ABCs of the Digestive System

Discover how the digestive system works, the role certain organs play, the gut-brain connection, the interaction between gut health and anxiety, and much more. 

When you think about how the digestive system works, you might think of your stomach first. After all, you get hungry, you eat—and the food ends up in your stomach. And the stomach is, indeed, a vital part of the system in your body that turns food into the energy you need to function. But, the digestive system is much more complex, and we’ll use an excellent Cleveland Clinic article to walk you through the parts of this system. 

How the Digestive System Works

The process of digestion starts with your mouth. As you bite into food and chew it, you’re breaking the food you eat into easier-to-digest pieces. While the food is in your mouth, saliva starts to break it down further, helping to create a form of food that’s absorbable and usable. The food then travels down your esophagus. This part of your body uses a process called peristalsis, a series of contraction of muscles, to move the food from your mouth to your stomach.

Once the food arrives inside this hollow container, the cells from your stomach lining supply enzymes needed to continue to break down what you ate. And, here’s a miracle that occurs every day, without our ever being aware of it: your stomach knows when its work is done, knowing when to move what it broke down into your small intestine.

People don’t always think about the small intestine, but it plays a significant role in the digestive system. This 22-foot-long organ consists of three segments:

  • duodenum
  • jejunum
  • ileum

As food enters the small intestine, this muscular organ continues to break it down, using pancreatic enzymes and liver bile. The role of the pancreas is to break down protein, carbohydrates and fats, and to metabolize sugar through the use of insulin. The liver processes nutrients from the small intestine, digests fat and more, including doing detox work on any chemicals with potential for harm.

The duodenum, with the help of the gallbladder, plays the largest small-intestine role in breaking down food. Then, the other two parts help the body to absorb food nutrients into the bloodstream, with the remaining material moving to the colon, also called the large intestine. The colon is six feet in length, also a muscular organ with multiple parts:

  • ascending colon (right side)
  • transverse colon (across the body)
  • descending colon (left side)
  • sigmoid colon (connects to your body’s rectum)

The role of this organ is to process waste so it can be easily removed from your body. The large intestine first receives liquid waste from the small intestine and, through the process of peristalsis, removes the water. This creates solid waste that is stored in the sigmoid area, then forwarded to the rectum one or two times daily. More formal names for this waste include feces or stool. In common lingo, we call it poop.

Once the stool is in the rectum, you might begin to feel the urge to poop. The rectum is an eight-inch chamber that, when containing stool, sends messages to the brain so that contents can be emptied by sphincters relaxing and your rectum contracting. The far end of the digestive system is the anus, about two inches in length and containing internal and external sphincters, plus pelvic floor muscles. The top of this organ detects when poop is in the rectum; the pelvic floor muscles keeps the poop in the body when you want to keep it there. The external sphincter keeps the stool in place until a person reaches a toilet and is ready to poop.

Gut-Brain Connection

Intriguing research is taking place on the subject of the gut-brain connection, with experts at the cutting-edge John Hopkins Medicine site sharing insights. Here’s a quote from an article titled The Brain-Gut Connection: “If you’ve ever ‘gone with your gut’ to make a decision or felt ‘butterflies in your stomach’ when nervous, you’re likely getting signals from an unexpected source: your second brain. Hidden in the walls of the digestive system, this ‘brain in your gut’ is revolutionizing medicine’s understanding of the links between digestion, mood, health and even the way you think.”  

Fascinating, isn’t it?

What the quote is calling your “second brain” is what scientists have named the enteric nervous system (ENS). Within the ENS are more than 100 million nerve cells (yes, more than 100 million) that line your body from your esophagus to your rectum. The article points out how this brain “can’t balance your checkbook or compose a love note.” But, what it can do is incredible: the ENS controls your digestive system and communicates with the brain found inside our skulls “with profound results.”

And, here’s where revolutionary thought comes in. ENS may actually be responsible for the “big emotional shifts” that people with digestive problems deal with, conditions ranging from irritable bowel syndrome to general bloating, pain, constipation, diarrhea and overall stomach upset. For decades, doctors and researchers blamed the emotional upset, including anxiety and depression, on the bowel symptoms—but, in fact, the reality may be the other way around. Gastrointestinal irritation may send signals to our central nervous systems that serve as mood triggers.

Research suggests that activity going on in your digestive system may affect your ability to think as well as your memory. John Hopkins hopes to delve further into that research.

Digestive System Problems

The number of people who suffer from digestive system problems in our country alone is incredible. According to the National Institutes of Health of Diabetes and Digestive and Kidney Diseases, there are 60 to 70 million people in the United States with some form of a digestive disease. In 21.7 million cases, someone was hospitalized because of digestive system problems, with 245,921 people dying of one in 2009 alone.Using 2004 as a sample year, the NIH recorded $141.8 billion in direct and indirect costs associated with digestive health issues.

Gut Health Strategies

If you’ve already been diagnosed with digestive system problems or have troubling symptoms, it’s important to get quality medical care. If you’re looking for tips about ways to be kind to your digestive system with the goal of improving health, we’ll offer some.

First, if your grandmother told you to slow down and do a better job of chewing and swallowing your food, Grandma was right. The more you break down your food early in the digestion process, the less work your body must do as it goes through the system. If you eat quickly, practice eating more slowly, because this also gives your brain time to receive and send appropriate signals that allow you to recognize when you’re full.

Fiber is important, too, the kind you get from eating fresh fruits and vegetables, and whole grains. It’s also important to drink enough water; too little makes your stool harder and more difficult to eliminate. Exercise regularly and either stay or get to a healthy weight.

Evaluate your habits. If you smoke, the best thing you can do for your body, including your digestive system, is to quit. LImit alcohol consumption and, if you do either of these as a reaction to stress, find healthy ways to deal with stress. And, if you don’t need to address either of these habits, stress reduction techniques will still help your gut health.

We’ll explore the interaction between gut health and anxiety next, followed by recommendations to manage that stress. 

Gut Health and Anxiety

According to a 2017 article in, “stress may be just as detrimental to our health as junk food—for women, at least.” That’s because stress, research indicates, impacts our gut microbiota as much as a diet high in fat. And, we live in a country where stress is high, with the American Psychological Association estimating that about 80 percent of people in the United States experienced one or more stress symptoms in past 30 days, according to self-reporting.

To help, the Canadian Society of Intestinal Research shares tips on managing stress, with the goal being better gut health. They note that stress doesn’t look and act the same from person to person, and so different stress management techniques will work for different people. For some, pre-planning life events to the degree that’s possible can help, as can incorporating time management techniques that keep them from running late. In general, when you give yourself 20 percent more time than you think you need will provide a comfortable cushion.  

Tips that work for many (maybe even most) people include breathing more deeply and slowly, perhaps by imagining you need to inflate then deflate a small beach ball located behind your belly button. Try to avoid negative self-talk and/or making mountains out of molehills. In general, monitor the degree and substance of your negative thoughts. If you keep returning to a negative thought, try replacing it with something more positive.  

Take time for just you, whether that involves going on a walk, reading a book that caught your eye, listening to music, throwing a ball for your dog, chatting with friends or something different entirely. Connected to this tip is learning to politely yet firmly say “no” when your schedule is already full enough.  

Eating a quality diet helps and so does a “good belly laugh. Laughter is a natural stress reliever that helps to lower blood pressure, slow your heart and breathing rate, and relax your muscles. How do you tickle your funny bone? Catch comedies, have a chuckle with a friend, and make an effort to look on the lighter side of life.” 

Health Benefits of Probiotics 

We created an in-depth blog post about the benefits of probiotics, and here is a bullet-point summary from that post that shares the health benefits of probiotics:

Probiotics are believed to:

  • absorb or destroy byproducts of bad bacteria that contributes to illness
  • create infection-preventing substances
  • block harmful bacteria from connecting to your digestive wall and staying there
  • boost immune systems
  • strengthen intestinal mucus to perform as a barrier against infection
  • produce helpful B vitamins
  • decrease the production of gas and, therefore, bloating

You can get probiotics in your diet through consuming certain foods, including cultured dairy products, such as yogurt; fermented dairy, such as kefir; fermented veggies, including sauerkraut; fermented beverages and those with soy, and more. You can also take probiotic supplements.  

About Roger & Jane Hardy

Roger and Jane created Hardy Healthy Gut to show you that every problem in life is easier to solve when your mind and body are working properly.
And you don't have to be a health nut or fitness enthusiast to enjoy a mind & body that's firing on all cylinders.

All it takes are simple, daily habits that get easier and easier with practice.

The tips we teach are the same simple daily habits that helped us feel better in our 40's than we did in our 20's.
And these same daily habits have made our 50's and 60's a successful adventure!

Now we look forward to the future and we're enjoying getting older!

Which proves that age is just a number and that number isn't what's slowing you down.
Your age isn't the real cause of those aches, pains, and brain fog.

All of this is possible for you too, my friend!

So thank you for being here. I hope you use these tips to transform your life and enjoy retirement as much as we have!

Click here to learn more about how Roger can help you boost your success

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