One of the most interesting and intriguing bodily systems is our digestive tract. When it runs smoothly with no problems, we tend to forget how important and vital this system is to our health:
However, when things go wrong, it gets our attention right away. Suddenly we realize just how little we may actually know about our diverse and dynamic digestive tract.
Here is a look at 8 facts you may not have known about this fascinating system:
1. From mouth to anus, our digestive system is approximately 30 feet long
Take a tape measure and find out visually how long 30 feet is. Now imagine that is the length of what is wrapped up inside our body and the distance our food has to travel from beginning to end.
The purpose of our digestive system is to digest and absorb. To digest means to break down our food into the smallest components possible. To absorb means to take in within our body to nourish it.
The beginning of our digestive system starts with our mouth as we take a bite of food. Once we swallow, it now enters the esophagus. At the end of the esophagus is an opening into our stomach. The stomach churns to break down the food further before it is ready to enter the approximately 22-foot length of the small intestine which is the major site of digestion and absorption.
Whatever is still left at the end of the small intestine will transfer into the 5-foot length of the large intestine or colon. Inside the colon, our bowel movements are formed which leave the body through the anus, which is the end of our digestive system.
2. We make one liter of saliva a day
One of the first steps of digestion is the production of saliva from the salivary glands. Amazingly, each day we produce about one liter or 4.2 cups of saliva.
Just thinking, smelling, or anticipating eating food can get our salivary juices flowing. Water is the predominant ingredient along with other substances such as enzymes.
These enzymes found in saliva are responsible for food breakdown which is also aided by chewing. Adequate saliva is necessary for lubricating our food so we can easily swallow it without pain plus it also coats food protecting our teeth and the lining of our mouth and esophagus.
3. Your food doesn’t require gravity to reach your stomach
Whether you are standing up or hanging upside down, your esophagus has the ability and muscles to send your food towards the direction it needs to go – your stomach.
What propels food from the throat down the 8-inch length of the esophagus are muscles that contract to move food to the stomach. This process is called peristalsis.:
Peristalsis moves the swallowed food in wavelike contractions from the top portion of the esophagus (upper esophageal sphincter) to the bottom portion (lower esophageal sphincter), slightly above the opening to the stomach.
4. Hydrochloric acid is made by our stomach
Exactly how strong is stomach acid? Acids are measured on a scale known as the pH scale which goes from 0 to 14, with – being the most acidic, 7 being neutral, and 14 being the most alkaline or basic (non-acidic).
Stomach or hydrochloric acid is very acidic, with pH measurements ranging from 1 to 3 putting stomach acid in the same approximate category as battery acid. What prevents this powerful acid from eating a hole right through? Luckily our stomachs are lined by a thick layer of mucus to protect us from the acid and the enzyme pepsin that it produces.
When food enters the stomach, the mixing motion of this organ along with the acid turns our food into a liquid substance called chime, which is slowly released a little at a time into the small intestine. This process will take approximately 2-3 hours for a full meal.
5. How our stools look depend on how much we fluid we drink
Every day about one quart of liquid leaves the small intestine and enters into the large intestine. Along with the deluge of fluid, undigested fiber passes from the small intestine into the large intestine.
This fluid will be absorbed helping the formation of our stools. To keep our stools soft and easy to pass, it is important to drink adequate fluid (preferably mostly water) daily.
Not drinking enough fluid results in water being drawn out of the fecal matter in the colon resulting in a small, hard, and difficult-to-pass stool, better known as constipation.
6. Your stomach doesn’t do most of the digestion
If you had the belief most of your digestion of food occurs in the stomach, think again. Your stomach does play a role in “mechanical digestion “ – it churns food, and mixes it with gastric juices, physically breaking up food bits and turning them into a thick paste called chyme.
But the chemical digestion, the process that reduces food to the size of molecules necessary for nutrients to be taken up into the bloodstream, actually occurs in the small intestine. Two-thirds of the length of the digestive tract is made up of the small intestine, the major site where most digestion and absorption of nutrients takes place.
7. The surface area of the small intestine is huge
The small intestine is about 22 feet (7 meters) long, and about an inch (2.5 centimeters) in diameter. Based on these measurements, you’d expect the surface area of the small intestine to be about 6 square feet – but it’s actually around 2,700 square feet or about the size of a tennis court:
That’s because the small intestine has three features that increase its surface area. The walls of the small intestine have folds, and also contain structures called villi, which are fingerlike projections of absorptive tissue. What’s more, the villi are covered with microscopic projections called microvilli. All of these features help the small intestine to absorb food better.
8. The digestive system is prone to developing cancer
Each year, more than 270,000 Americans develop a cancer of the gastrointestinal tract, including cancers of the esophagus, stomach, colon, and rectum. About half of these cancer result in death. What’s more, the digestive system is home to more cancers, and causes more cancer mortalities than any other organ system in the body.