What Is The Purpose Of A Spleen? The Basics

The spleen is a small organ tucked under your rib cage on the left side of your body. It is about the size of your fist and sits near your stomach. Its main jobs are filtering your blood and helping your immune system fight infections. Unlike your heart or lungs, you can live without a spleen, but your body has to work harder to stay protected.

What Is The Purpose Of A Spleen?

The spleen has three main jobs. It filters old or damaged red blood cells out of your bloodstream. It helps your body fight certain infections by producing white blood cells. And it stores platelets and white blood cells, releasing them when your body needs them.

Think of it as a quality control station for your blood. Blood flows through the spleen, and the organ checks each red blood cell. Healthy cells pass through. Old, stiff, or damaged cells get broken down. The spleen recycles the useful parts, like iron, and sends them back into your body.

This filtering work is constant. Every drop of your blood passes through the spleen many times a day. It is a quiet worker that rarely gets attention until something goes wrong.

Where Is The Spleen Located?

Your spleen sits in the upper left part of your abdomen. It is protected by your lower ribs. It sits just below your diaphragm and behind your stomach. On a typical adult, it is roughly 4 to 5 inches long, but size varies from person to person.

You cannot feel a healthy spleen. It is hidden behind your rib cage. If you can feel it through the skin, that is usually a sign of swelling, which doctors call splenomegaly. That condition needs medical evaluation.

Because it sits close to your stomach, an enlarged spleen can press on nearby organs. Some people feel full after eating very little because the swollen spleen pushes against the stomach.

How Does The Spleen Filter Blood?

The spleen is filled with two types of tissue: red pulp and white pulp. Each does a different job.

Red pulp makes up most of the organ. This is where old red blood cells are destroyed. Red blood cells live about 120 days. After that, they become less flexible and can no longer squeeze through tiny blood vessels. The red pulp catches these aging cells and breaks them down.

The spleen also removes abnormal red blood cells. In conditions like sickle cell disease, red blood cells are misshapen and stiff. The spleen traps them and destroys them. This is helpful, but it can also cause problems when the spleen works too hard and destroys healthy cells as well.

White pulp is the immune part of the spleen. It contains white blood cells called lymphocytes. These cells recognize germs and produce antibodies to attack them. When a bacteria or virus enters your bloodstream, the white pulp helps your immune system respond.

How Does The Spleen Support Immunity?

The spleen is a key player in fighting certain types of infections. It is especially important for protecting against bacteria that have a slippery outer coating, like the ones that cause pneumonia and meningitis. These bacteria are hard for the immune system to grab onto, and the spleen has special cells that can trap them.

When you are born, your spleen helps your immune system learn to recognize threats. As you age, other parts of the immune system take on more responsibility. But the spleen never stops contributing.

People without a spleen are at higher risk for serious infections from certain bacteria. This is why doctors recommend specific vaccines for people who have had their spleen removed. The vaccines help the immune system compensate for the missing organ.

What Happens If Your Spleen Is Removed?

Splenectomy is the surgical removal of the spleen. It is done when the spleen ruptures from injury, becomes dangerously enlarged, or when diseases like certain blood disorders require it.

You can live without a spleen. Other organs, especially the liver and bone marrow, take over most of its filtering work. The liver can break down old red blood cells. The bone marrow can increase its production of immune cells.

But protection is not the same. The liver cannot fully replace the spleen’s immune function. People without a spleen have a permanently higher risk of infection from encapsulated bacteria. This risk is highest in the first few years after removal.

Doctors manage this risk with vaccines. If you have no spleen, you should stay up to date on pneumococcal, meningococcal, and Haemophilus influenzae type b vaccines. Some doctors also recommend daily antibiotics for certain high-risk patients. These decisions are made on an individual basis.

If you have your spleen removed, you should tell every doctor and dentist you see. Even a routine dental procedure can introduce bacteria into your bloodstream, and your body needs extra protection. Some people with no spleen carry a medical alert card or wear a bracelet.

What Causes An Enlarged Spleen?

An enlarged spleen is not a disease itself. It is a sign that something else is wrong. Many conditions can cause it.

Infections are a common cause. Mononucleosis, hepatitis, and malaria can all make the spleen swell. The organ enlarges because it is working hard to fight the infection.

Liver disease can also cause splenomegaly. When the liver is damaged, blood flow through it slows down. This increases pressure in the veins that lead to the spleen, causing it to swell.

Blood disorders like sickle cell disease and thalassemia can enlarge the spleen as it works overtime to filter abnormal cells. Some cancers, like leukemia and lymphoma, can also cause the spleen to grow.

Symptoms of an enlarged spleen include pain or fullness in the upper left abdomen, feeling full without eating much, fatigue, and frequent infections. But many people have no symptoms at all. The condition is often discovered during a routine physical exam or imaging test for another reason.

Can You Prevent Spleen Problems?

You cannot prevent most spleen conditions. Many are caused by genetics, infections, or underlying diseases you cannot control. What you can do is reduce your risk of injury to the area.

Car accidents and hard blows to the left side of your abdomen are the most common causes of a ruptured spleen. Wearing a seatbelt in the car is one of the best ways to protect it. Contact sport athletes should follow safety guidelines and wear appropriate protective gear.

If you notice pain in your upper left abdomen that does not go away, or if you feel unusually tired, see a doctor. An enlarged spleen can be detected with a simple physical exam or an imaging test like an ultrasound or CT scan.

If your spleen is enlarged, avoid contact sports and heavy lifting. A swollen spleen is more fragile and can rupture more easily. Your doctor will tell you when it is safe to resume normal activities.

How Do Doctors Check The Spleen?

A doctor can sometimes feel an enlarged spleen during a physical exam. They press gently on your upper left abdomen while you take a deep breath. But a healthy spleen cannot be felt this way, and even an enlarged one can be missed if the exam is difficult.

Imaging tests are more reliable. An ultrasound is often the first test used. It is painless, uses no radiation, and gives a clear picture of the spleen’s size and shape. A CT scan provides even more detail and is used when the spleen may be injured.

Blood tests can also help. A complete blood count measures your red cells, white cells, and platelets. If the spleen is trapping too many of these cells, their numbers in the blood will be low. This can be a clue that the spleen is not working normally.

When Should You See A Doctor?

See a doctor if you have persistent pain in your upper left abdomen. Seek urgent care if the pain comes after an injury, even a minor one. A ruptured spleen is a medical emergency.

Signs of a ruptured spleen include severe abdominal pain, dizziness, confusion, and signs of shock like pale skin and a rapid heartbeat. This is a life-threatening situation. Call emergency services immediately.

For less urgent concerns, mention any unexplained fatigue, frequent infections, or a feeling of fullness after small meals to your doctor. These symptoms can have many causes, but the spleen is one possibility worth checking.