How come human beings have appendixes if they don’t need really them?
How come human beings have appendixes if they don’t need really them? asks Kayla Winchester, a student in Manhasset, NY.
The appendix. Can’t live with it, can’t live without it.
Oh, wait.
Actually, the appendix is one of the body’s most unobtrusive organs. No painful protests, like the ungrateful stomach after Thanksgiving dinner. No gasping after a sprint to the finish line, courtesy of the overworked lungs. And no ominous rumbling, like intestines encountering the wrong restaurant tomato. And not only can we live nicely with an appendix, we can also live happily without one, if need be.
Did nature simply get sloppy and produce a worm-like cave on the large intestine? Recently, researchers at Duke University in North Carolina unveiled a new explanation for the appendix’s existence. Hint: Rather like the fire extinguisher that usually sits unused on the wall, this tiny organ may be good in a crisis.
The 2- to 4-inch-long appendix juts from the right side of the large intestine like the tail on a dog. Only about a third of an inch in diameter, the narrow appendix has an opening nearly as small as the tip of a mechanical pencil. The one-way door at the exit is called Gerlach’s valve. Mucus made in the appendix flows through this valve and into the bowel.
Trouble starts when something – such as a bit of dried feces — blocks the opening. The result can be infection and inflammation, along with pain, vomiting, and fever. The appendix can swell and even burst, causing a deadly infection called peritonitis. Fortunately, appendicitis is usually easily treated. The infected organ is removed, and antibiotics stop infection from spreading.
When the ailing appendix is removed, the digestive system seems to function just as well without it. So what’s it for? Researchers had suggested that the appendix is part of the immune system, fighting infections by secreting antibodies into the intestines.
The Duke researchers also think that the appendix is a part of the body’s defenses. But its main role, they say, may be as a sanctuary for helpful bacteria, a place where friendly organisms can hang out until they’re urgently needed.
The intestines run on “good” bacteria, colonies which break down food and occupy space desired by not-so-friendly microorganisms. But when we come down with a serious intestinal disease involving diarrhea, the supply of good bacteria quickly dwindles. The researchers note that diarrheal diseases like cholera and dysentery still plague much of the underdeveloped world, and were common throughout human history.
The human appendix sits in a relatively protected place, away from infections raging in the rest of the gut, near the immune system’s lymph glands. Inside this “safe house,” in the mucus behind the one-way door, helpful bacteria can grow and multiply. When diarrhea has run its course, the intestines are denuded of bacteria both good and bad. The appendix can then “re-inoculate” the colon with a ready-made colony. Since people in the developed world are less likely to suffer from diseases like dysentery, the appendix can be removed without apparent harm.
