20% of Humans Have an Extra Spleen—Here's Why

TL;DR

Some individuals can be born with or develop additional spleens, known as accessory spleens or splenosis, which have similar functions but are smaller in size.

Transcript

This SciShow video is supported by LMNT. Head to D-R-I-N-K-L-M-N-T dot com/scishow for a free sample pack of electrolyte drinks with any order. [♪ INTRO] We generally know that there are organs in the human body that we can quite literally live without. Your appendix, your gallbladder, your spleen… these organs are kind of optional. But there’s a ... Read More

Key Insights

• 🖐️ The spleen, although not vital, plays a role in the immune system and filtering blood.
• ❓ Extra spleens, such as accessory spleens and splenosis, are relatively common and usually benign.
• ❓ Accessory spleens can provide some residual function after spleen removal.
• 💗 The ability of the spleen to regenerate and grow additional spleens is still not fully understood.
• ❓ Understanding spleen regeneration may have implications for regenerating other organs.
• ❤️‍🩹 Extra spleens are typically harmless, but complications can arise if they end up in the wrong locations.
• 🚚 The liver, another organ involved in blood filtration, also has the ability to regenerate.

Questions & Answers

Q: How common is it to have an accessory spleen?

Roughly 10-30% of people are born with accessory spleens, and about 26% of those individuals have more than one.

Q: What function do accessory spleens serve?

Accessory spleens are smaller versions of the spleen and provide residual function. They can help filter blood and support immune responses, though they are not as effective as a full-sized spleen.

Q: Are extra spleens a cause for concern?

In most cases, extra spleens are benign and do not cause problems. However, if an unknown lump appears on a scan, doctors may need to rule out cancer or other complications.

Q: Why can the spleen regenerate and grow additional spleens?

The exact mechanism behind spleen regeneration is still not fully understood. Recent research has identified stromal cells that may play a role in tissue regeneration, but the reasons why the spleen has this ability remain mysterious.

Summary & Key Takeaways

• The spleen is a non-vital organ that plays a role in the immune system and blood filtration.

• It can be safely removed if damaged, but without a spleen, individuals are more susceptible to infections and illnesses.

• Some people are born with extra spleens (accessory spleens), and others can develop additional spleens (splenosis) following injuries to the primary spleen.