Spleen function

Dr. Manuela Mai studied medicine at the Universities of Heidelberg and Mannheim. After graduating, she gained clinical experience in gynecology, pathology and clinical pharmacology. She is particularly interested in the broader connections that lead to diseases - also outside of conventional medicine. She completed additional training in classical homeopathy as well as ear and skull acupuncture.

More about the experts All content is checked by medical journalists.

The spleen function consists among other things in the immune defense and blood purification. Despite these important tasks, the spleen is not one of the vital organs. If it has to be surgically removed, other body organs can partially take over their tasks. Find out more about spleen function here!

What does the spleen do?

Although the spleen is not a vital organ, it fulfills important functions. The spleen function includes the following tasks:

Immune functions

The spleen function plays an important role for the immune system: The small organ is involved in the formation, maturation and storage of lymphocytes - a subgroup of white blood cells that is important for the defense against pathogens. In addition, the spleen produces further defense soldiers with the macrophages (phagocytes).

The so-called T lymphocytes are deposited together with dendritic cells as periarterial lymph sheaths (PALS) around fine arterial vessels (arterioles) in the spleen. B lymphocytes are arranged as lymphatic follicles on the PALS. PALS and lymphatic follicles make up the white pulp in the spleen.

The dendritic cells monitor the blood flowing through the spleen. If they find antigens (like particles of pathogens) in it, they pick them up and present them on their cell surface. These antigen presenting cells activate the T lymphocytes, which in turn activate the B lymphocytes.

The activated B-lymphocytes multiply strongly (proliferation) and transform into plasma cells. These produce and secrete suitable antibodies against the antigen discovered in the blood. By attaching to the antigen, the antibodies mark it. Then it can be phagocytosed (“eaten”) by macrophages, for example.

Blood purification and moulting

The red pulp is responsible for this spleen function. The task of this tissue is to identify and break down overaged blood cells (especially red blood cells = erythrocytes).
The red pulp gets its color from the red blood cells (erythrocytes), which are broken down in the wide, venous sinus.

Red blood cells (erythrocytes) circulate in the blood for about 120 days. In the process, they are regularly subjected to a purifying moulting of the blood in the spleen: old and non-functional erythrocytes are removed from the blood and broken down into fragments.

These fragments are then broken down by so-called macrophages (phagocytes) in the sinus spaces of the spleen. The same thing happens in the liver and bone marrow.

In addition, the spleen macrophages are able to filter out, destroy and dispose of other elements such as blood platelets (thrombocytes), tiny blood clots, bacteria and tumor cells from the blood.

Blood storage

Another spleen function is to keep a constant supply of important blood cells (lymphocytes, erythrocytes, thrombocytes) ready for use when needed. This amount of blood is fed into the circulatory system if there is a bleeding in the body or during great physical exertion.

Due to the lack of smooth muscles, the human spleen is unable to contract quickly and thus quickly press a large amount of blood into the circulation. This spleen function is only found in other living things, for example dogs, cats and horses.

Blood formation

Another spleen function is participation in blood formation (hematopoiesis) during prenatal development, i.e. in the unborn. During the fetal phase, blood is formed in the spleen. This spleen function ceases after birth.

Can you live without a spleen?

As important as the spleen function is, it is not essential to life, especially not in adulthood.The function of the spleen is partially taken over by other body organs if the organ has to be surgically removed (splenectomy).

The immunological function of the spleen is taken over by the other lymphatic organs. These are the thymus, bone marrow, lymph nodes and Peyer's plaques of the small intestine.

If necessary, the spleen’s task of cleaning the blood and breaking down blood cells is completely transferred to the red bone marrow and the liver. Even if the spleen is present, these will partly take care of it.

However, spleen removal can have one disadvantage: those affected are often more susceptible to infections and blood poisoning (sepsis). After a splenectomy, the lack of spleen function leads to severe sepsis (massive spread of bacterial pathogens via the blood) in one to three percent of patients.

Tags:  organ systems gpp skin