Can you name the least essential, most expendable body parts?

Published on Wednesday, May 1, 2019

By: Gary Pettus, gpettus@umc.edu

Neglected, replaceable and sometimes disposable, certain human organs and other body parts go through life like a pair of old, brown shoes: lonely and unloved.

You might call them the World’s Most Disrespected Body Parts. Which ones should top a list of the lowly?

“My first thought is the appendix,” said Dr. Marianne Conway, assistant professor of neurobiology and anatomical sciences at the University of Mississippi Medical Center and course director for developmental anatomy. “What does it really do?”

Conway was one of four UMMC experts asked to weigh in, and while there was some overlap, each offered distinctive ideas about which body parts sink to the bottom of the barrel, usefulness-wise.

Along with Conway, the contributors were Dr. Yuefeng “Jordan” Lu, assistant professor of neurobiology and anatomical sciences; Dr. Sonya Shipley, assistant professor of family medicine; and Dr. Shamsi Berry, assistant professor of health informatics and information management in the School of Health Related Professions.

The following body parts popped up in the conversation.

Appendix

This tube of treachery, approximately the length of a Quaker Oats Chewy bar, sits (in the normal world) in the lower right abdomen, where it spins its little webs.

“Not only is it useless, it causes grief,” Conway said. “Grief” being defined, at times, as a pus-filled inflammation: appendicitis.

In UMMC’s gross anatomy lab, Conway and Lu are part of a faculty guiding students in the dissection of body donors who often don’t have one, meaning the appendix.

“If it’s taken out, nothing really happens,” Conway said. “You live on.”

On the other hand, if it isn’t taken out, something can really happen. This worm-like structure, in a diseased state, is the source of symptoms that mimic the signposts of other conditions – for instance, the attachment of a fertilized egg in a place other than inside the uterus, known as an ectopic pregnancy.

You don’t have to be a medical student to know that appendicitis and babies are not the same thing, but certainly, a cautious diagnosis is prudent, thanks to the appendix’s duplicity.

On the other hand, this deceitfulness renders the appendix useful – as a teaching tool, Conway said. Through it, students may learn the complex relationship between localized and referred pain (pain felt in a part of the body other than the real source).

And because of its location, at the junction of the small and large intestine, it may serve as a “gatekeeper that prevents bacteria from going back into the small intestines,” Conway said.

“But I’m not sure if anyone has done research on any possible adverse effects caused by losing the appendix,” she said.

Lu is more inclined to give the appendix its anatomical props.

“It’s surrounded by many lymph node cells,” he said. “That gives the body time to produce antibodies to fight infections.”

Berry, who has a Ph.D. in biological anthropology, broke the tie.

“I would give up my appendix,” she said. “We really don’t know what it does.”

Her second choice for the world’s least useful organ brings us to the

Gall Bladder

Although the gall bladder has a purpose, Berry said if it’s confiscated, the liver is programmed to step up.

Its purpose, Lu said, is as a warehouse for bile, the fluid that aids digestion. The liver makes it and the gallbladder takes it – the excess, that is.

“We are not eating continually, so we need somewhere to store the bile that isn’t being used,” Lu said. “However, if the gall bladder is removed, patients can adapt by adjusting their diets, such as eating fewer fats and proteins.”

That’s something to chew on, or not. Which brings us to

Wisdom Teeth . . . and Tonsils . . . and Kidneys, oh my!

“If I had to give something up, it would be wisdom teeth,” Shipley said. “They’re not very useful, for the most part, and they pretty much cause problems if they show up.

“Back in time, they probably served us well when we weren’t eating food that was processed or even cooked. So it was probably useful to have those extra teeth in the back that could grind when our jaws were bigger and more powerful.”

Like many patrons of vigilant dentistry, Conway lost all of her wisdom teeth when she was young.

“And I can still chew,” she said. “So that’s another candidate.”

Where you live may also make a body part more, or less, relevant, and that includes the mini-gherkin-sized tonsils.

“Tonsils play a role in immunity and fighting infections,” Shipley said. “I would think tonsils would be beneficial if you don’t have a well-developed health care system. But you can definitely live without them.”

Lu would rather not.

“The tonsil is like a watchman: It warns us of what’s coming,” such as lung and throat infections. “You have other watchmen, but that doesn’t mean the tonsils aren’t important.”

A person’s diet is also a chief sponsor of a body part’s relative awesomeness, Berry said.

“Certain organs, like the pancreas, may be more important with a high-sugar diet, and the gall bladder with a high-fat diet.”

Let’s not leave out the liver, Lu said.

“If you drink a lot, you want a powerful liver, or if you eat a lot of fat.”

Where you live and work is also an anatomical influencer, Lu said.

“If you’re around pollution, you would want to have more powerful lungs. If you live in the desert, the kidneys are even more important.

“But if you live in Mississippi and have plenty of water, it may not be as necessary to have two functioning kidneys.”

Regional experiences in dining could possibly weaken or strengthen the case for a body part’s reason to live, Berry said – but only if the variations in diets are stark.

“I’m thinking about where I’m from, California, and the differences between northern and southern [parts of the state]. But I would say it wouldn’t affect the organ’s usefulness, but rather that the enzymes which are important in breaking down food would differ.

“Diet was extremely different through the evolution of mankind. As far as I know, we have no proof that any human organs were more important in the past, even ones like the appendix, which we refer to as a vestigial organ.”

To conclude that the relative importance of certain organs diverged through time, our contributors said you would have to go back to the evolving of the Australopithecines, extinct hominids who roamed the earth bereft of things like Jell-O and the George Foreman grill. That’s a few million years ago, before Homo sapiens neanderthalensissold out for GEICO.

“A large amount of protein and fat was needed to help with increasing brain size,” Berry said.

Judging from current events, it didn’t take.

Although our ancestors may have been short on the smarts necessary to flatten today’s cities with a single blow, they certainly weren’t lacking for that which constitutes our next nominee,

Hair

As any moderately gifted fourth-grader knows, it’s an organ. Although it would seem that substituting the word “organ” for “hair” is no way to sell mousse.

“Honestly, I think we can live without hair,” Shipley said. “Once upon a time, we were probably totally covered in hair. So I have no idea why evolution said you would keep a patch of hair only on your head and on other select body parts.”

Eyebrows, among other sensitive areas, come to mind.

“Cosmetically, we’re used to seeing each other with hair,” Shipley said. “But from the standpoint of protecting the whole body, we really don’t have enough to do that anymore.”

That’s something to think about while you’re sitting on your

Coccyx

“It’s something we totally don’t need,” Lu said. Also known as the tailbone, it suffers chronic unemployment, causing its nerves to degenerate.

“We are also losing a certain nerve in the spine,” Lu said. “It’s still there, but it’s difficult to find. You have to use something to make it remain useful.”

We can afford to lose certain other bones and muscles, Lu said. Which is the cue for

Certain Other Bones and Muscles

While its name may sound like a nightmare from Jurassic Park, the coracobrachialis is a muscle that hangs out in the upper and medial arm. Its job is handled quite ably by the bicep, Lu said.

Further south, on the road to “Toe-ville,” is the plantaris muscle, a partner with the Achilles tendon in ankle- and knee-joint flexing. Some people don’t even have one.

“It does help other muscles work better,” Lu said. But it’s more practical if you enjoy running, he said. Less so if dethroning Usain Bolt is not your dream.

When certain muscles are damaged, Lu said, their backups take over, and primary muscles almost always have one. That’s what physical therapists do: Help patients strengthen the benchwarmers so they can join the starting lineup.

While backup bones don’t seem to be a thing, there are some superfluous ones, Lu said.

“In the foot, do we really need that many bones? Wouldn’t one, big, powerful one be safer instead of so many fragile ones?”

Spoiler alert: The answer begins with a “y.”

Addendum, A.K.A. Appendix (the Other Kind)

“You can lose part of the small intestine, you can lose part of the liver, you can lose a lung, and it’s no big deal,” Lu said. “All organs are very powerful, so we can afford to lose half their function.

“But to lose that completely, you have consequences.”

Consider the consequences of surrendering your spleen. This fist-shaped organ, coming in a shade or two lighter than the eggplant, is sometimes surgically removed, often after a devastating traffic accident. But its absence makes the liver grow fonder.

Spleen-less, the body must rely exclusively on the liver to remove certain toxins. Increased bacterial infection is a risk “if you eat something bad,” Lu said.

The spleen also helps fight bacteria that cause pneumonia and meningitis.

“I don’t think I would like to lose my spleen,” Conway said.

In the gross anatomy lab, students sometimes mistake the spleen for a kidney.

“When they do find the spleen, they’re surprised – ‘Isn’t this small?’ they say.”

Students have met other surprises:

    •  Missing muscles,

    •  Blood vessels in the wrong place,

    •  Two superior venae cavae (the large vein carrying deoxygenated blood into the heart); one is standard issue, and

    •  A lung compressed to the size of the spleen and forced out of position by a herniated stomach.

That last anomaly was detected by a dental student, Lu said: Because there was no evidence that the body donor had undergone surgery to fix it, she had apparently decided to live with it, even though whatever she ate must have regurgitated into her esophagus.

“She would have felt that burn,” Lu said.

These discoveries are all part of what Conway called “the mystery of the body.” It is so mysterious that the definition of the word “organ” doesn’t seem to be cut-and-dried.

Take the mesentery. Never heard of it? It is, in a way, the spiritual brother of Pluto, so recently demoted from planet to dwarf.

The status of the mesentery, which links the intestines and other organs to the abdominal wall, has swung from “organ first-class” to “fragmented membrane” and back. Apparently, it has been un-demoted, confirming Leonardo da Vinci’s verdict from a few hundred years ago.

The mesentery is a special type of fascia, or internal connective tissue, that is everywhere, Lu said. Understanding it better may help to diagnose diseases and other issues and improve treatment.

Who knows? Maybe one day it will be mentioned in the same breath with the heart and the brain. Although, “cross my mesentery and hope to die” doesn’t have quite the same ring.

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