15 Interesting Facts About Your Digestive System

Your Digestive System Is Surprisingly Long

The length of your entire digestive system from the mouth to the anus is approximately 30 feet long.

Your digestive system is responsible for breaking down the foods you eat so that you can absorb vital nutrients. Food is broken down mechanically—through chewing and the use of enzymes—into the form of molecules that can be absorbed by and moved through your blood. Your digestive system is made up of the following organs:

• Mouth
• Esophagus
• Stomach
• Liver
• Gallbladder
• Biliary Tract
• Small Intestine
• Large Intestine

You Produce a Lot of Saliva

Our mouths secrete approximately one liter of saliva a day.

Saliva production through our salivary glands is the first step in digestion. Food breakdown begins in our mouths through chewing, and the enzymes present in saliva.

Saliva is predominantly water but does contain other substances. It can be stimulated by thinking about or smelling food.

Saliva has many vital functions:

• Lubricates food for easy passage into the esophagus
• Coats food to protect our teeth and the lining of our mouth and esophagus.
• Increases in saliva before vomiting help protect teeth's enamel from stomach acid.

Swallowing Is a Pretty Complex Operation

Food takes two to five seconds to make its way down your esophagus into your stomach.

After we've chewed our food, it's formed into a bolus (a small, round mass). Swallowing is a complex procedure in which the bolus is moved into the pharynx as the larynx (the organ connected to our windpipe) is covered, and the esophagus opening is widened to accept it. The bolus is then moved down through the esophagus through coordinated muscle movements known as peristalsis.

The esophagus is bound on each end by a sphincter muscle responsible for an opening to allow the bolus to pass through. Heartburn can occur when the lower esophageal sphincter fails to close completely, allowing stomach acid to travel upward and irritate the tissue in the esophagus and throat.

Your Stomach Produces Hydrochloric Acid

It's the same stuff that masons use to clean bricks.

Luckily, our stomachs are lined by a thick layer of mucus to protect us from the acid and the enzyme pepsin it produces. The stomach's mixing motion, along with the acid and the breakdown of protein by the pepsin, turns the bolus into a liquid substance called chyme, which is then slowly released into the small intestine. For a full meal, this process takes approximately two to three hours.

Your Pancreas and Liver Are Not So Mysterious

The primary role of both your pancreas and liver is to produce substances that break down the foods you eat.

As the chyme enters your small intestine, it's met with juices produced by the liver and the pancreas. The liver produces bile, stored in the gallbladder, and then released into the small intestine to break down fats, while the pancreas secretes enzymes into the small intestine that break down protein, carbohydrates, and fats. The pancreas also releases bicarbonate, which neutralizes any acid that's made its way out of the stomach.

So Much Happens in Your Small Intestine

Your small intestine is where almost all of the absorption of nutrients from the foods we eat takes place.

The small intestine is where the most critical work of digestion takes place, that is, further breaking down the food we eat into molecular components that can be absorbed into the bloodstream. The small intestine has three parts:

• The duodenum
• the jejunum
• The ileum

Bile from the gallbladder and digestive enzymes from the pancreas are mixed into the chyme in the duodenum. The final breakdown and absorption of nutrients occur in the second two parts.

Fiber Is Very Important

Fiber is what is left over when all the other parts of food have been digested.

Once the small intestine has completed its breakdown of food and absorption of nutrients, it propels the undigested parts of plant food, known as fiber, into the large intestine.

Fiber is classified into two general types: soluble, which dissolves in water, and insoluble, which does not. Fiber both softens and bulks up the stool and affects the health of your gut bacteria, which play a role in supporting your immune system. Thus, dietary fiber is essential for both digestive and overall health.

How Much You Drink Affects the Look and Texture of Stool

Your colon, known as your large intestine, is a long, hollow organ typically about 5 feet long. It consists of the ascending colon, the transverse colon, the descending colon, the sigmoid colon, and the rectum.

Along with fiber, the small intestine propels liquid into the large intestine, where it's absorbed and stools are formed. Your large intestine receives about one quart of liquid daily from the small intestine.

Drinking adequate amounts of water helps to keep your stool soft and, therefore, contributes to a comfortable bowel movement. When you don't drink enough water, water is drawn out of the fecal matter within your colon, resulting in hard, difficult-to-pass stools.

Although there's great variation in frequency, stool is generally moved into the rectum once or twice a day in preparation for a bowel movement.

There Are Trillions of Bacteria in Your Digestive System

Your GI system plays host to more than 500 species of bacteria.

We are not born with any bacteria in our digestive systems but develop a significant population within the first month, most of which can be found in our large intestine.

Small intestine bacterial overgrowth (SIBO) is a health condition in which too many bacteria are present in the small intestine. SIBO has been theorized as a possible factor in the development of irritable bowel syndrome (IBS) in some individuals.

Your Body Actually Has Two Brains

Your brain and digestive system work in close partnership. You have first-hand knowledge of this any time your stomach flips when you think of something anxiety-provoking—or, more dramatically, if you experience diarrhea when you are stressed.

This collaboration is thought to be essential to our survival as a species; although digestion is essential for life, dealing with threats is just as necessary.

The body developed the "flight or fight" system to divert resources from the digestive system to the systems needed to fight off or run away from things that might harm us.

The Stomach Can Hold Up to 4 Pounds of Food at One Time

The capacity of the human stomach to stretch is remarkable. The average stomach holds up to 4 pounds of food, which would be quite uncomfortable. But some people's stomachs can hold even more; the world record holder for most hot dogs eaten, Joey Chestnut, consumed an astonishing 16 pounds of hot dogs.

Burping Is Your Body's Way of Pushing Out Excess Air

Burping (also called belching) is the release of air from your stomach. It is most common during eating and just afterward but can occur anytime. The average person burps 30 times per day!

The air your burp comes from air you swallow, fizzy drinks, eating quickly, chewing gum or sucking on candy, and even wearing loose dentures.

You Can Survive Without a Stomach

People with certain types of stomach cancer might need to have their entire stomach removed. People with a rare genetic predisposition to cancer might have their stomach removed before any cancer is diagnosed because the risk of cancer is so high, and by the time symptoms or testing can detect cancer, it is already advanced.

A gastrectomy involves removing the stomach, and the esophagus is attached directly to the small intestine. People without stomachs can still eat, but they must eat very small amounts of food. They must also eat many times throughout the day to obtain the proper number of calories.

Farts That Contain Hydrogen Sulfide Smell Bad

The vast majority of farts are odorless. Some farts–some put the number at around 1%–do smell. The gasses that cause the smell vary somewhat, but most smelly farts contain hydrogen sulfide.

Hydrogen sulfide is a gas that causes most of the smell in farts. It tends to smell like rotten eggs. Other gases that can contribute to odor are methane, nitrogen, and carbon dioxide.

The Digestive Systems Shares Similarities With Laundry Detergent

Digestive enzymes include lipase, protease, amylase, and others. These enzymes work to break down proteins, carbohydrates, and fat in food. This occurs in the small intestine, where the nutrients are absorbed.

Many of these same enzymes are used in laundry detergent, too—the enzymes in laundry detergent work very similarly to the enzymes in your small intestine. Stains on clothing may be made up of proteins, starches, and fats, and the enzymes in detergent break down these components so they can be washed away.