Get to Know Your Digestive System

Straight talk on all the twists and turns that take place in your tract.

You know your body's brilliantly designed to digest food; every time a morsel or a sip passes your lips, you set off a complicated machine that eventually transforms that little bit of deliciousness into the energy and cellular activity you need to survive. Ever wondered what exactly goes on between the table and, well, the toilet? We teamed up with Bayer Consumer Health, makers of MiraLAX, an over-the-counter laxative that works with the water in your system to ease, hydrate and soften to unblock your system naturally, to bring you this top-to-bottom tour of your digestive tract in motion.

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The Nibbler

Yes, the process begins at first bite. As you munch away, saliva mixes with the food in your mouth to help it first slide down the throat, and then to the esophagus. Fun fact: The mouth contains three pairs of larger salivary glands that produce about two pints (one liter) of spit each day!

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The Pipes

The esophagus's main job is to carry food, liquid, and saliva from your mouth to your stomach. It's an involuntary process that functions with the help of muscular layers called sphincters, which are located at the upper and lower ends of the esophagus. As soon as a beverage or bits of food enter this area, a series of contractions (called peristalsis) allow the muscles to relax so that the items can glide down to the belly.

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Your Inner Blender

This is where the real action begins! The super-muscular stomach has three jobs: storing swallowed food, grinding it into even smaller pieces courtesy of digestive juices that are made from acid and enzymes, and releasing the resulting liquidy paste into the small intestine. This paste is released into the small intestine in small quantities, while the rest stays in the stomach for extra blending before it makes its way down to the small intestine.

"What's interesting about the stomach is that this is where acid reflux — such a common problem — happens," says Nancy Simpkins, MD, a board certified internist. "Acidic foods, such as red sauce, can travel back up and 'burn' the esophagus." If eating less of the contributing foods and taking an antacid doesn't put out the fire, Dr. Simpkins suggests consulting your physician.

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Breakdown Central

Don't be fooled by its name — when the small intestine is stretched out, it's about 22 feet long. Food and drinks pass through three sections of the small intestine — the duodenum, jejunum, and ileum — before they head south to the colon. In fact, 90 percent of digestion and food absorption occurs in this long, narrow tube. "Basically, it's a workhorse that breaks things down and absorbs [most] of the nutrients from healthy foods," Dr. Simpkins says. There are very few diseases, she continues, that affect this fairly well-protected organ (with the exception of Crohn's disease, which can originate in the small intestine).

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Juicer

The pancreas, liver, and gallbladder work simultaneously with the small intestine by producing digestive juices. The pancreas distributes enzymes (for breaking down protein, fats, and carbs) and insulin (the hormone that helps your body use sugar). At the same time, the liver processes nutrients, metabolizes fat, and filters out chemicals that may be harmful to the body, while the gallbladder forces bile — which helps fat absorption — into the small intestine. Gallbladder conditions like gallstones are much more common in the female population, Dr. Simpkins says. They happen when the gallbladder needs to regularly work overtime to break down fatty foods.

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The Final Frontier

How's this for irony: The large intestine, a.k.a. the colon is three times shorter than the small intestine — it's about 6 feet long. It connects the small intestine to the rectum, and it's here that anything left over from the digestion process is turned into solid waste. When the system is working smoothly, an easy bowel movement will occur about 36 hours after this entire process began.

And when it's not...well, this is where some of the most common GI complaints occur. Constipation, for example, can leave you feeling bloated and "off." It's defined as pooping less than three times a week, with small stools that are difficult to pass and different from your normal pattern. "Garden-variety constipation — something that 60-70 percent of my female patients have at any given time — is usually diet-related," Dr. Simpkins says. For an occasional backup in the colon, consider drinking more water, eating fiber-rich foods, doing gentle exercises, or taking an over-the-counter remedy, like MiraLAX (which works with the water in your body to hydrate, ease and soften, unblocking your system naturally).

"The main thing that gastroenterologists and internists like about MiraLAX is that it's not a stimulant to the colon like many over-the-counter medications," she adds. "It pulls fluid into the bowel, but only the proper amount that your bowel needs to keep everything running at a normal rate." While occasional constipation is common, seek medical attention if you're plugged up for a week or more.

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