Function
- Similar in structure to a large lymph node
- Acts primarily as a blood filter.
- Removes old red blood cells and holds a reserve of blood, which can be valuable in case of hemorrhagic shock
- recycles iron
- as a part of the mononuclear phagocyte system, it metabolizes haemoglobin removed from senescent red blood cells (erythrocytes).
- synthesizes antibodies in its white pulp and removes antibody-coated bacteria and antibody-coated blood cells by way of blood and lymph node circulation.
Structure
The spleen contains two main regions of tissue called white pulp and red pulp.
- Red pulp: Contains venous sinuses (cavities filled with blood), and splenic cords (connective tissues containing red blood cells and white blood cells).
- White pulp: Mostly consists of immune cells (T cells and B cells).
Pathology
- Enlarged Spleen (Splenomegaly): caused by eg viral mononucleosis (“mono”), liver disease, blood cancers (lymphoma and leukemia), etc
- Ruptured spleen: can cause life-threatening internal bleeding
- Sickle cell disease: inherited anaemia, abnormal red blood cells block the flow of blood through vessels and can lead to organ damage, including damage to the spleen.
- Thrombocytopenia (low platelet count): enlarged spleen sometimes stores excessive numbers of the body’s platelets.
- Accessory spleen: About 10% of people have a small extra spleen. This causes no problems and is considered normal.
It is possible to live without a spleen, but the individual will be more susceptible to various pathologies including infection.
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