What Does the Spleen Do? (3 Functions)

What Does the Spleen Do? (3 Functions)

The spleen is a highly specialised organ that acts as the “quality control” center for your blood. Located in the upper left quadrant of the abdomen, tucked behind the ribcage and near the stomach, it is roughly the size of a clenched fist.

While you can live without it, the spleen plays a critical role in keeping your blood clean and your immune system ready for action.

3 Primary Functions of the Spleen

1. The Blood Filter (Hematological Quality Control)

The spleen is the body’s primary filter for blood. As blood flows through it, the spleen identifies and removes:

• Old Red Blood Cells: Red blood cells live for about 120 days. Once they become “worn out” or damaged, the spleen breaks them down.

• Foreign Invaders: It traps bacteria, viruses, and other debris, preventing them from circulating further.

• Recycling: It salvages useful components, like iron, from old red cells and returns them to the bone marrow to make new blood.

2. The Blood Reservoir (Emergency Storage)

The spleen acts as a biological “savings account” for blood.

• Reserve Supply: It stores a significant volume of red blood cells and platelets.

• Emergency Release: In the event of a severe injury or sudden blood loss, the spleen can contract, squeezing this reserve into the bloodstream to help maintain blood pressure and oxygen delivery.

3. Antibody Production (Immune Defence)

The spleen is a major organ of the immune system.

• Identifying Threats: It produces specialized proteins called antibodies.

• Neutralising Invaders: These antibodies tag bacteria and viruses so that white blood cells can find and destroy them. This is particularly important for fighting encapsulated bacteria like those that cause pneumonia and meningitis.

Anatomy: Red Pulp vs. White Pulp

The spleen is made up of two distinct types of tissue, each with a different job:

• Red Pulp: Filled with blood vessels, this area is responsible for the “filtering” and storage of red blood cells.

• White Pulp: This is lymphoid tissue. It is packed with white blood cells (lymphocytes) and is responsible for the “immune” functions, such as producing antibodies.

Splenomegaly: Why Does the Spleen Enlarge?

An enlarged spleen is called splenomegaly. You usually cannot feel a healthy spleen, but if it swells to 2–3 times its normal size, a doctor can feel it during an exam. Common causes include:

• Infections: Such as Mononucleosis (Mono), Malaria, or Syphilis.

• Blood Cancers: Including Leukemia and Hodgkin’s Lymphoma.

• Liver Disease: Cirrhosis can cause pressure to back up into the spleen.

• Anemias: Conditions like Sickle Cell Disease where the spleen works overtime to filter abnormally shaped cells.

Splenectomy: Living Without a Spleen

A splenectomy is the surgical removal of the spleen. This is usually done via Laparoscopy (keyhole surgery) to ensure faster recovery.

Can you survive without a spleen?

Yes. However, because the spleen is so important for immunity, life without it requires precautions:

• The Liver Takes Over: The liver assumes many of the spleen’s blood-filtering duties.

• Infection Risk: You become more “immuno-compromised.” Patients without a spleen are at a lifelong higher risk for overwhelming infections.

Vital Precautions for Post-Splenectomy Patients:

1. Vaccinations: Stay up-to-date on shots for pneumonia, meningitis, and the flu.

2. Antibiotics: Some patients require daily low-dose antibiotics.

3. Medical ID: Wear a medical alert bracelet (like MedicAlert) to inform emergency responders that you lack a spleen.

Summary Table: Spleen Facts at a Glance