What Are The 6 Main Functions of The Digestive System?

The human body is an amazing thing, from the crown of your head to the tips of your toes. One of the most interesting systems, though, would have to be the digestive system. Made up of the mouth, stomach, intestines and other organs, the digestive system plays a tremendous role in our health and wellness. Aside from taking the food people eat and turning it into wholesome energy, there are six digestive system functions.

These six primary functions include the following:

  1. Food ingestion
  2. Secretion of digestive enzymes and other fluids
  3. Moving food and waste through the body (mastication, peristalsis, and segmentation)
  4. Food digestion
  5. Nutrient absorption
  6. Waste excretion

We’re going to discuss these six digestive functions today so you can better understand what’s happening every time you take a bite.


The first function of the digestive system is ingestion, or the taking in of food. The mouth is where ingestion happens, since that is how we consume of meals and beverages.


Throughout the day, the digestive system can secrete around 7 liters of fluid. This includes saliva, mucus, enzymes, hydrochloric acid, and bile. Saliva is found in the mouth and contains enzymes that start the digestion of carbohydrates. Other enzymes found later on in the digestion tract help break down proteins and facts. Mucus lines the esophagus and other sections of the GI tract to lubricate the organs and help move the food along. In the stomach, we find hydrochloric acid, which helps kill bacteria on our food. Lastly, there is bile, which emulsifies fats (lipids) for easier digestion.

Mastication, Peristalsis & Segmentation

Otherwise known as the mixing and movement of food, the three combined functions of mastication (chewing), peristalsis, and segmentation take place sequentially. Chewing and swallowing break food down and help move it through to the esophagus and stomach. Then, peristalsis, which are waves of muscular contractions, helps move food from the esophagus to the stomach and intestines. Segmentation occurs last, in the small intestine, and works to squeeze out any remaining nutrients from the food.


Next, we have digestion. As mentioned above, there’s a number of fluids and enzymes that help back down the food and maximize digestion of nutrients, starting from the moment carbohydrates hit your tongue and all the way through to the pancreas and duodenum.


Once the food has been reduced down to a molecular level, absorption starts to occur. Things like water and alcohol are absorbed quickly into the bloodstream, but most absorption happens within the small intestine. Meanwhile, the large intestine absorbs water and the vitamins B and K before the final function.


Excretion is also known as defecation. This is the final digestive system function. Defection happens to remove waste, such as indigestible substances and toxins from the body so that it doesn’t pile up inside the GI tract.

In conclusion, the six digestive functions of the human body take place in multiple regions throughout the body, starting with ingestion in the mouth to excretion from the large intestine. The six functions in digestion play a significant role in our wellbeing, so knowing how ingestion, secretion, mixing and moving, digestion, absorption, and excretion work is essential to ensuring balance within the body.

Leave a Reply