12 Facts About the Gallbladder


Don't feel too bad if you forgot you have a gallbladder—it's one of those body parts that people tend to ignore unless there's a problem. Here's a refresher: It's that small pouch beneath the liver whose primary function is to store bile, which helps you digest fats. So the next time you wolf down a Quarter Pounder with cheese, you can thank your gallbladder for doing its part. Here are a few other things you should know.


Right before you take your first bite of pizza, your gallbladder is full of bile—an alkaline fluid that's produced in the liver, transported to the gallbladder, and then released into the small intestine to help break down fat and bilirubin, a product of dead red blood cells. The organ can hold the equivalent of a shot glass of the yellow-green liquid, which causes it to swell up to the size of a small pear.

When you eat certain foods—especially fatty ones—the gallbladder releases the bile and deflates like a balloon. Although most gallbladders are roughly 1 inch wide and 3 inches long, there are notable exceptions. In 2017, a gallbladder removed from a woman in India measured nearly a foot long, making it the longest gallbladder in the world.


You don’t need your gallbladder to live a full and healthy life. Just ask British playwright Mark Ravenhill, who wrote an account for the BBC about getting his gallbladder removed after a gallstone—a solid object made of cholesterol or calcium salts and bilirubin—had moved painfully into his pancreas. "'The gallbladder's completely useless,'" Ravenhill recalled his doctor explaining. "'If it's going to be a problem, best just to take it out.'"

In addition to preventing more gallstones from forming, a physician may recommend that a patient’s gallbladder be removed due to other diseases, like cholecystitis (inflammation of the gallbladder) and cancer. In most cases, removing it doesn’t affect digestion, but there can be some complications. "People can certainly live without one, but they do have to watch their fat intake," says Ed Zuchelkowski, an anatomist and biology professor at California University of Pennsylvania. People who don't have gallbladders still produce bile, but it flows directly from the liver to the small intestine. The only difference is that "you would not have as much bile readily available to release," Zuchelkowski tells Mental Floss, which could cause minor problems like diarrhea if you're eating fatty foods.


"[The gallbladder] probably was more important to people in days when they would eat fewer meals and larger meals," Zuchelkowski says. This was generally the situation that our hunter-gatherer ancestors found themselves in. As Ravenhill notes, "feast or famine was the general rule." Nomadic groups ate large slabs of meat about once a week, and the gallbladder helped to quickly digest the onslaught of protein and fat.

Even though our diets and eating habits have changed drastically since then, evolution hasn't caught up—we still have the same digestive system. It's probably for this reason that "most meat-eating animals have a gallbladder," Zuchelkowski says. "Dogs do, cats do—they can concentrate bile just like we do, but I think you’d find that in animals that only eat vegetation, that’s where it’s likely to be missing.” However, Zuchelkowski notes that the gallbladder also helps you absorb fat-soluble vitamins like A, D, E, and K, so it still serves a useful function in people who are vegetarians.


A 2012 report from the Canadian Journal of Surgery recommended that astronauts consider having their appendix and gallbladder removed—even if their organs are perfectly healthy—to prevent appendicitis, gallstones, or cholecystitis from setting in when they’re far, far away from Earth's hospitals. “The ease and safety of surgical prophylaxis currently appears to outweigh the logistics of treating either acute appendicitis or cholecystitis during extended-duration space flight,” the authors wrote.


Alexander may have been great at conquering entire empires, but his organs weren’t exactly up to the task. The king of Macedonia died at the age of 34, and some historians believe that the cause was peritonitis (inflammation of the peritoneum, the tissue lining the abdomen), which itself was a result of acute cholecystitis. “Historians have suggested that the fatal biliary tract disease was fueled by excess consumption of alcohol and overeating at a banquet that Alexander threw for his leading officers in Babylon,” author Leah Hechtman writes in Clinical Naturopathic Medicine.


Gallbladder-related ailments have been afflicting humans for thousands of years, as evidenced by gallstones found in Egyptian mummies. And for thousands of years, people put up with it because they didn’t know what was wrong or how to fix it. In fact, it wasn’t until 1867 that the first cholecystotomy (removal of gallstones) was carried out. The surgery was performed by Dr. John S. Bobbs of Indianapolis, who had no idea what ailed his patient, 31-year-old Mary Wiggins, until he cut open a sac that he later realized was her gallbladder and “several solid bodies about the size of ordinary rifle bullets” fell out, according to The Indianapolis Star. Amazingly, Wiggins survived and lived to the age of 77. Fifteen years after this surgery, the first cholecystectomy (removal of the gallbladder) was performed in Germany.


Unlike the Guinness World Record for most Twinkies devoured in one sitting, this isn’t the kind of record you’d enjoy setting. In 1987, an 85-year-old woman complaining of severe abdominal pain showed up at Worthing Hospital in West Sussex, England, and doctors found a shockingly high number of gallstones—23,530, to be exact. In May 2018, a similar (albeit less severe) case of gallstones was reported in India, where a 43-year-old man underwent surgery to have thousands of them removed. “Usually we get to see two to 20 stones, but here there were so many and when we counted them, it was a whopping 4100,” the surgeon told Fox News.


Some practitioners of Eastern medicine—especially Traditional Chinese Medicine (TCM)—purport that gallbladder problems can cause certain kinds of headaches. TCM practitioners say our internal organs are connected to channels called meridians, which direct several fundamental substances—like blood, other bodily fluids, and qi (vital life energy)—throughout the body. The gallbladder meridian, for instance, runs along the side of the head near the temple. Through the practice of acupuncture, tiny needles are inserted into the skin along the gallbladder meridian in an effort to relieve tension and free up blocked qi. (Western scientists tend to disagree on what, if any, benefit acupuncture offers.)


Speaking of China, the country's primary language, Mandarin, hints at a link between organ function and personality. For instance, a word that’s assigned to bold and daring people translates to “big gallbladder,” and brave people are said to have “gallbladder strength,” according to The Conceptual Structure of Emotional Experience in Chinese. The word for coward, on the other hand, translates to “gallbladder small like mouse.” (Interestingly, mice do in fact have gallbladders, but rats don’t.)


You may remember learning something about the four humors during a high school lesson on ancient Greece. The theory, originating with Hippocrates, held that a person’s temperament was influenced by one of four bodily fluids: black bile, yellow bile, phlegm, and blood. Yellow bile, stored in the gallbladder, was said to make people choleric, or irritable. Disease was blamed on an imbalance of these four humors, and this remained a popular theory up until the 18th century. Because of this theory's longstanding influence, the word gall—a synonym for bile—also meant “embittered spirit” during medieval times. It wasn’t until 1882 that the word took on the meaning of "impudence" or "boldness" in American English—as in “I can’t believe he had the gall to finish that Netflix series without me.”


Well, not human gallbladders. Ancient Etruscans, a group of people who once lived in present-day Tuscany and whose civilization became part of the Roman empire, practiced a type of divination called haruspicy. The soothsayers were called haruspices (literally “gut gazers”), and they looked for clues from the gods in the markings, coloring, and shape of a sacrificial sheep’s liver and gallbladder. This was often done before the Romans went into battle, but the practice was never adopted as part of the state religion.


A crease called a "Phrygian cap" at the base of the gallbladder occurs in about 4 percent of people. Its odd name is something of a misnomer. It comes from its resemblance to a type of peaked felt hat called a pileus, worn by emancipated slaves in ancient Rome; the design was similar to the peaked caps then worn in Phrygia, a region in modern-day Turkey. Much later, during the French Revolution, people took to wearing Phrygian caps—which they likely confused with the pileus's style—as symbols of their freedom from tyranny. In the 20th century, the Smurfs started wearing them.

As for the aforementioned gallbladder abnormality, there’s no deeper symbolism in its name. The way it folds over just looks a lot like a Phrygian cap. Despite being a “congenital anomaly,” as a 2013 study published in Case Reports in Gastroenterology puts it, the condition typically causes no symptoms or complications.

25 Amazing Facts About the Human Body


The human body is an amazing piece of machinery—with a few weird quirks.

  1. It’s possible to brush your teeth too aggressively. Doing so can wear down enamel and make teeth sensitive to hot and cold foods.

  2. Goose bumps evolved to make our ancestors’ hair stand up, making them appear more threatening to predators.

Woman's legs with goosebumps
  1. Wisdom teeth serve no purpose. They’re left over from hundreds of thousands of years ago. As early humans’ brains grew bigger, it reduced space in the mouth, crowding out this third set of molars.

  2. Scientists aren't exactly sure why we yawn, but it may help regulate body temperature.

  3. Your fingernails don’t actually grow after you’re dead.

  4. If they were laid end to end, all of the blood vessels in the human body would encircle the Earth four times.

  5. Humans are the only animals with chins.

    An older woman's chin
    1. As you breathe, most of the air is going in and out of one nostril. Every few hours, the workload shifts to the other nostril.

    2. Blood makes up about 8 percent of your total body weight.

    3. The human nose can detect about 1 trillion smells.

    4. You have two kidneys, but only one is necessary to live.

    5. Belly buttons grow special hairs to catch lint.

      A woman putting her hands in a heart shape around her belly button
      1. The satisfying sound of cracking your knuckles comes from gas bubbles bursting in your joints.

      2. Skin is the body’s largest organ and can comprise 15 percent of a person’s total weight.

      3. Thumbs have their own pulse.

      4. Your tongue is made up of eight interwoven muscles, similar in structure to an elephant’s trunk or an octopus’s tentacle.

      5. On a genetic level, all human beings are more than 99 percent identical.

        Identical twin baby boys in striped shirts
        1. The foot is one of the most ticklish parts of the body.

        2. Extraocular muscles in the eye are the body’s fastest muscles. They allow both of your eyes to flick in the same direction in a single 50-millisecond movement.

        3. A surgical procedure called a selective amygdalohippocampectomy removes half of the brain’s amygdala—and with it, the patient’s sense of fear.

        4. The pineal gland, which secretes the hormone melatonin, got its name from its shape, which resembles a pine nut.

        5. Hair grows fast—about 6 inches per year. The only thing in the body that grows faster is bone marrow.

          An African-American woman drying her hair with a towel and laughing
          1. No one really knows what fingerprints are for, but they might help wick water away from our hands, prevent blisters, or improve touch.

          2. The heart beats more than 3 billion times in the average human lifespan.

          3. Blushing is caused by a rush of adrenaline.

12 Intriguing Facts About the Intestines

When we talk about the belly, gut, or bowels, what we're really talking about are the intestines—long, hollow, coiled tubes that comprise a major part of the digestive tract, running from the stomach to the anus. The intestines begin with the small intestine, divided into three parts whimsically named the duodenum, jejunum, and ileum, which absorb most of the nutrients from what we eat and drink. Food then moves into the large intestine, or colon, which absorbs water from the digested food and expels it into the rectum. That's when sensitive nerves in your rectum create the sensation of needing to poop.

These organs can be the source of intestinal pain, such as in irritable bowel syndrome, but they can also support microbes that are beneficial to your overall health. Here are some more facts about your intestines.

1. The intestines were named by medieval anatomists.

Medieval anatomists had a pretty good understanding of the physiology of the gut, and are the ones who gave the intestinal sections their names, which are still used today in modern anatomy. When they weren't moralizing about the organs, they got metaphorical about them. In 1535, the Spanish doctor Andrés Laguna noted that because the intestines "carry the chyle and all the excrement through the entire region of the stomach as if through the Ocean Sea," they could be likened to "those tall ships which as soon as they have crossed the ocean come to Rouen with their cargoes on their way to Paris but transfer their cargoes at Rouen into small boats for the last stage of the journey up the Seine."

2. Leonardo da Vinci believed the intestines helped you breathe.

Leonardo mistakenly believed the digestive system aided respiratory function. In 1490, he wrote in his unpublished notebooks, "The compressed intestines with the condensed air which is generated in them, thrust the diaphragm upwards; the diaphragm compresses the lungs and expresses the air." While that isn't anatomically accurate, it is true that the opening of the lungs is helped by the relaxation of stomach muscles, which does draw down the diaphragm.

3. Your intestines could cover two tennis courts ...

Your intestines take up a whole lot of square footage inside you. "The surface area of the intestines, if laid out flat, would cover two tennis courts," Colby Zaph, a professor of immunology in the department of biochemistry and molecular biology at Melbourne's Monash University, tells Mental Floss. The small intestine alone is about 20 feet long, and the large intestine about 5 feet long.

4. ... and they're pretty athletic.

The process of moving food through your intestines requires a wave-like pattern of muscular action, known as peristalsis, which you can see in action during surgery in this YouTube video.

5. Your intestines can fold like a telescope—but that's not something you want to happen.

Intussusception is the name of a condition where a part of your intestine folds in on itself, usually between the lower part of the small intestine and the beginning of the large intestine. It often presents as severe intestinal pain and requires immediate medical attention. It's very rare, and in children may be related to a viral infection. In adults, it's more commonly a symptom of an abnormal growth or polyp.

6. Intestines are very discriminating.

"The intestines have to discriminate between good things—food, water, vitamins, good bacteria—and bad things, such as infectious organisms like viruses, parasites and bad bacteria," Zaph says. Researchers don't entirely know how the intestines do this. Zaph says that while your intestines are designed to keep dangerous bacteria contained, infectious microbes can sometimes penetrate your immune system through your intestines.

7. The small intestine is covered in "fingers" ...

The lining of the small intestine is blanketed in tiny finger-like protrusions known as villi. These villi are then covered in even tinier protrusions called microvilli, which help capture food particles to absorb nutrients, and move food on to the large intestine.

8. ... And you can't live without it.

Your small intestine "is the sole point of food and water absorption," Zaph says. Without it, "you'd have to be fed through the blood."

9. The intestines house your microbiome. 

The microbiome is made up of all kinds of microorganisms, including bacteria, viruses, fungi, and protozoans, "and probably used to include worm parasites too," says Zaph. So in a way, he adds, "we are constantly infected with something, but it [can be] helpful, not harmful."

10. Intestines are sensitive to change.

Zaph says that many factors change the composition of the microbiome, including antibiotics, foods we eat, stress, and infections. But in general, most people's microbiomes return to a stable state after these events. "The microbiome composition is different between people and affected by diseases. But we still don't know whether the different microbiomes cause disease, or are a result in the development of disease," he says.

11. Transferring bacteria from one gut to another can transfer disease—or maybe cure it.

"Studies in mice show that transplanting microbes from obese mice can transfer obesity to thin mice," Zaph says. But transplanting microbes from healthy people into sick people can be a powerful treatment for some intestinal infections, like that of the bacteria Clostridium difficile, he adds. Research is pouring out on how the microbiome affects various diseases, including multiple sclerosis, Parkinson's, and even autism.

12. The microbes in your intestines might influence how you respond to medical treatments.

Some people don't respond to cancer drugs as effectively as others, Zaph says. "One reason is that different microbiomes can metabolize the drugs differently." This has huge ramifications for chemotherapy and new cancer treatments called checkpoint inhibitors. As scientists learn more about how different bacteria metabolize drugs, they could possibly improve how effective existing cancer treatments are.