Digestive System: Function, Diseases


The digestive system is an important part of your body, responsible for turning food into energy, growth and cell repair. This system comprises mouth, esophagus, stomach, small intestine, pancreas, liver, gallbladder, large intestine (colon), rectum and anus.


  • Mouth

Your mouth is the first part of the digestive tract. As soon as you have the first bite of food, the digestion process begins here. After chewing, the food will be broken into pieces that can be more easily digested. At the same time, saliva performs the function of beginning the process of breaking food into certain forms so that your body can absorb and use it.

  • Esophagus

The esophagus refers to a muscular tube extending from the throat, also called pharynx, to the stomach. Once you swallow, your brain signals the muscle of the esophagus to start a series of contractions, called peristalsis, by which food is delivered to your stomach. A “valve” called the lower esophageal sphincter helps prevent food from passing backward into the esophagus.

  • Stomach

The stomach is a hollow organ with strong muscular walls. In addition to holding food, the stomach continues the breakdown process by mixing food with strong acid and powerful enzymes secreted by cells in the lining of the stomach. When the process is done, food that becomes the consistency of a liquid or paste, will be released into the small intestine.

  • Small intestine

The small intestine is a 22-foot long muscular tube loosely coiled in the abdomen, consisting of three segments: the duodenum, jejunum and ileum. This organ continues to break down food with enzymes released by the pancreas and bile from the liver. What’s more, peristalsis promotes the process by moving food through and mixing it with secretions from the pancreas and liver. The duodenum mainly focuses on the breakdown, while the other two parts help absorb nutrients into the bloodstream.

  • Pancreas

The pancreas secretes digestive enzymes into the duodenum. Protein, fats, and carbohydrates can be broken down by the enzyme. Besides, the pancreas also secretes insulin directly into the bloodstream, which is the chief hormone for metabolizing sugar.

  • Liver

The liver has many functions, among which the most important one is to process the nutrients absorbed from the small intestine. Bile from the liver is also important for the digestion of fat. In addition, it performs other functions such as making various chemicals the body needs to function and detoxifying potentially harmful chemicals.

  • Gallbladder

The gallbladder works to store and concentrate bile and release it into the duodenum.

  • Large intestine (colon)

The large intestine is a 5- to 6-foot-long muscular tube that connects the small intestine to the rectum. It includes the cecum, the ascending (right) colon, the transverse (across) colon, the descending (left) colon, and the sigmoid colon. In this organ, waste will be processed so that emptying the bowels can be easy and convenient. Peristalsis occurs again, passing stool or waste, which is first in a liquid state and finally in a solid form, through the colon. And stool will be stored in the sigmoid colon until a “mass movement” empties it into the rectum. Once the descending colon is filled with stool, the contents will be delivered into the rectum to get ready for the elimination.

  • Rectum

The rectum is an 8-inch chamber that connects the colon to the anus. After receiving stool from the colon, it makes you feel that you need to evacuate stool. But your brain decides whether the evacuation can happen. If the stool cannot be released, your rectum holds it until the brain gives an instruction.

  • Anus

The last part of the digestive system is the anus, a 2-inch long canal made up of the pelvic floor muscles and the two anal sphincters (internal and external). The lining of the upper anus enables us to know whether the contents are liquid, gas or solid. Sphincter muscles surrounding the anus play an important role in allowing control of stool. By creating an angle between the rectum and the anus, the pelvic floor muscle stops evacuating when you do not want to. The internal sphincter, which is always tight, except when stool enters the rectum, keeps us continent in the condition when you are unaware of the presence of stool. External sphincter performs its function when you have an urge to release the contents. It helps you hold the stool until you reach a toilet.

Digestive diseases

There is no doubt that the health of your digestive system has a great impact on your life. Sometimes the organs of the system may develop medical conditions. These conditions may affect a part of one organ, or a particular organ, or even more than one organ. Here are some common digestive diseases:

  • Ulcers

Ulcers are open sores or lesions that can develop on the walls of the esophagus, stomach, and duodenum. Various factors may result in ulcers, such as stress, lifestyle and medication.

  • Gastroesophageal Reflux Disease (GERD)

GERD is a common digestive condition caused by the abnormal reflux of the stomach contents to the esophagus. The main symptom is heartburn.

Bacterial infection, regular use of medication like NSAIDs, and excess alcohol consumption may cause gastritis whose symptoms include bloating, vomiting, diarrhea, indigestion and abdominal pain.

  • Celiac disease

Celiac disease is a type of autoimmune disease. The immune system of people with this condition reacts to gluten in some food products, affecting nutrient absorption.

Crohn’s disease is a condition in which the walls of the digestive tract become inflamed. In addition to the intestine, which is mainly affected, other parts of the digestive tract may also develop this condition. People with Crohn’s disease may have ulcers, diarrhea, abdominal pain and blood in stools.

Ulcerative colitis is also an inflammatory condition. It affects the large intestine, leading to ulcers, abdominal pain and even perforation of the colon as well as other complications.

  • Anal fissures

Anal fissures, characterized by rectal bleeding and pain, are cracks or cuts on the skin lining the anus. It often results from hard stools. Anal sex, syphilis, and HIV may also result in the condition.

There are many other conditions associated with the digestive system. You can consult your doctor to get more information about the diseases.

Keyword: digestive system.

Related Posts:

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What are the Symptoms of Esophageal Ulcers?

Do You Know How to Heal Gastritis Quickly?

Crohn’s Disease: Symptoms, Treatment

What to Know About Foods and Ulcerative Colitis?

* The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.