You probably know someone who's had to have their appendix out. But do you happen to know what appendicitis actually is? Or what your appendix does, for that matter?

The Daily Show wasn’t quite “daily” this week after the show's new host Trevor Noah was sidelined by an emergency appendectomy Wednesday morning. Thankfully, Noah’s surgery was complication-free, and the show will go on tonight night as usual (so expect an opening monologue filled with jokes about hospital gowns).

Chances are, Trevor Noah's appendectomy is not the first you've heard of. You probably have a friend who's had to have their appendix out, but do you happen to know what appendicitis actually is? Or what your appendix does, for that matter?

Yeah, we thought so. Here are some things to know about this seemingly unnecessary organ and why it seems to cause so much trouble.

The basics

Appendicitis is simply an inflammation of the appendix, a thin, worm-shaped pouch attached to the large intestine. Telltale symptoms include belly-button pain and right-side abdominal pain. But while the movies make it seem like the symptoms are excruciating and therefore obvious, it’s actually often the opposite, as many people don’t feel the pain in the same place, depending on where their appendix sits.

Some people have an appendix that points backward instead of forward in the body, so the symptoms present in a different location, Eugene Shapiro, MD, deputy director of the Investigative Medicine Program at Yale University previously explained to Health, making the diagnosis even harder.

Other symptoms include fever, nausea and vomiting, and bloating. If you have any of these, the best advice is to see your doctor ASAP.

Pain that stops isn’t always a good thing

Sometimes people do have the telltale pain, but then the appendix ruptures and the pain is relieved so they think they're fine, Dr. Shapiro adds. When it ruptures, fluids can seep into the abdomen and cause an infection called peritonitis, which can be life-threatening. A ruptured appendix requires immediate surgery to remove the tissue and clean the abdominal cavity to prevent that.

Lesson: if you experience symptoms at all, you should see your doctor whether you start to feel better or not.

Appendicitis tends to skew young

People between the ages of 10 and 30 are the most common sufferers. But it may be becoming more common in older people. According to a 2012 study in the Journal of Surgical Research, the annual rate of appendicitis in all Americans went up from 7.62 cases for every 10,000 people, to 9.38 between 1993 and 2008. And for those between 30 and 69-years-old, the number of cases increased by 6.3%. The researchers found it was more common in men.

Surprise! The appendix is actually useful

For years, doctors weren’t sure if the appendix had any real purpose. They thought perhaps it was a piece of the intestine that was leftover from earlier stages in the course of our evolution. But researchers are now finding that it might have some use.

In a 2007 study in the Journal of Theroetical Biology, researchers proposed that the appendix is a “safe house” for friendly micro-organisms, meaning it's a place where these bacteria can grow and hang out. Then, if needed, they can re-populate the colon "in the event that the contents of the intestinal tract are purged following exposure to a pathogen." In other words, if an illness causes a big die-off in your gut, your appendix might be able to help get your flora growing again.

You might not need surgery

While surgery has long been the main treatment for appendicitis, a recent study from the Journal of the American Medical Association suggests that antibiotics might be able to save most sufferers from going under the knife.

How? Turns out there are actually two types of appendicitis: one that's more serious and always requires surgery, and a milder form that can be treated with antibiotics. This milder form is much more common, making up about 80 percent of cases, the researchers estimated. A CT scan can reveal which type you have, allowing doctors to make the call.

So, if you come down with a sharp pain in the belly button, fret not, you may get to keep your appendix after all. Here's hoping Trevor Noah does fine without his.