Spleen
This
article gives a brief overview of the spleen and its functions.
The spleen is an organ about the size of a clenched fist found on
the left-hand side of your upper abdomen. Its main functions are to filter your
blood, create new blood cells and store platelets. It is also a key part of
your body's immune system.
Where is the spleen
found?
The spleen is found on the left side of your body, behind the
stomach on a level with the 9th to 11th ribs. It is similar in structure to a
lymph node, and is the largest lymphatic organ in the body. The spleen contains
two main types of tissue, white pulp and red pulp. White pulp is lymphatic
tissue (material which is part of the immune system) mainly made up of white
blood cells. Red pulp is made up of venous sinuses (blood filled cavities) and
splenic cords. Splenic cords are special tissues which contain different types
of red and white blood cells.
What does the
spleen do?
Blood flows into the spleen where it enters the white pulp. Here
white blood cells called B and T cells screen the blood flowing through. T
cells help to recognise invading pathogens (germs, for example bacteria and
viruses) that might cause illness and then attack them. B cells make antibodies
that help to stop infections from taking hold.
Blood also enters red pulp. Red pulp has three main functions.
Blood also enters red pulp. Red pulp has three main functions.
- It removes old and damaged red blood
cells. Red blood cells have a lifespan of about 120 days. After this time
they stop carrying oxygen effectively. Special cells called macrophages
break down these old red blood cells. Haemoglobin (a chemical which
carries oxygen) found within the cells is also broken down and then
recycled.
- Red pulp also stores up to one third
of the body's supply of platelets. Platelets are fragments of cells that
circulate in the bloodstream that help to stop bleeding when we cut
ourselves. These extra stored platelets can be released from the spleen if
severe bleeding occurs.
- In
foetuses (unborn babies) red pulp can also act like bone marrow, producing
new red blood cells. Usually this stops after birth, but may start again
in some people with certain diseases.
While the spleen performs a number of important functions it is
not essential to life. Other organs such as the liver and bone marrow are able
to take over many of its jobs. Your spleen may be removed (splenectomy) for
various reasons. For example, because of an illness that affects the spleen, or
if it is damaged by an injury. Also, the spleen may not work well in some
diseases. For example, sickle cell disease, thalassaemia, and lymphomas.
However, people who have had their spleen removed are more likely to get infections and may be put on long-term antibiotics to prevent this.
However, people who have had their spleen removed are more likely to get infections and may be put on long-term antibiotics to prevent this.
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