Facts About the Small Intestine

Every human has a system of incredibly long, hollow and narrow tubes inside their bodies, which integrate a major part of the digestive system. This part of the digestive system is divided into large and small intestines, and this article is going to mention some important facts about the latter. This organ is incredibly long, in fact, a regular human usually has 20-feet long small intestines. They are commonly one inch in diameter. Their smooth, velvety tissue is divided into three parts: the duodenum, the jejunum and the ileum.

The main function of the small intestine regards the absorption of nutrients, and this process happens with the help of villi, which is a finger-like tissue covering the intestines. This structure is also covered by even smaller tissue called microvilli, and both create a surface area big enough for minerals and other helpful substances to be absorbed. 

The way the small intestine operates is like this: food comes through the shortest, uppermost part of the small intestine, the duodenum. This part makes only about one-fifth of the length of the whole organ. While the partially digested food is being held in there, the liver, the gallbladder, and the pancreas start sending their enzymes to help break it down. Then, the food moves on to the jejunum and the ileum. In this stage, the villi and the microvilli absorb all the nutrients they can, which is about 95% of it. The remaining material moves to the large intestine.

What movement helps the food go forward?

It is crucial for your chyme, the semi-processed food coming from your esophagus, to run through the organs so it can deliver its nutrients in a better way. This movement is known as peristalsis, which can be described as a wave-like muscular action pattern. Your small intestine is capable of moving and holding around 4 pounds of food at a time.

Your intestines carefully discriminate what you eat

It is still unclear for many scientists how the small intestine does this, but it discriminates between “healthy” substances like food, water and vitamins, and “unhealthy” substances such as parasites, dangerous bacteria, and viruses. 

What are the most common small intestine diseases?

Celiac disease has become a very common condition, in which the small intestine does not properly absorb the nutrients from food, and this is caused by an “allergy” to gluten (a protein inside the bread and other types of carbohydrates). It can lead to severe abdominal pain and weight loss. Diarrhea can also be considered very usual, and it can be caused by mild and limited infections either in the colon or in the small intestine.  

There is more than just half-processed food inside our small intestine

A wide range of microorganisms as bacteria, viruses, protozoa, and even worm parasites live inside your small intestines, and it is known as the microbiome. This seemingly dangerous beings, in fact, help us stay healthy. However, the composition of it can change due to many factors like our food habits, stress, and antibiotics.