How Your Digestive System Works

How the digestive system works

The Western diet and lifestyle is linked to a growing number of Americans that are affected by digestive diseases. The health of your digestive system has a lot to do with lifestyle, for it’s determined by the food you eat, the amount of exercise you get and your stress level throughout your day.

By understanding the digestive process and learning about some helpful tips, however, you will be able to not only diagnose but treat your own digestive issue.

The digestive system is a group of organs that work together to convert food into energy and basic nutrients that feed the entire body; it’s the foundation of good health. This amazing system includes a combination of nerves, hormones, bacteria, blood and the organs of the digestive system that work together to complete the intricate task of digesting the foods and liquids that we consume every day.

The digestive system interacts with all other body systems — this includes the nervous, endocrine and immune system. Did you know that digestion actually begins in the brain? The hypothalamus, which is involved in metabolic processes, stimulates appetite. When you eat, your brain decides how you will digest that food – it will respond with stress or ease, depending on the health of your organs and your state of mind.

There are a number of factors at play in the digestive system. We have digestive juices that contain enzymes that speed up the chemical reactions in the body and break down food into nutrients. There are also cells in the lining of the stomach and small intestine; these cells produce and release hormones that stimulate digestive juices and regulate our appetite.

We also have nerves that control the digestive system. They connect our digestive organs to the brain and spinal cord as well as release chemicals that stimulate relaxing or contracting muscles. We have nerves within the GI tract that are triggered when there is food present, and this allows our digestive system to work properly.


Western vs. Eastern Medicine — the Spleen in Traditional Chinese Medicine

In Western medicine, the spleen is recognized for its production and destruction of red blood cells and storage of blood. However, in traditional Chinese physiology, the spleen takes a lead role in the assimilation of nutrients and maintenance of physical strength. It turns digested food from the stomach into usable nutrients and qi, which is our life energy force.

In China, entire schools of medicine were formed around this organ because it’s believed that all aspects of life depend on the functioning of this essential organ, which allows the body to receive its needed nutrients.

In Eastern medicine, fatigue and anemia are often recognized as a breakdown in the spleen’s ability to transform food into blood and energy. If the spleen is weak, then the colon, uterus, rectum or stomach can sag or weaken. According to the ideas of Eastern medicine, exercise and a healthy diet can benefit the body only if the spleen is able to transmit nutrition and energy to the muscles, and a person with deficient spleen function will often experience weakness and fatigue.

In addition to its role in nutrition and blood production, the spleen is viewed as being responsible for the transformation of fluids, as it assists in water metabolism, helping the body rid itself of excess fluid and moistening the areas that need it, such as the joints. It separates usable and unusable fluids that we consume daily.

The spleen has the power to transform food and liquids into energy, which is then transported to our organs and enables the proper function of our entire body – this is why the spleen is seen as playing a central role in nourishing our bodies and promoting development.

The spleen and the stomach work together and ensure the other’s functions. Because the spleen is where the energy of food and fluid is transformed, it’s the most essential of the pair.

In traditional Chinese medicine, the spleen is considered essential for healing because it not only affects the body’s immunity but also the ability to maintain and heal itself. It’s also believed that the spleen influences our capacity for thinking, focusing, concentrating and memorizing.


The Role of Specific Organs

Role of organs in digestive system

Mouth – The simple act of chewing breaks food into pieces that are more easily digested, and saliva mixes with the food to begin the process of breaking it down into a form that our body can absorb and use. When you swallow, your food pushes into the esophagus, the muscular tube that carries food and liquids from the mouth to the stomach. Once swallowing begins, it becomes involuntary and proceeds under the control of the esophagus and brain. (1)

Spleen – The spleen is a brown, flat, oval-shaped lymphatic organ that filters and stores blood to protect the body from infections and blood loss. It helps fight infection and keep body fluids in balance. The spleen is in charge of cleaning impurities from the blood, destroying old red blood cells and storing blood in case of emergency, such as an injury.

Stomach – The stomach acts as a storage tank for food so that the body has time to digest large meals properly. This central organ not only holds the food, it also works as a mixer and grinder. The stomach contains hydrochloric acid and digestive enzymes that continue the digestion of food that began in the mouth.

Enzymes and acids mix with the food that has already begun to break down in the mouth and esophagus, and it turns into a liquid called chyme. The word chyme comes from the Greek meaning of juice; it’s a semi-fluid mass that is expelled by the stomach and sent to the intestines during digestion. In the stomach, hydrochloric acid destroys harmful bacteria and alters enzymes to begin digesting protein. (2)

Hydrochloric acid is a clear, colorless and highly pungent solution of hydrogen chloride in water. It’s a corrosive mineral acid that serves as a digestive fluid and breaks down unwanted bacteria. After it does its job, our food is the consistency of a liquid or paste, and it’s ready to move to the small intestine for the next step of this complex system.

Liver – The liver is the second largest organ in the body, and it has many different functions. But the main function of the liver in digestion is the production of bile and its release into the small intestine. The liver makes and secretes bile, which helps enzymes in the body to break down fats into fatty acids. The liver also cleanses and purifies the blood that is coming from the small intestine.

After we absorb nutrients through our small intestines, it then enters the bloodstream. This blood is sent to the liver for filtering and detoxification. The liver has the amazing ability to break down and store amino acids, synthesize and metabolize fats and cholesterol, store glucose, detoxify the blood and regulate our internal functions. (3)

Gallbladder – The gallbladder is a small, pear-shaped organ that is used to store and recycle excess bile from the small intestine so that it can be reused for the digestion of future meals. The gallbladder sits just under the liver and stores bile that is made in the liver, which then travels to the gallbladder through a channel called the cystic duct. The gallbladder stores bile between meals, and when we eat, the gallbladder squeezes bile through the bile ducts, which connect the gallbladder and liver to the small intestine.

 Pancreas – The pancreas is a spongy, tube-shaped organ that is about six inches long. It secretes digestive enzymes into the small intestine, and this completes the chemical digestion of foods. Pancreatic juice is capable of digesting lipids, carbohydrates (creating energy), proteins (creating amino acids for building) and nucleic acids. Insulin is one of the hormones made by the pancreas; insulin controls the amount of sugar in the blood. Both enzymes and hormones are needed to keep the body and digestive system working properly.

The pancreas connects to the liver and the gallbladder with the common bile duct. As pancreatic juices are made, they flow into the main pancreatic duct, and then join the common duct – which allows the bile (which helps to digest fat) break down food before it reaches the small intestine.

Small Intestine – The small intestine is a long, thin tube that about one inch in diameter and about 20 feet long. When the chyme (our juices that are being digested) leaves the stomach, it enters the small intestine through the pyloric sphincter – a muscle that serves as a valve and prevents the regurgitation of food from the intestine back into the stomach.

The entire small intestine is coiled and the inside surface is full of many folds and ridges; most of the digestion and nutrient absorption occurs in the small intestine. It transforms from an acidic environment to an alkaline one, which means that the acids are neutralized.

The small intestine is lined with very small protrusions that increase the surface area of the intestinal wall, which creates a larger absorption area. Each protrusion, called villi, is covered in smaller hair-like structures, which are called microvilli. Enzymes exist on the villi, helping further break down nutrients into a readily absorbable form. It is the job of the villi that help prevent leaky gut.

Leaky gut is when the bowel lining is damaged. This is caused by poor diet, parasites, infection or medications, and it allows substances — such as toxins, microbes, undigested food or waste — to leak through the small intestine. (4)

The folds in the small intestine are used to maximize the digestion of food and the absorption of nutrients. By the time food leaves the small intestine, around 90 percent of all nutrients have been extracted from the food that entered it. Once the nutrients have been absorbed, the liquid that is left over passes through the small intestine and goes to the large intestine, or colon.

Colon – The colon, or large intestine, is a long, thick tube that is about two-and-one-half inches in diameter and five feet long; it wraps around the border of the small intestine. Once the juices (that used to be your food) leave your small intestine, they enter your large intestine. At this point, most of the nutrient absorption has happened, but water, fat soluble vitamins and minerals can be absorbed in the colon as well.

The naturally present bacteria that are present in your colon will continue to help with digestion; these gut bacteria are called flora. Flora breaks down wastes and extracts small amounts of nutrients (whatever is left). The waste that is left over will exit the body from the colon by means of peristalsis, which are contractions that move the waste to the anal canal. At first the waste is in a liquid state, but as it moves through the colon, the water is removed and it becomes the solid form of stool.

The stool is mostly food debris and bacteria; the bacteria fuse vitamins, process waste and food particles, and protect us against harmful bacteria. It takes about 36 hours for stool to get through the colon, and when the colon becomes full, it empties its contents into the rectum, which begins the elimination process.


10 Healthy Tips to Improve Your Digestive System 

The way we live and eat has a direct impact on our digestive system and how well it functions. By taking steps to improve your digestive health, your digestive system will function more efficiently, and this will improve your overall health.

  1. Keep chewing – An easy tip that can have a huge impact on your digestive system is the simple act of chewing! Chewing is often underestimated, but it’s crucial for proper digestion. The more you break down food in your mouth, the less work has to be done later. Your brain also needs some time to receive the signal that you are full, so take your time and chew eat time 20–30 times before swallowing. Allow your stomach to prepare for the food it’s about to receive.
  1. Eat plenty of fiber – It is important that you eat enough fiber to keep your food moving through your intestines easily. There are two types of fiber – soluble and insoluble. Soluble fiber, like veggies and whole grains, draws in water and helps to prevent stool from being too watery. Insoluble fiber helps to add bulk to stool. By pairing fatty foods with fiber, your body will be able to break down the fatty foods (which are usually hard to digestive) easily. (5)
  1. Drink water – Adding plenty of water to your diet will help digestion by dissolving fats and soluble fiber – this allows food to pass through your intestines more easily. This is a simple tip that will have a big impact; too little water will lead to a harder stool that is more difficult to pass through the colon.
  1. Exercise – Moving your body – taking walks or jogs, lifting weights or doing yoga – keeps food moving through your digestive system. Exercise increases blood flow to your organs and engages muscles in the GI tract; this is important because the walls of your colon need to contract when passing waste, and exercise can tone those muscles.
  1. Reduce stress – Feelings of stress or anxiety can mess with your digestive system because your brain and digestive system are connected. Stress can lead to digestive problems like irritable bowel syndrome and ulcers. To help control these digestive health issues, try stress-relieving exercises, getting more sleep or relaxation techniques like steady breathing or meditation and prayer. (6)
    Digestive system tips
  1. Eat warm foods – The spleen works best with the warmth and dislikes the cold, and our digestive enzymes require warmth to break down food properly. Too much cold food and drinks can impair our spleen function, so eating foods that are warm are easier to digest. Try incorporating soups, cooked vegetables or teas into your diet.
  2. Quit smoking – Smoking can have a seriously negative impact on your digestive system because it weakens the valve at the end of the esophagus, and this leads to acid reflux and heartburn; it also increases the risk of gastrointestinal cancers.
  3. Drink less alcohol – Ever notice how your digestion is a little off after a night of drinking? Alcohol interferes with acid secretion, stomach muscles and nutrient absorption, so be careful not to drink too much. Alcohol consumption also leads to heartburn, liver problems and diarrhea; it can wreak havoc on organ function and the success of your digestive system. (7)
  4. Lose weight — Being even a few pounds over weight can cause digestive issues; for instance, the valve between the stomach and esophagus sometimes won’t close completely, which allows stomach acid back into the esophagus. By losing weight, you are easing pressure and allowing your digestive system to carry on properly.
  5. Try probiotics — Besides fiber, one of the things missing from the Western diet is healthy doses of probiotics, which are beneficial bacteria that help the immune system. Probiotics compete for space with bad bacteria, promote the release of natural antibodies in the digestive tract and can even attack unhealthy bacteria directly in some cases. Research has found that probiotics can ease irritable bowel syndrome, prevent allergies and infections, and even shorten the duration of the common cold. Cultured dairy is one of the best sources of probiotics; you can also try sourdough bread, pickled cabbage and fermented soybeans. (8)

 Read Next: Should You Do an Elimination Diet?

Josh Axe

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