyte lifespan
Interesting information about the lifespan of leukocytes
The lifespan of leukocytes depends first of all on the type of leukocytes. Here, the monocytes, the granulocytes and the lymphocytes differ. After their production in the bone marrow, the monocytes live for one to three days before they differentiate. Then they migrate into the tissue. The granulocytes are again subdivided into basophilic and neutrophilic cells . While the former exist in the bloodstream for up to seven days, the second group begins to break down one to four days after production. The lifespan of lymphocytes is between several weeks and a few years.
Doctors differentiate between T cells, B cells and NK cells. When patients suffer from bone marrow disease, weak white blood cells form. Due to mutations or immaturity, their lifespan decreases.
How long have white blood cells existed?
On average, the age of leukocytes ranges from several days to several weeks. The “older” cells have the ability to actively leave the blood. Due to their amoeboid form, they migrate into the tissue to perform their tasks in the target organs. The life span of the leukocytes mainly depends on their “consumption” in the body.
Due to an infection or a disease, the human organism needs more white blood cells to fight the pathogen. In this case, the cells produce and break down faster. Diseases that directly affect the immune system, such as leukemia, also affect the lifespan of leukocytes.
Where and when does the breakdown of leukocytes take place?
The formation of white blood cells takes place in the red bone marrow, for example. These include:
- Ribs,
- the sternum,
- the skull
- and the vertebral bodies.
Furthermore, there is tissue in your body that exclusively produces the leukocytes. The focus is on the lymphatic tissue, which includes the following areas:
- lymph nodes,
- Spleen,
- Tonsillen
- and corresponding tissue in the intestine.
The antibodies usually do their job outside of the bloodstream, so that they are distributed throughout the organism. For this reason, they only remain in the blood for a few hours. When they leave the bloodstream, they are not necessarily broken down. In particular, the leukocytes with a long life expectancy survive in the remaining tissue without difficulty. The degradation process begins at the site of their function as soon as the white blood cells no longer carry out their work reliably.
In this case, healthy leukocytes protect the body by initiating phagocytosis . Here, the white blood cells take up leukocytes with, for example, abnormalities in the cell nucleus and utilize them. There is also the possibility that the life span of the leukocytes decreases due to an autoimmune disease. The killer cells see the body’s own antibodies as foreign substances and destroy them. If you suffer from the phenomenon, your immune system is weakened, increasing the risk of infection.
How long do monocytes stay in the body?
The monocytes belong to the cells that have the ability to phagocytosis . After their formation in the lymphatic tissue, they remain in the human organism for up to 64 days. This is followed by the transformation into macrophages, known as scavenger cells. The average lifespan of these cells is several weeks. In form, they track down foreign bodies and vermin within the body, absorb them and thus exterminate them.
If the monocytes are broken down excessively, you suffer from monocytopenia. Complications in the lymphatic tissue may be the cause. If the leukocytes have a short lifespan, the likelihood of foreign pathogens penetrating and triggering infections, for example, increases. Therefore, timely treatment of the health complications is given priority.
Granulocytes – the special leukocytes and their lifespan
The granulocytes are also among the scavenger cells, as they actively identify and destroy bacteria, viruses and fungi. Doctors distinguish between eosinophilic, neutrophilic and basophilic granulocytes. The latter have a lifetime of up to seven days. The neutrophil cells can already be broken down after 24 hours. They usually reach a maximum life span of four days. In order to break down the special antibodies, they enter the mononuclear phagocyte system. The monocytes absorb the elements, so that a slow decomposition begins.
The residence time of the lymphocytes in the body
The life span of these leukocytes is between several weeks and years. Here, too, the division into different categories plays an important role. For example, B lymphocytes perform cell division, resulting in memory cells and plasma cells . The latter live only a few weeks before they are broken down in the body tissue. The situation is different with the memory cells. Your task is to memorize the structure and appearance of dangerous pathogens.
If these enter your body, the special lymphocytes pass on the information to the scavenger cells. In this way, you benefit from the timely destruction of the foreign bodies. As a rule, the cells remain in the organism for several years, although lifelong existence is also possible.
Reduced lifespan in leukemia
Leukemia is a cancer in which damage to the bone marrow leads to impaired cell production. The white blood cells that enter the bloodstream immature or in a mutated form are particularly affected. Without treatment of the disease, patients die within a short time.
This is due to the fact that the changed leukocytes have a lifespan of eight to twelve days. In this case, the period of time affects all white blood cells, so that the organism dies without new production.
Important tips for patients
If you are interested in the lifespan of leukocytes, consult your family doctor, for example. You ask him to do a differential blood count so he can see the number of each type of leukocyte. If the concentration of the antibodies is below the respective standard values, there is a suspicion of faulty production. It also happens that the human body eliminates the cells prematurely. The doctor also diagnoses this process on the basis of the complete blood count and, if necessary, a blood sample.
If you suffer from leukemia, the cause is genetic changes in the immature progenitor cells. Their lifespan is well below the normal residence time of white blood cells. The factors that trigger the disease also include psychological components.
The study comes to the conclusion: “Psychogenic carcinogenesis: Carcinogenesis is without exogenic carcinogens”. OV Bukhtoyarov and DM Samarin published it in October 2009.
http://www.medical-hypotheses.com/article/S0306-9877(09)00418-6/abstract
https://www.uk-halle.de/fileadmin/Bereichsordner/Institute/AnatomieUndZellbiologie/Lehre/newBlut.pdf
Leukocytes – the “guards” in the organism
One of the most important tasks of the leukocytes is to systematically search the body for pathogens and injuries, including their elimination. Their targets are cancer cells, as well as inflammation and injury. To do this, they move in the blood vessels and tissue and search the cell walls for suspicious structures. When they encounter an antigen, the plasma cells start producing antibodies. These attach themselves to the pathogen in order to mark it as a foreign body. They then remove the intruder from the body.
A properly functioning immune system requires the presence of leukocytes. In the case of a viral or bacterial disease, the doctor will examine the patient’s blood. Based on the number of leukocytes, together with other results, he receives important information for a diagnosis. If the number is too low, the immune system becomes weak and the patient is more susceptible to diseases caused by infection.
In addition, some medications and radiation therapy lower the value of leukocytes. If the value is too high, the leukocytes fight massively against the pathogen. Stress is often behind it and there are no other signs of illness. A greatly increased value directs the suspicion of leukemia, in which the proliferation of white blood cells gets out of control. Its symptoms are diverse and range from tiredness and paleness to an increased tendency to bleed.
Conventional medicine today knows suitable methods for treating leukemia and other cancers. The tasks of the leukocytes thus include protecting the body from foreign bodies of all kinds by building an immune system.
