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Did the thought ever cross your mind about how the food you take is absorbed and converted into energy? The digestive system serves multiple roles: taking, absorbing, and using the essential nutrients—vitamins and minerals—we take in, and, of course, eliminating waste.

The digestive system includes the mouth, esophagus, stomach, liver, gallbladder, biliary tract, small intestine, and large intestine. It involves the integrated coordination of these organs in the digestive process when you eat or drink, or even when you abstain from it.

While you may not think about your digestive system often (until you get a stomach upset!), the reality is that you use it all the time.

10 Fascinating Facts About the Digestive System

It would be interesting to look at some fascinating facts about your digestive system you may not have known.

How Much Saliva You Produce Daily?

The average person produces 2 pints of saliva every day; that is 32 ounces or 2 cans of soda. This clear substance, made up mostly of water, blends with food to help even the driest snack, slide smoothly down into your stomach. Before those bites hit your belly, some special enzymes in the saliva called amylase and lipases break down that food into softer components to digest the morsel better.

The amount of saliva you produce increases when you throw up to protect your teeth from the hydrochloric acid in your stomach that will come up.

Does Gravity Affect the Food to Swallow?

No, it does not connect the process of swallowing to gravity because it works with muscular activity. In fact, your body can move your food through the digestive system even if you are standing on your head. Though it could be difficult to eat in an upside-down position, it’s possible.

Food can be swallowed even if you stand upside down but can get choked

Your esophagus has giant wavelike muscles that help food or drinks slide down to your stomach. This wave action is called peristalsis. However, overstuffing food in your mouth can disrupt this activity and lead to choking. It takes 5 to 7 seconds for the food to travel down the esophagus into the stomach. So, swallow or gulp slowly to make the system work smoothly.

Digestive Enzymes are like Laundry Detergents

Like laundry detergent, enzymes in your digestive system separate the food into different nutrients that your body needs. It is secreted by your salivary gland and then by the stomach, pancreas, and small and large intestines. The classification of these digestive enzymes is based on their respective substrates. Proteases break down proteins, amylases break down carbohydrates, and lipases break down fats.

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For example, enzymes produced in the mouth use amylases and lipases, which help break down large starch molecules into smaller sugar molecules. The stomach enzymes use proteases to split proteins into smaller peptides and amino acids. Pancreatic enzymes are critical to efficient digestion. This complex network and coordination of enzymes help in the segregation of nutrients and proper digestion.

The Gut-Brain Axis

The gut-brain axis is the close partnership that exists between the gastrointestinal tract (GI tract) and the enteric nervous system (ENS). The mouth, esophagus, stomach, small intestines, large intestines, and anus form the GI tract. It is also known as the alimentary canal or the digestive tract. The ENS consists of a huge number of nerve cells and is regulated by the same neurotransmitters, most notably serotonin, found in the brain.

What does your gut-brain do? The gut connects with the brain through chemicals like hormones and neurotransmitters that send first-hand knowledge of your stomach condition to the brain. Emotions (including stress, anxiety, and anger) and brain disorders can directly affect how your body digests food.

Dysfunction in the gut-brain coordination is believed to play a critical role in the development of functional gastrointestinal disorders (FGDs).

Is Small Intestine Actually Small?

Small intestine is longer than the large intestine

The length of a small intestine is about 22-23 feet and about an inch in diameter. Based on these measurements, you’d expect the surface area of the small intestine to be approximately 2,700 square feet (250 sq.m), or about the size of a tennis court. Whereas, the large intestine is only about 5 feet long.

Looks are deceptive, so are some names, eh?!

So, what does the small intestine do?

It absorbs most of the nutrients from what you eat and drink, which is vital for your health. Though mechanical digestion happens in the stomach, the small intestine does most of the digestive work.

Large Intestine Helps in Bowel Movement

Your large intestine, otherwise known as the colon, is a long, hollow organ, typically about five feet long. It turns liquid waste into a solid stool and is also responsible for absorbing the remaining nutrients and water that your body needs. The large intestine gets about 32 ounces of liquid a day from the small intestine. Besides fiber, the small intestine propels liquid into your large intestine. This gets absorbed, and it forms stools.

Your large intestine ensures you don’t lose too much water during the digestion process. But when you don’t drink sufficient water, it draws out the excretory matter within your colon, resulting in hard, difficult-to-pass stools. So, drinking adequate amounts of water can help to keep your stool soft, thus contributing to a comfortable bowel movement.

Keep Fit for Better Digestion

Regular exercises can help in better digestion

Aerobic exercise is the best type of exercise to keep your digestive tract in shape. Cardiovascular conditioning can be improved by activities like brisk walking, swimming, running, or cycling.

What do exercises have to do with digestion? Regular cardiovascular exercise helps strengthen ab muscles. When your heart rate is elevated regularly, it helps to reduce intestinal sluggishness. It stimulates your muscles to push digestive waste through your body. Breathing exercise can improve blood circulation and help carry the nutrients derived from the digestive process more efficiently.

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Why Those Funny Sounds?

Stomach growling or rumbling is called borborygmi and is a normal part of digestion. It happens all the time, but it is more audible when your stomach is empty because there is no food to repress the sound. It can also sound when the stomach is full but because of incomplete digestion or indigestion. The stomach can stretch and hold food up to 4 pounds at a time. The best way to prevent stomach rumbling is to drink plenty of fluids and avoid hard-to-digest foods.

How does a hiccup occur? When your diaphragm muscle contracts repeatedly, the opening between your vocal cords snaps shut to lessen the inflow of air and releases a hic sound. To prevent a hiccup, gulp a glass of water.

Did you know the longest bout of constant hiccups lasted 68 years? OMG!

You burp (belch) to release extra air that you swallow if you eat fast, drink strong carbonated drinks, or smoke. Ever wonder why it smells bad when you pass gas? That is because a combination of swallowed air and gases produces it, such as methane and hydrogen sulfide, which are produced by the fermentation of bacteria in the large intestine.

Stomach has a Protective Coating

You may have heard of hydrochloric acid as a powerful chemical. Besides its several usages, it is commonly used to remove rust and scale from steel sheets and coils. Interestingly, the cells along the inner wall of the stomach secrete half a gallon of hydrochloric acid each day. This aids in digestion and helps kill bacteria.

To protect itself from the corrosive acid, the stomach has a layer of mucus. This prevents hydrochloric acid from causing acid erosion and breaking down the stomach. But this mucus cannot resist the digestive juices indefinitely. So the stomach produces an extra layer of mucus every two weeks to retain its strength and stability.

Role of Pancreas and Liver in Digestion

These 2 organs produce substances that break down the foods you eat. Chyme is a semi-fluid pulp formed in the stomach made of partially digested food and the secretions of the GI tract. As the Chyme passes into the small intestine, it gets mixed with fluids produced by the pancreas and the liver.

How do these 2 organs play their individual roles? The liver produces bile and stores it in the gallbladder, which is then released into the small intestine to break down the fat. The pancreas secretes enzymes into the small intestine that break down protein, carbohydrates, and fats.


Digestion is a six-step process. First, the food is ingested, chewed, and swallowed. Next, muscular contractions propel it through the alimentary canal and physically break it down into tiny particles. Then the digestive fluids chemically digest the nutrients from food into molecules small enough for absorption. Finally, indigestible substances are eliminated as waste.

A smooth flow from ingestion to elimination and the crucial processes in between depends on the condition of your alimentary canal. Any hurdle during the process can create digestive disorders, leading to pain, discomfort, and indigestion.

Understanding the specific role of each organ in your digestive system and the elements that can improve your digestion is the key to a good digestive system and a healthy life. This does not require medical degrees, but some good reading and keen observation of your body functions.

Editor’s Note: We updated this article on March 27, 2022 for accuracy reasons.

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