Aimless appendix?

Krysta Levac
23 January 2012

Scheme of digestive tract, with vermiform appendix marked.

Scheme of digestive tract, with vermiform appendix marked. Olek Remesz (wiki-pl: Orem, commons: Orem)

You probably haven’t thought about your appendix much, unless it’s landed you in the hospital for emergency surgery. But what exactly is your appendix, and is it really as useless as most people believe?

What is the appendix?

Your appendix is located near the junction of your small and large intestines. It’s a closed-ended tube, averaging about 10 cm long, with a small opening into the cecum — a small pouch at the beginning of the large intestine that receives waste from the small intestine. The inside of your appendix is lined with lots of bacteria. This may sound like a bad thing but, in fact, your entire intestinal tract houses billions of bacteria that are indispensible for digestion.

Fast Fact: The full name of the appendix is “vermiform appendix”. Vermiform means “worm-shaped”, which is what your appendix looks like.

The human appendix is often considered a vestigial organ, meaning a useless remnant of an organ that did have a purpose at one time in our evolutionary history. The idea is that our ancestors needed their appendix to help digest fibrous food such as leaves and tree bark. As our diets became more digestible, the appendix lost its function. Recent research suggests that although our appendix is not needed, it still serves a real purpose as a “hideout” for good bacteria. When infections like cholera cause severe diarrhea, bacteria are flushed from the intestines. After the infection is cleared, it is thought that the good bacteria from the appendix then move in and help repopulate the intestinal tract.

However, if the appendix opening becomes blocked (e.g. by fecal material), these bacteria overgrow and the appendix becomes inflamed and painful — a condition called appendicitis. Appendicitis is a medical emergency necessitating removal of the inflamed appendix, which is called an appendectomy.

Fast Fact: Nearly 10 per cent of people need an appendectomy in their lifetime. People between the ages of 10 and 30 are most likely to develop appendicitis.

Most appendectomies are laparoscopic surgery, which uses a few small incisions in the abdomen (with the aid of a thin tube and fiberoptic camera) instead of one big incision.

Fast Fact: Some surgeons have removed the appendix through the mouth … no scars, but definitely not universally appealing.

Untreated appendicitis can be fatal because the inflamed appendix bursts, spilling pus (dead bacteria and white blood cells) into the abdominal cavity, causing further infection (peritonitis). This is a lot of potential trouble from an organ that doesn’t have an obvious function!

Learn More!

An overview of the appendix andappendicitis

Medical information aboutappendicitis

A short article about theappendix being a hideout for good bacteria

An interesting audio clip (10minutes) about the role of the appendix (scroll down to the clip titled “TheLast Word on the Appendix”)

A CurioCity article about theimportance of bacteria in our digestive tract


Article first published January 24, 2011.

Photo Credit: iStock

Krysta Levac

After an undergraduate degree at the University of Guelph, I earned a PhD in nutritional biochemistry from Cornell University in 2001. I spent 7 years as a post-doctoral fellow and research associate in stem cell biology at Robarts Research Institute at Western University in London, ON. I currently enjoy science writing, Let's Talk Science outreach, and volunteering at my son's school. I love sharing my passion for science with others, especially children and youth. I am also a bookworm, a yogi, a quilter, a Lego builder and an occasional "ninja spy" with my son.

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