Spleen: red blood cell store
In the splenic tissue, the capillaries are permeable to blood, including red blood cells, and blood oozes from the walls of the capillaries into the joint horizontal links, forming the red splenic tissue.
The figure shows that the spleen is divided into two parts for blood storage: the venous sinuses and the tissue part. The sinuses can swell like other parts of the venous system to store all the blood.
In the splenic tissue, the capillaries are permeable to blood, including red blood cells, and blood oozes from the walls of the capillaries into the joint horizontal links, forming the red splenic tissue. Red blood cells are in these links, while plasma fluid flows in the venous sinuses and into the general circulatory system. Consequently, the splenic tissue acts as a special storehouse that can store many red blood cells, concentrated red blood cells, and can be secreted into the general circulation when stimulated by the sympathetic nervous system. The spleen and its venous system constrict. Up to 50 ml of immature red blood cells can be released into the circulation increasing the haematocrit by 1-2%.
In other parts of the spleen tissue is likened to the island of white blood cells, where white blood cells are concentrated and is called "white tissue". Here, the lymphocytes act in tandem with the lymph nodes. They are part of the body's immune system.
Figure: Functional structure of the spleen
The function of cleaning blood, eliminating old cells of the spleen
Blood cells that pass through the spleen tissue before entering the venous system must undergo compression. Therefore, fragile red blood cells will not tolerate trauma. For that reason, a lot of red blood cells destroyed in the body are destroyed in the spleen. After the cells burst, haemoglobin is released, and the dead cells are eaten by the macrophages in the spleen, and the process of digesting the food absorbs nutrients to create new cells.
Reticular cells of the spleen
The spleen tissue is composed of numerous macrophages, and the venous sinus system is associated with similar cells. These cells have a blood-cleansing function, working in concert with a similar phagocytic system in the hepatic sinusoids. When the blood is infiltrated by pathological factors, the splenic phagocytocytes will quickly remove debris, bacteria, parasites, etc. Likewise, in chronic diseases, the spleen will enlarge. like lymph nodes enlarge and work with quick cleaning function.