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8 Surprising Facts About the Stomach

The human body is an amazing thing. For each one of us, it's the most intimate object we know. And yet most of us don't know enough about it: its features, functions, quirks, and mysteries. Our series The Body explores human anatomy, part by part. Think of it as a mini digital encyclopedia with a dose of wow.

While you may only think of your stomach when you're eating or it catches your attention with a gurgle or burble, it's much more than a repository for the food you eat. Your stomach kills microbes, secretes hormones and mucus, and absorbs nutrients. Here are eight gut-clenching facts you might not have known:

1. IT HAS SOME SERIOUS STORAGE CAPACITY.

Your stomach at rest holds about 7 ounces of stomach acid and bile. However, it has the capacity to hold nearly a half-pound of food at a time if necessary. (The average capacity is about 32 ounces, or a quarter-gallon.) It normally takes from four to six hours to digest one meal, so this capacity can be important.

2. PH BALANCE AND MUCUS PREVENT ACID FROM CORRODING YOUR STOMACH.

"Thanks to the high production of hydrochloric acid, which is highly potent, the stomach regenerates its lining frequently," says Sydney Ziverts, a health and nutrition investigator for ConsumerSafety.org. The stomach cavity has a powerful protective process in place that normally keeps the pH of the stomach balanced. Potassium ions help to modulate the hydrochloric acid, and the stomach lining itself produces high numbers of goblet mucus cells to protect the lining.

3. IT ALLOWS YOU TO ABSORB THE CRUCIAL VITAMIN B12 OUT OF YOUR FOOD.

Your stomach is responsible for helping to release the crucial vitamin B12 [PDF] from the proteins you eat. Hydrochloric acid and an enzyme called pepsin break the locked B12 out of its protein so it can be absorbed into your blood stream. "The metabolism of vitamin B starts in the stomach in the parietal cells," Lisa Ganjhu, associate professor of gastroenterology and hepatology at NYU Langone Medical Center, tells Mental Floss. Vitamin B "is one of the main vitamins in our body to help with metabolism and energy production," she says.

4. IT'S A HORMONE-GENERATING MACHINE.

Eating and digesting your food is most likely something you never have to think about. Yet your GI tract is home to a veritable orchestra of hormones stimulated by epithelial cells that line the stomach and small intestine. These hormones engage in a wide range of functions, including stimulating appetite, encouraging the secretion of enzymes and gastric acid, and reminding the gall bladder to contract and empty. These hormones directly enter the blood, and eventually affect the function of other parts of the digestive system, including the liver and pancreas, and even your brain.

5. YOUR STOMACH IS ONE OF YOUR IMMUNE SYSTEM'S FIRST LINES OF DEFENSE.

Besides just digesting your food, the stomach helps protect your entire body. "The acidity in our stomach helps to sterilize whatever you're eating. It kills off bacteria and potential food toxins," says Ganjhu. Your gastrointestinal tract also has patches of lymphoid defense cells it sends out when something makes it through the stomach, such as a virus or bacterial infection.  

6. AND IT MAY PLAY A PART IN YOUR MOOD, TOO.

Your stomach may very well be a key player in keeping your mood balanced. New research suggests links between the gut microbiome—the microorganisms that live in any environment—and your mental health. A recent study in the Journal of Psychiatric Research found that transferring the gut microbiota of depressed human patients into rats induced depressive symptoms in the rodents, opening up a whole new realm of possible bacteria-based treatments.

7. STOMACH FLU ISN'T ACTUALLY A FLU.

If you've ever had the misfortune to find yourself stranded by the toilet for 24 to 48 hours purging the contents of your stomach, you may have described the cause as a stomach flu. However, actual influenza is primarily a respiratory infection. What keeps you in the bathroom is likely some form of norovirus or rotavirus, which causes gastroenteritis of the stomach and intestines, and usually resolves in one to two days.

8. THE MOST COMMON CAUSE OF STOMACH ULCERS IS LIKELY BACTERIAL.

The causes of ulcers have perplexed medical researchers for years. However, recent studies have found a link between the bacteria H. pylori and inflammation of the stomach lining, gastritis, and ulcers. In fact, new research suggests that the bacteria may also be linked to stomach cancer.

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The Body
9 Interesting Facts About the Ribs
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The human body is an amazing thing. For each one of us, it's the most intimate object we know. And yet most of us don't know enough about it: its features, functions, quirks, and mysteries. Our series The Body explores human anatomy, part by part. Think of it as a mini digital encyclopedia with a dose of wow.

Ribs are not just an incredibly tasty order on the menu at the nearest steak house: These bony spindles in your torso attach to your sternum (breast bone) to protect your lungs, heart, spleen, and most of the liver and help with giving shape to your chest cavity, which assists in breathing. Ribs are protective on the one hand, but if badly broken, your ribs can turn lethal to you, piercing your organs. Mental Floss spoke to John Martinez, MD, an urgent care provider with Dignity Health Medical Foundation in California for these nine fascinating facts about the ribs.

1. YOUR RIBS MOVE LIKE A BUCKET HANDLE.

The ribs allow chest expansion for breathing, Martinez explains. "They function similarly to the bucket handle on a bucket and swing upwards as we take a breath, allowing the thoracic cavity to expand." This increase in the thoracic cavity makes it easier to take a breath.

2. YOU HAVE THREE TYPES OF RIBS.

The human skeleton has 12 pairs of ribs. Working from the top of the torso down, ribs 1 to 7 are considered "true ribs," as they connect directly from the spine to the sternum, Martinez says. Ribs 8 to 10 are called "false ribs" because they don't connect directly, but have cartilage that attaches them to the sternum. Ribs 11 and 12 are called "floating ribs" because they only connect to the spine in back. These, he says, "are much shorter."

3. THIS MYTH ABOUT WOMEN'S RIBS PERSISTS.

In an effort to prove the Bible story of Eve as wrought from Adam's rib "true," pastors and Sunday School teachers sometimes pass along a tale that women have more ribs than men. It's not true (and that story is sexist, anyway). Gender plays no part in the number of ribs you have: It's 12 ribs for everyone. However, women's ribs are about 10 percent smaller in volume on average than men's ribs.

4. IN RARE INSTANCES, HUMANS CAN HAVE A "GORILLA RIB."

In rare cases, which have nothing to do with gender, a human might turn up sporting extra lumbar ribs, for a total of 13 pairs of ribs, much like our distant cousins, the gorillas. Thus, it's colloquially known as a "gorilla rib."

5. RIBS ARE THE REASON NEANDERTHALS DIDN'T NEED BELTS.

Neanderthals had wider, thicker rib cages than we modern slim-waisted humans, which would have made them terrible models for skinny jeans. A 2016 study in American Journal of Physical Anthropology found that the Ice-Age diet is likely responsible for the larger ribcage and wider pelvis in Neanderthals. Essentially, carbs were scarce and fat was abundant. This led to an enlarged liver, kidneys and "their corresponding morphological manifestations," the authors write. In other words, they needed more space to house bigger organs.

6. TWO VERY DIFFERENT KINDS OF ATHLETE SHARE ONE COMMON INJURY. 

"Rowers and baseball pitchers are the most common athletes to suffer from stress fractures of the ribs," Martinez says. This is caused by the serratus anterior muscle pulling on the delicate ribs. "Other athletes that may be more likely to suffer from rib stress fractures include golfers, dancers, weightlifters and volleyball players," he adds.

7. YOU CAN SNEEZE YOUR WAY TO A RIB FRACTURE.

"True" rib fractures—where the bone breaks all the way through—are usually from traumatic events such as "a hard football tackle [or] car accident," Martinez says. However, sometimes a rib fracture can occur "from sneezing or coughing due to the force of the contracting chest wall muscles on the ribs." Treatment for true rib fractures is the same as rib stress fractures.

8. WAIST TRAINING USED TO BE ALL THE RAGE … AND STILL SOMETIMES IS.

Women have historically worn corsets, undergarments that cinch the torso in, particularly at the waist, bringing ribs and organs closer together for a smaller waist and more prominent bust. Despite corsets having gone out of fashion by the 1920s, when women began to prefer the looser, more flowing garments of the Flapper era, a number of contemporary women still wear them for reasons ranging from aesthetics to performance art, spawning a practice known as tight lacing or waist training. In this movement, women actively whittle their waists down to exceptionally small circumferences.

Doctors warn that there is risk of permanent damage to squished organs, as well as such uncomfortable syndromes as acid reflux syndrome and back pain. But it doesn't stop those who love the look.

9. THE GUINNESS RECORD HOLDER FOR A TINY WAIST IS 15 INCHES.

2011 Guinness Book of World Records winner Cathie Jung got her waist down to 15 inches through tight lacing by wearing corsets 24 hours a day, and moving down to smaller and smaller sizes. Her waist now has the same circumference as a regular jar of mayonnaise.

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7 Essential Facts About the Pelvis
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The human body is an amazing thing. For each one of us, it’s the most intimate object we know. And yet most of us don’t know enough about it: its features, functions, quirks, and mysteries. Our series The Body explores human anatomy, part by part. Think of it as a mini digital encyclopedia with a dose of wow.

The pelvis, which crooner Elvis was famous for thrusting around in ways that raised eyebrows, is not actually a single body part but a term that refers to a collection of bones, muscles and organs below the waist. We spoke to Katherine Gillogley, department chair of obstetrics and gynecology with Mercy Medical Group in Sacramento, California, for these seven facts about the pelvis.

1. SO WHAT IS THE PELVIS, EXACTLY?

"The pelvis refers to the lower abdominal area in both men and women," Gillogley says. "An important function of the pelvis region is to protect organs used for digestion and reproduction, though all its functions are crucial," she says. It protects the bladder, both large and small intestines, and male and female reproductive organs. Another key role is to support the hip joints.

2. THE PELVIC BONES FORM A BASIN.

Four bones come together to form a bowl-like shape, or basin: the two hip bones, the sacrum (the triangle-shaped bone at the low back) and the coccyx (also known as the tailbone).

3. YOUR PELVIC FLOOR IS LIKE A TRAMPOLINE.

At the bottom of the pelvis lies your pelvic floor. You don't have to worry about sweeping it, but you might want to do Kegel exercises to keep it strong. The pelvic floor is like a "mini-trampoline made of firm muscle," according the Continence Foundation of Australia. Just like a trampoline, the pelvic floor is flexible and can move up and down. It also creates a surface (floor) for the pelvic organs to lie upon: the bladder, uterus, and bowels. It has holes, too, for vagina, urethra, and anus to pass through.

4. IT PLAYS A KEY PART IN WALKING.

Anyone who has ever broken a pelvic bone or pulled a pelvic muscle will know just how key a role the pelvis plays in such functions as walking and standing. "The pelvis also acts as a solid foundation for the attachment of the spinal column and legs," says Gillogley.

5. THE FEMALE PELVIS STARTS OUT LARGER, BUT NARROWS OVER TIME.

Gillogley says that the female pelvis "tends to be larger and wider" than the male, most likely to accommodate a baby during pregnancy and to make childbirth possible. However, women's pelvises narrow as they age, suggesting that they start out wider to accommodate childbearing and then shift when that is no longer necessary. A shifting pelvis shape is thought to be a key part of our evolutionary history, as it changed as when we began walking upright.    

6. PREGNANCY CHANGES THE PELVIS FOREVER.

During pregnancy the body secretes a hormone known as relaxin to help the body accommodate the growing baby and soften the cervix. However, what happens is, "the joints between the pelvic bones actually loosen and slightly separate during pregnancy and childbirth," Gillogley says. Sometimes, however, relaxin can make the joints too loose, causing a painful syndrome known as symphysis pubis dysfunction (SPD), causing the pelvic joint to become unstable, causing pain and weakness in the pelvis, perineum and even upper thighs during walking and other activities. Many women with the condition have to wear a pelvic belt. It usually resolves after pregnancy is over, though physical therapy may be necessary.

7. IT'S ACCIDENT PRONE.

According to the American Association for the Surgery of Trauma, about 8 to 9 percent of blunt trauma includes pelvic injury, Gillogley says. "These accidents include falls, motor vehicle crashes, bicycle accidents, and pedestrians being struck by moving vehicles. With these serious injuries, pelvic bones can fracture or dislocate and sometimes bladder injury even occurs." So take care with your pelvis—in worse-case scenarios, breaks of the pelvic bones can require pins, rods, and surgery to fix.

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