12 Facts About the Liver

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You may not think much of your liver, hidden as it is deep inside your body, but your liver runs a whole lot of functions on your behalf to keep you healthy. Not only is it your largest internal organ, it is in charge of hundreds of different functions ranging from fighting infection, to manufacturing proteins and hormones, and helping clot your blood.

This reddish brown organ has two lobes, on the right and left, and it hangs out just on top of the gallbladder and next to parts of the pancreas and intestines. Your liver and these neighboring organs work as a team to digest and absorb your food. Its main job is to filter the blood that comes from the digestive tract, before it hits the rest of your body. The liver also detoxifies chemicals and metabolizes drugs. As it does so, the liver secretes bile that ends up back in the intestines. The liver also makes proteins important for blood plasma and other functions. With some expert support, here are 12 facts about this underappreciated, hardworking organ.

1. IT HAS A LOT OF JOBS.

The liver is a very complicated organ with a role in nearly every bodily function, according to Nancy Reau, MD, the section chief of hepatology and associate director of organ transplantation at Rush University. Some of its jobs include making and storing energy; producing proteins vital for body function; processing drugs—prescriptions, OTCs, and “drugs of abuse”; and playing a vital role in immune function. “Although it’s hard to quantify all of the liver’s many roles, it is easy to see how sick a person becomes when the liver stops functioning,” says Reau, who is also co-chair of the American Liver Foundation’s medical advisory committee.

2. IT'S THE SECOND BIGGEST ORGAN NEXT TO SKIN.

Your liver weighs about the same as a small Chihuahua, often as much as three pounds [PDF], and is about the size of a football. It's located just beneath your rib cage on the right side of your body. If you could feel it, it would be rubbery to the touch.

3. IT HAS A DUAL IDENTITY.

Organs usually have a job specific to one region of the body. Glands are specialized types of organs that remove substances from the blood, alter or process them, then release them to other parts of the body or eliminate them. In that respect, the liver, which filters your body’s toxins (such as drugs and alcohol) and pushes them out of your body, is also a gland.

4. IT'S A BLOODY ORGAN.

At its fullest, the liver holds approximately 10 percent of the blood in your body, and pumps nearly 1.5 liters through itself per minute.

5. THE FIRST LIVER TRANSPLANT WAS NOT A GREAT SUCCESS.

Back in 1963, when Dr. Thomas E. Starzl performed the first human liver transplant at the University of Colorado Medical School, success was limited due to the wrong kinds of immunosuppressive drugs, with no patient living more than a few weeks. However, only four years later, the expansion of available immunosuppressive drugs made the first successful liver transplant possible.

6. IT'S THE ONLY ORGAN THAT CAN COMPLETELY REGENERATE.

Like Wolverine, the liver has the incredible ability to completely regrow, and it only needs as little as 25 percent of the original tissue to do so. “When a person donates more than half of their liver to someone who needs a transplant, the liver returns to its original size in nearly two weeks,” Reau tells Mental Floss. According to a 2009 study in the Journal of Cell Physiology, evolutionary safeguards are responsible for this regenerative effect due to the numerous functions performed by the liver. “This process allows liver to recover lost mass without jeopardizing viability of the entire organism,” the authors write.

7. GOOD THING, BECAUSE YOUR BRAIN DEPENDS ON A HEALTHY LIVER.

The liver is a major regulator of plasma glucose and ammonia levels. If these get out of control they can contribute to a condition known as hepatic encephalopathy, and eventually coma. In other words, if you want your brain to function, you need a working liver.

8. LIVER CONDITIONS MAY BE SYMPTOMLESS.

Liver conditions are among those that pose a quandary for diagnosis. Because many liver conditions from hepatitis to cirrhosis may have no symptoms in the early stages. “You can even have a serious liver injury when your liver tests are all normal,” says Reau.

9. BEWARE YOUR NATURAL SUPPLEMENTS, TOO.

You may think if an herb or supplement has the word natural on the bottle that it’s safe. However, Reau cautions, “Herbs and all-natural therapy [are] processed by the liver in the same way that FDA-approved medications are processed.” It’s best to talk with your doctor if you’re uncertain. Although liver injury is uncommon for both prescribed and complementary therapies, being “all natural” does not eliminate all risk.

10. YOUR LIVER IS CONCERNED ABOUT YOUR WEIGHT …

Your body needs about one gram (.03 ounces) of liver for every kilogram (35 ounces) of your body weight in order to effectively do its job, Dr. Neil Mukherjee, a liver surgeon and fellow at Florida Hospital's Southeastern Center for Digestive Disorders & Pancreatic Cancer, tells Mental Floss.

11. … AND IT RAISES YOUR BILE.

The liver is a busy brew factory of bile, that yellow, green or brownish fluid you only ever see when you’re greeting the toilet with the stomach flu or a hangover. It produces about 700 to 1000 ml of the stuff every day. The bile gathers in little ducts and then moves on to the main bile duct, where it’s carried to the duodenum of the small intestine, either directly or via the gallbladder. While it may sound gross, bile is key to your body's ability to break down and absorb fats.

12. NO MATTER SHAPE OR SIZE, ALL VERTEBRATES HAVE ONE.

Every vertebrate—that is, any living being that has a spinal cord—has a liver, a necessary part of survival. And, these livers all have a similar structure, performing the same essential tasks in all these bodies.

12 Facts About the Sense of Taste

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A lot more than your tongue is involved in the process of tasting food. Taste is not only one of the most pleasurable of the five senses, but a surprisingly complex sense that science is beginning to understand—and manipulate. Here are 12 fascinating facts about your ability to taste.

1. Everyone has a different number of taste buds.

We all have several thousand taste buds in our mouths, but the number varies from person to person. The average range is between 2000 and 10,000. And taste buds are not limited to your tongue; They can be found in the roof and walls of your mouth, throat, and esophagus. As you age, your taste buds become less sensitive, which experts believe may be why foods that you don’t like as a child become palatable to you as an adult.

2. You taste with your brain.

The moment you bite into a slice of pie, your mouth seems full of flavor. But most of that taste sensation is happening in your brain. More accurately, cranial nerves and taste bud receptors in your mouth send molecules of your food to olfactory nerve endings in the roof of your nose. The molecules bind to these nerve endings, which then signal the olfactory bulb to send smell messages directly to two important cranial nerves, the facial nerve and the glossopharyngeal nerve, which communicate with a part of the brain known as the gustatory cortex.

As taste and nerve messages move further through the brain, they join up with smell messages to give the sensation of flavor, which feels as if it comes from the mouth.

3. You can’t taste well if you can’t smell.

When you smell something through your nostrils, the brain registers these sensations as coming from the nose, while smells perceived through the back of the throat activate parts of the brain associated with signals from the mouth. Since much of taste is odor traveling to olfactory receptors in your brain, it makes sense that you won’t taste much at all if you can’t smell. If you are unable to smell for reasons that include head colds, smoking cigarettes, side effects of medications, or a broken nose, olfactory receptors may either be too damaged, blocked, or inflamed to send their signals on up to your brain.

4. Eating sweet foods helps form a memory of a meal.

Eating sweet foods causes your brain to remember the meal, according to a 2015 study in the journal Hippocampus, and researchers believe it can actually help you control eating behavior. Neurons in the dorsal hippocampus, the part of the brain central to episodic memory, are activated when you eat sweets. Episodic memory is that kind that helps you recall what you experienced at a particular time and place. "We think that episodic memory can be used to control eating behavior," said study co-author Marise Parent, of the Neuroscience Institute at Georgia State. "We make decisions like 'I probably won't eat now. I had a big breakfast.' We make decisions based on our memory of what and when we ate."

5. Scientists can turn tastes on and off by manipulating brain cells.

Dedicated taste receptors in the brain have been found for each of the five basic tastes: sweet, sour, salty, bitter, and umami (savory). In 2015, scientists outlined in the journal Nature how they were able to turn specific tastes on or off in mice, without introducing food, by stimulating and silencing neurons in the brains. For instance, when they stimulated neurons associated with “bitter,” mice made puckering expressions, and could still taste sweet, and vice versa.

6. You can tweak your taste buds.

Most of us have had the experience of drinking perfectly good orange juice after brushing our teeth, only to have it taste more like unsweetened lemon juice. Taste buds, it turns out, are sensitive enough that certain compounds in foods and medicines can alter our ability to perceive one of the five common tastes. The foaming agent sodium lauryl/laureth sulfate in most toothpaste seems to temporarily suppress sweetness receptors. This isn't so unusual. A compound called cynarin in artichokes temporarily blocks your sweet receptors. Then, when you drink water, the cynarin is washed away, making your sweet receptors “wake up” so the water tastes sweet. A compound called miraculin, found in the herb Gymnema sylvestre, toys with your sweet receptors in a similar way.

7. The smell of ham can make your food “taste” saltier.

There’s an entire industry that concocts the tastes of the food you buy at the grocery store. Working with phenomena known as phantom aromas or aroma-taste interactions, scientists found that people associate “ham” with salt. So simply adding a subtle ham-like scent or flavor to a food can make your brain perceive it as saltier than it actually is. The same concept applies to the scent of vanilla, which people perceive as sweet.

8. Your taste buds prefer savory when you fly.

A study by Cornell University food scientists found that loud, noisy environments, such as when you’re traveling on an airplane, compromise your sense of taste. The study found that people traveling on airplanes had suppressed sweet receptors and enhanced umami receptors. The German airline Lufthansa confirmed that on flights, passengers ordered nearly as much tomato juice as beer. The study opens the door to new questions about how taste is influenced by more than our own internal circuitry, including our interactions with our environments.

9. Picky eaters may be “supertasters.”

If you’re a picky eater, you may have a new excuse for your extreme dislike of eggplant or sensitivity to the slightest hint of onion. You might be a supertaster—one of 25 percent of people who have extra papillae in your tongue. That means you have a greater number of taste buds, and thus more specific taste receptors.

10. Some of your taste preferences are genetic.

While genetics may not fully explain your love of the KFC Double Down or lobster ice cream, there may be code written into your DNA that accounts for your preference for sweet foods or your aversion to certain flavors. The first discovery of a genetic underpinning to taste came in 1931, when chemist Arthur Fox was working with powdered PTC (phenylthiocarbamide), and some of the compound blew into the air. One colleague found it to have a bitter taste, while Fox did not perceive that. They conducted an experiment among friends and family and found wide variation in how (and whether) people perceived the flavor of the PTC to be bitter or tasteless. Geneticists later discovered that the perception of PTC flavor (similar to naturally occurring compounds) is based in a single gene, TAS2R38, that codes for a taste receptor on the tongue. In a 2005 study, researchers at the Monell Chemical Senses Center found that the version of this gene also predicted a child's preference for sweet foods.

11. Your genes influence whether you think cilantro tastes like soap.

There may be no flavor more hotly debated or deeply loathed than the herb cilantro (also known as coriander). Entire websites, like IHateCilantro.com, complain about its “soapy” or “perfumy” flavor, while those who like it simply think it gives a nice kick to their salsa. Researchers at the consumer genetics company 23andMe identified two common genetic variants linked to people's “soap” perceptions. A follow-up study in a separate subset of customers confirmed the associations. The most compelling variant can be found within a cluster of olfactory receptor genes, which influence our sense of smell. One of those genes, OR6A2, encodes a receptor that is highly sensitive to aldehyde chemicals, which cilantro contains.

12. Sugar cravings have a biological basis.

Your urge for more hot fudge may have little to do with a lack of self-control. Scientists think that our yearning for sweets is a biological preference that may have been designed to ensure our survival. The liking for sweet tastes in our ancient evolution may have ensured the acceptance of sweet-tasting foods, such as breast milk and vitamin-rich fruits. Moreover, recent research suggests that we crave sweets for their pain-reducing properties.

12 Facts About the Pancreas

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You could live without your pancreas, but it wouldn’t be easy. For one, you would need to give yourself insulin shots on a daily basis because you would develop diabetes. A helping of enzyme pills would also be needed to help you digest food. It's clear that the 6-inch-long pancreas, located behind your stomach, has crucial functions—and that's why diseases like pancreatic cancer and pancreatitis are often so devastating. Here are a few other important facts to know about the pancreas.

1. Pancreas means “all flesh” in Greek.

Around 300 BCE, a surgeon in ancient Greece named Herophilus became the first person to formally describe the pancreas as a gland. However, the organ didn’t get its name until about 400 years later, when another Greek surgeon and anatomist named Ruphos dubbed it the pankreas, meaning “all flesh”—possibly because of its lack of bone or cartilage. (The plural of pancreas, by the way, is pancreata or pancreases.) Later, in the 16th century, people started referring to a dish of cooked calf or lamb pancreas as “sweetbreads.” That name possibly stems from bræd, the Old English word for “flesh.”

2. The pancreas has a head and a tail.

The pancreas has four main parts: the head, neck, body, and tail. The widest part is the head, which is attached to the first part of the small intestine, known as the duodenum. In cases where a pancreatic tumor is present, the head is usually the part that’s affected. However, according to one study from 2008, people with tumors in the body or tail of the pancreas had lower survival rates than those with cancer in the head of the pancreas.

3. The man who discovered the pancreatic duct may have been murdered for his work.

The pancreatic duct is a tiny tube that runs the length of the pancreas and carries digestive juices to the duodenum. Although the ancient Greeks knew about the pancreas, its function and anatomy weren’t fully understood for centuries. That started to change in 1642, when German anatomist Johann Georg Wirsung discovered the pancreatic duct after performing a dissection on a man who had been hanged for murder. He named it the “duct of Wirsung” after himself, which may have upset some people. Wirsung was murdered the following year, allegedly over a disagreement as to who had actually discovered the duct.

4. It functions as both an endocrine and exocrine gland.

Although food never enters the pancreas, the organ does play a key role in digestion. It produces pancreatic fluid, which gets piped through the pancreatic duct to the duodenum. Once it’s in the digestive tract, the enzymes in the fluid help break down fat, protein, and carbohydrates. By sending a substance through ducts to other parts of the body, it functions as an exocrine gland. At the same time, it also functions as an endocrine gland by secreting two hormones directly into the bloodstream to help control blood sugars. Insulin is released when you have too much sugar, and glucagon is released when you don’t have enough sugar.

5. The pancreas can “taste” sugar.

The pancreas has taste receptor cells that let it sense the presence of sugar. It can “taste” artificial sweeteners, too. However, unlike the taste buds on our tongue, it doesn’t relay these sensations back to the brain. Instead, this sensory information helps the pancreas balance out the hormones and maintain healthy glucose levels in the body.

6. Diabetes is the result of damage to pancreatic cells.

For reasons that remain a scientific mystery, people with type 1 diabetes have immune systems that attack the insulin-producing cells in their pancreas. This prevents the cells from making insulin, and without insulin, other cells can't access the glucose in the bloodstream for energy. Sugar then builds up unhealthily in the bloodstream. People with type 2 diabetes, on the other hand, can still produce some insulin, but it’s not enough. Their cells become resistant to insulin (often as a result of obesity), which causes glucose to accumulate in the bloodstream.

7. The pancreas can digest itself.

Pancreatitis refers to the inflammation of the pancreas, but more alarmingly, what’s actually happening is that the digestive enzymes in the gland are going rogue and “digesting the pancreas itself,” according to Medline Plus. Heavy alcohol consumption is the most common cause of the disease, but other causes may include gallstones, cystic fibrosis, or high levels of fats or calcium in the blood. Most people with acute pancreatitis end up in the hospital, and it often goes away in a couple of days. Chronic pancreatitis can result in more serious complications.

8. Scorpion stings can cause pancreatitis.

The venom of a Brazilian scorpion, Tityus serrulatus, can cause pancreatitis, according to researchers at North Carolina State University. One particular enzyme in the venom attacks certain proteins in the gland, which impairs the pancreatic cells' functions and leads to inflammation. In a separate study of a related species (T. stigmurus), researchers found that “acute pancreatitis due to scorpion is usually transient [and] self-limited ... but it could progress to hemorrhagic pancreatitis and lead to death.”

9. Ruth Bader Ginsburg beat the odds and survived pancreatic cancer.

Ten years after she recovered from colon cancer, Ruth Bader Ginsburg received bad news following a routine check-up in 2009: She had pancreatic cancer. Fortunately, surgeons were able to remove the tumor, and at 85 years old (and counting), Ginsburg is now the oldest Justice on the U.S. Supreme Court. However, most people with pancreatic cancer aren’t so lucky. Although it’s less prevalent than skin, breast, and prostate cancers, it’s one of the deadliest. Just 8 percent of pancreatic cancer patients in the U.S. live longer than five years, according to the American Cancer Society.

James Cleary, an oncologist at the Dana-Farber Cancer Institute in Boston, says it’s very hard to catch in the early stages. “The reason pancreatic cancer can be so difficult to catch is number one, it’s a fast-moving cancer and can grow very rapidly,” he tells Mental Floss. “And number two, it can grow in a spot where you don’t get any symptoms until it’s too late.” In some cases, the cancer may start in the pancreas and spread to the liver or lining of the abdomen without any symptoms showing up.

10. Pancreatic surgery is extremely difficult to pull off.

Sometimes, patients with pancreatic cancer will undergo a complicated surgery called a Whipple procedure, which involves the removal of the head of the pancreas, part of the small intestine, the gallbladder and bile duct, and sometimes part of the stomach, too. However, very few people with pancreatic cancer are candidates for surgery—even if the cancer hasn’t yet spread to neighboring organs. That’s because cancer cells sometimes surround important blood vessels, making it “a tricky area” to operate on, according to Cleary. “The pancreas plays a really important role in digestion, and because of that, it’s very close to several important blood vessels and it’s very close to the stomach and small intestine,” he says.

11. There are genetic components to pancreatic cancer.

More than 90 percent of pancreatic cancers involve a mutation of the KRAS gene, which is also responsible for about half of all human cancers, according to Cleary. However, a drug hasn’t been invented yet to turn this particular gene off. “Finding a way to make a drug successfully target KRAS is one of holy grails of oncology," Cleary says. "It is of such great importance to oncology that a Nobel Prize could be awarded to whoever figures out how to make effective KRAS targeted therapy."

Mutations of DNA repair genes occur in up to 20 percent of pancreatic cancer cases. Some of these mutated genes, like BRCA1 and BRCA2, can run in families. This is why some families have several members who end up suffering from pancreatic cancer. Jimmy Carter, for example, lost his father, brother, and two sisters to pancreatic cancer. His mother had breast cancer that migrated to her pancreas. PARP inhibitors (drugs that block a particular enzyme) have been used to target DNA repair genes in breast and ovarian cancers, and there is now hope that they may also be effective in treating pancreatic cancer.

12. An aggressive form of chemotherapy is helping pancreatic cancer patients live longer.

A chemotherapy regimen called FOLFIRINOX has made significant improvements in the care of pancreatic cancer patients ever since it was introduced in 2010 as a treatment for patients with metastatic disease. Before 2010, “It was very, very rare to see anyone with metastatic cancer living longer than one year,” Cleary says. With FOLFIRNOX, it's not uncommon to see patients with metastatic pancreatic cancer living two years. A huge step forward came in June 2018 when researchers from France found that giving FOLFIRINOX after surgery could increase survival by a median of 20 months longer compared to the standard chemotherapy. Now, researchers are conducting trials to see if FOLFIRINOX can effectively be administered before a patient undergoes surgery. Considering that most patients aren’t eligible for surgery at diagnosis, pre-operative FOLFIRINOX could shrink the pancreatic tumor and increase the number of patients that are able to safely receive surgery.

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