Lymphatic system
Spleen
The spleen is a fist-sized organ on the left side of the abdomen that filters the blood and helps fight infection. You can live without it, but you become more prone to certain infections.
What it is
The spleen is a soft, purplish organ that is part of the lymphatic (immune) system, sitting under the left ribs.
Where it is
The upper left abdomen, under the ribs, near the stomach.
What it does
Filters the blood — removing old or damaged red cells — stores some blood cells, and helps the immune system fight certain infections.
How it works
Blood passes slowly through the spleen, where worn-out red blood cells are broken down and recycled and immune cells screen for germs. It also acts as a reservoir of blood and immune cells.
When things go wrong
Common conditions affecting the spleen
- Enlarged spleen (from infections or blood conditions)
- Splenic rupture (from injury — a surgical emergency)
- Increased infection risk after spleen removal
Education and reference only. This explains the anatomy in plain terms and is not a diagnosis. Sudden severe symptoms — such as severe chest pain, breathlessness or collapse — are an emergency; call 999.
Looking after it
Keeping your spleen healthy
People without a working spleen need specific vaccinations and sometimes preventive antibiotics, and should seek prompt care for fevers.
Did you know?
An interesting fact
You can live without a spleen — other organs take over its jobs — but you become more vulnerable to certain infections and need extra protection.
Answers
Spleen: frequently asked questions
What does the spleen do?
The spleen filters the blood, recycles old red blood cells, and helps the immune system fight certain infections.
Can you live without a spleen?
Yes. Other organs take over its functions, but you become more prone to certain serious infections, so vaccinations and prompt treatment of fevers are important.
Sources
Where this is drawn from
- NHS — Anatomy and body systems
- Gray's Anatomy for Students
- TeachMeAnatomy / TeachMePhysiology
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