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.

Why Do We Get Shivers Up Our Spines?


Picture this: You're sitting on your couch in the dark alone, watching a scary movie. The killer is walking toward an unsuspecting victim, then suddenly jumps out at her. In that moment, the hairs on your body stand up, and you get a shiver down your spine. When you go for a walk on a crisp morning, the same thing happens. When the music swells during your favorite song, you get the shivers again, this time with the little goosebumps on your arms that appear when you get that sensation.

There's a good reason for shivers and goosebumps: they're your body's response to emotion or stress. We got this from our animal ancestors. When they were cold, the hair on their bodies would stand up—the movement of the arrector pili muscle would cause the skin to contract, raising each hair—to provide an extra layer of insulation. This response is also in play when animals feel threatened: their natural reaction is to try to look bigger than their attacker, so their skin and hair expand to play up that effect. The part of the brain called the hypothalamus is what controls this reaction.

So why do goosebumps—also known as cutis anserina or piloerection—appear, aside from the functional purpose of looking larger or creating insulation? It's because our emotions are also connected with the hypothalamus, so sometimes goosebumps are just our body reacting to our brain's signals of intense emotion.

When we feel things like love, fear, or sadness, the hypothalamus sends a signal to our bodies that produces adrenaline in our blood. The signal triggers the arrector pili muscles to contract, and then we have goosebumps caused by emotion. The sudden adrenaline rush may also cause sweaty palms, tears, increased blood pressure, or shivers.

When we listen to music and get shivers, it is a mixture of subjective emotions toward the music and physiological arousal. If we hear a song we get excited about, or a song that makes us sad, the hypothalamus reacts to the sudden change in emotion and we physically feel the shiver along our spine.

This article was republished in 2019.

10 Facts About the Lungs


Every cell in your body needs oxygen in order to function properly. Your lungs are obviously crucial in achieving this goal—once you take air into your lungs, oxygen enters the bloodstream and moves through your body. Each cell makes a trade, exchanging oxygen for carbon dioxide—which your bloodstream then transports back to the lungs. When you exhale, you’re actually expelling carbon dioxide (CO2), nitrogen, and water vapor.

So how does your body make this happen? Bronchial tubes connect your lungs to your throat and mouth. These are lined with tiny little hairs called cilia that move in wave-like patterns, which pushes mucus up your throat. At the base of the bronchial tubes are tiny air sacs that hold the air you breathe in, called alveoli. Your right lung has three balloon-like sections, called lobes, which are full of spongy tissue. Your left lung has only two lobes, to make room for the heart. They sit in a special membrane called the pleura, that separates your lungs from the wall of your chest. Altogether, your lungs are a highly efficient machine—and they do a lot more than you might think.

1. Taking in oxygen is only one of your lungs' most important jobs. 

Yes, you need oxygen to live, but if you didn’t expel the carbon dioxide in your lungs, you would die. Carbon dioxide acts as an acid in the body and is generated by muscle action, Wendie Howland, a nurse with Howland Health Consulting, tells Mental Floss. “Your body operates optimally at a fairly narrow pH range, and when you generate extra CO2 by, say, running up the stairs, you bring your pH into the normal range almost immediately by excreting CO2 by breathing deeply.” So exhaling that more toxic CO2 is as important as taking in oxygen.

2. Think of your lungs as big ol' buckets.

Rather than thinking of your lungs as big balloons, Cascari says, “Think of your lungs as buckets of blood with air bubbles going through them.” In fact, your lungs contain as much blood as the entire rest of your body, which is why your center of gravity is above your waist. They produce blood cells as well. Every time your heart beats, it sends an equal amount of blood to your lungs as it does everywhere else in your body. “It’s this incredible system that can respire—an exchange of gas from the air into the blood and the lungs—without leaking. The fact that that goes on day in day out for our whole life is pretty amazing,” he says.

3. Your lungs are huge.

Your lungs are one of your biggest organs, but you might be surprised to learn that if you spread out the surface area of the alveoli, the sacs where oxygen and blood interface, you could cover an entire tennis court, Schroeder says.

4. Without mucus, your lungs would dry up. 

You may not be a big fan of mucus when it’s clogging your chest or nose during a cold, but it’s a “highly underrated, powerful infection-fighting agent in your body with some pretty cool features," says Ray Casciari, a pulmonologist at St. Joseph Hospital in Orange, California. “It’s actually cleaner than blood,” Casciari reveals. “If you take bacteria and expose it to mucus, the mucus will stop the growth of the bacteria. Whereas blood will actually support the growth of the bacteria.” (In fact, researchers in laboratories often deliberately use blood to grow bacteria.) Your mucus is such an important protective agent that you’d die without it. “If you didn’t have mucus in your lungs, you would dehydrate, losing so much water through evaporation that you would die within minutes,” he says. On the other hand, too much mucus production is dangerous.

5. Whatever you inhale quickly goes from your lungs to your brain. 

In under seven seconds, to be precise. Because of your lungs’ enormous surface area and “its intimate relationship with blood vessels that surround it,” says Scott Schroeder, director of Pediatric Pulmonary Medicine at the Floating Hospital of Tufts Medical Center, an inhalation of smoke or a vaporized medicine can reach the brain very quickly.

6. Coughing isn't always bad for your lungs.

Even when you aren’t sick, a normal person coughs about 10 times per day, says Schroeder—whether due to a sticky piece of food, an allergen you accidentally inhale, or your own mucus generated by exercise.

7. Asthma isn't just one disease affecting lung function.

Asthma, which causes wheezing, coughing, and shortness of breath, is actually a number of different illnesses under one name, Schroeder says. The good news is that deaths due to asthma are very uncommon, and have decreased significantly over the last 20 years, he reports (with one notable exception—African-American men age 18–24). But it doesn’t affect everyone equally. Women are much more likely to develop asthma as adults than men, especially if they are overweight. And people in urban areas are more likely to suffer from asthma than those in rural areas, likely due to increased particulate matter in the air from car exhaust and industrial pollutants.

8. Exercise can make asthma—and your lung function—better.

Asthma is actually improved by cardiovascular exercise. Schroeder says there are no sports that people with asthma cannot participate in, “except scuba diving, but I don’t consider that a sport.”

9. You can get lung cancer even if you've never smoked.

“You can spend your whole life in a very clean environment, never having smoked, and still get lung cancer,” Casciari says. Not all lung cancer is caused by cigarette smoking (though the majority is). Casciari cites occupational exposure, radiation exposure, and potential genetic risk factors, although researchers are still exploring the role genetics play. “Folks tend to think of their lungs very little, and when they do, they think, ‘I don’t smoke, so I’m ok,’ but that’s not completely true.”

10. Breakthroughs in lung cancer treatments has improved survival rates. 

For decades, toxic chemotherapy has been the best medicine for treating lung cancer, but it comes with intense side effects. However, several new breakthroughs have recently improved outcomes for patients, says Casciari. Thoracic CT scans, for example, improve survival by 20 percent by providing earlier diagnosis and treatments. Furthermore, new minimally invasive surgery techniques have made recovery from lung cancer surgery much easier, with people being discharged on the same day of surgery. Finally, immunotherapies that target specific cancer markers and harness the immune system itself to fight cancer cells have improved outcomes—and decreased side effects—for lung cancer patients.

This story was first published in 2017.