The digestive system is a group of organs that work together to change the food you eat into the energy and nutrients your body needs. After you consume food and liquids, the digestive system breaks them down into their basic parts: carbohydrates, proteins, fats, and vitamins. These basic nutrients are then absorbed into the bloodstream, which carries them to cells throughout the body. Nutrients provide the cells with the energy they need for growth and repair. Everything in your body, from your hormones to your heart, needs the nutrients from the digestive process to work correctly.
How it works
When you eat, food travels from the mouth down the esophagus to the stomach. Then it moves through the small and large intestines, and eventually out through the anus as waste. The liver, pancreas, and gallbladder are also included in the digestive system. These organs produce chemicals that allow digestion to occur.
All of these organs work in harmony to make sure the body receives the nutrients it needs. Some of the organs are hollow, while others are solid. A series of muscle contractions moves food through the digestive system from the hollow organs to the solid organs. This important process is called peristalsis.
The hollow organs of the digestive system include the following:
Digestion starts in the mouth. This is where the action of chewing begins to break down starchy foods into carbohydrates. Special glands inside the mouth release saliva. Saliva and the enzymes present in saliva also help accelerate the breakdown of starchy foods.
This organ pushes food from the mouth down to the next part of the digestive system, the stomach.
Once food drops down the esophagus, the muscles at the top of the stomach relax to allow the food to enter. After the food goes into the stomach, the muscles at the bottom of the stomach begin to move. The movement combines the food with the acidic digestive juices produced by glands in the stomach. The acid primarily breaks down foods containing protein. Eventually, the contents of the stomach are emptied into the small intestine.
The muscles of the small intestine mix food with its own digestive juices, along with those from the pancreas and liver. As the small intestine pushes the food toward the large intestine, these digestive juices help to further break down the food into carbohydrates, fats, and proteins. The walls of the small intestine then absorb nutrients from the digested food and deliver them into the bloodstream. From there, the blood carries the nutrients to cells throughout the body.
Not all food is broken down by the digestive system. Waste, or undigested food and dead cells, is pushed down to the large intestine. The large intestine absorbs the water and remaining nutrients from the waste before transforming it into solid stool. Stool is stored at the end of the large intestine, called the rectum, until it’s expelled from the body during a bowel movement.
While the hollow organs play critical roles in the digestive process, the solid organs release various chemicals that allow the digestive process to actually work.
The solid organs of the digestive system include the following:
The pancreas is located in the upper part of the abdomen, behind the stomach. It produces digestive juices that help the small intestine break down food into carbohydrates, proteins, and fats. It also makes chemicals that help regulate blood sugar levels, which affect how much energy the body has available to use.
The liver is a very large organ located above the stomach in the upper abdomen. Among its many important functions, the liver creates bile, a digestive substance that’s stored in the gallbladder. During digestion, bile is sent into the small intestine to help break down foods that contain fats. Besides aiding in the digestive process, the liver also stores nutrients and helps remove toxins from the body.
The gallbladder is a small pouch that stores the bile made in the liver. During digestion, the gallbladder releases bile into the top part of the small intestine to break down foods that contain fats.
Sometimes, one or more parts of the digestive system don’t work properly. This can cause anything from minor discomfort to serious health issues. Some common digestive system problems include:
Acid Reflux and GERD
Acid reflux occurs when stomach acid or bile flows back up into the esophagus, causing heartburn and other uncomfortable symptoms. Most people experience acid reflux from time to time, especially after eating spicy food or heavy meals. When acid reflux happens more than twice per week, however, the condition is considered gastroesophageal reflux disease (GERD). While acid reflux can cause some discomfort, GERD has the potential to cause serious health problems.
The symptoms of acid reflux and GERD include:
- a burning sensation in the chest (heartburn) that sometimes moves up to the throat
- a sour taste at the back of the mouth
- trouble swallowing
- dry cough
- sore throat
- regurgitating food or sour liquid
- feeling a lump in your throat
Gallstones are solidified chunks of digestive fluid that can form in the gallbladder. They can be as tiny as a grain of sand or as big as a golf ball. People may have one gallstone or several gallstones at the same time. Some people don’t need any treatment for their gallstones, while others may require surgery to remove their gallbladder.
There are two main types of gallstones: cholesterol gallstones and bilirubin gallstones. Cholesterol gallstones are yellow and made mostly of cholesterol. Bilirubin gallstones, on the other hand, are dark brown or black and contain bilirubin. Bilirubin is a chemical the body makes when it breaks down red blood cells.
A small gallstone may not cause any symptoms. A larger gallstone, however, often does cause symptoms. These symptoms may include:
- pain in the upper right section of the abdomen that radiates to the right shoulder or shoulder blades
- yellow tint in the skin or whites of the eyes (jaundice)
- clay-colored stools
Irritable Bowel Syndrome (IBS)
IBS is a collection of symptoms that affect the large intestine, causing extreme abdominal discomfort and pain. It’s a chronic condition that must be managed with long-term treatment. Most people with IBS can control their symptoms by modifying their diets and changing their lifestyle habits. Some people, however, may experience severe symptoms and need medication and counseling.
Common IBS symptoms include:
- abdominal pain or cramps
- mucous in the stool
Hemorrhoids, also called piles, are swollen veins around the anus or in the lower rectum at the end of the large intestine. Hemorrhoids can be internal or external. Internal hemorrhoids are located inside the rectum, while external hemorrhoids are located under the skin around the anus.
Some common symptoms of hemorrhoids include:
- bleeding during bowel movements
- itching or irritation around the anus
- pain or discomfort around the anus
- swelling around the anus
- a lump near the anus
- leakage of stool
While hemorrhoids can cause some discomfort, they can typically be treated with over-the-counter ointments, creams, or suppositories. More severe hemorrhoids that don’t resolve with simple home treatments may need to be treated with surgery.
Schedule an appointment with your doctor if you experience symptoms of any of the digestive disorders described above. You should also contact your doctor right away if you have severe pain or bleeding, or bleeding that is accompanied by lightheadedness or dizziness.
Keeping your digestive system healthy can help you avoid digestive problems. Follow these easy tips to keep your digestive system in tip-top shape:
- Eat seven or more servings of fruits and vegetables every day. Fruits and vegetables contain fiber, minerals, enzymes, vitamins and prebiotics that keep your digestive system healthy.
- Eat whole-grain breads, pastas, and cereals. Whole grains contain more fiber and nutrients than white “enriched” grain products and help your good colon bacteria flourish.
- Avoid processed meats, such as sausages and hot dogs, as they can cause problems with the digestive system. You should also limit your consumption of beef, pork, and lamb. These meats are most likely to carry bacteria that can harm the digestive system.
- Get enough calcium and vitamin D. You can prevent digestive problems by making sure you consume an adequate amount of calcium-rich foods and beverages, such as milk, tofu, and yogurt. Taking vitamin D supplements and safely increasing your exposure to sunlight can also help prevent digestive issues.
- Exercise regularly. Staying physically active can help maintain a healthy digestive system. Aim for 30 minutes of moderate to vigorous activity at least three days per week.
People who are overweight or underweight may be prone to more digestive problems. Exercising and eating a healthy diet can help lower your risk. If you’re struggling to lose or gain weight, talk to your doctor about what you can do.