One of the most important organs in our digestive system is the small intestine. The small intestine sits between the stomach and the large intestine and is by far the longest part of the digestive tract. In fact, it is estimated that it measures between 3 and 7 meters in length, influenced by very varied factors such as the height and size of the person himself.
Likewise, it is also important to bear in mind that the small intestine is an organ that fulfills a fundamental function within the digestive tract since it is in charge of absorbing most of the nutrients that we ingest. If you want to know a little more about the parts and functions of the small intestine, continue reading a HOWTO and we will tell you about it in detail.
Parts of the small intestine
The small intestine is located between the stomach and the large intestine and is divided into three well-defined parts:
- Duodenum – The duodenum is the first part of the small intestine. It is just after the stomach, which also makes it the part of the small intestine that is most closely related to this other organ. In fact, it is in the duodenum where both liver and pancreatic juices are secreted, essential in the digestion of food.
- Jejunum: The jejunum is the part of the small intestine that lies after the duodenum. This is characterized by already having the well-known shape of an irregular-looking tube that turns on itself. In the case of the jejunum, it is the irregular part of the small intestine that is in the upper half of the small intestine (with the exception of the duodenum). It is quite difficult to differentiate it from the ileum because there is no separation as tangible as in the case of the duodenum. Among the main differences, it should be noted that this part of the small intestine has a somewhat larger diameter than that of the ileum, as well as a greater number of intestinal villi.
- Ileum – The last part of the small intestine is the ileum, which corresponds to the lower half of the small intestine. The ileum is located below the jejunum and ends in the large intestine. It differs from the jejunum in that it has a somewhat smaller diameter and fewer intestinal villi.
Small intestine functions
The main function of the small intestine is the absorption of most of the nutrients that reach our body through ingestion. This occurs after the food has been digested in both the mouth and the stomach. In addition, thanks to the liver and pancreatic juices that are secreted in the duodenum, the food reaches the small intestine in almost completely liquid form, which facilitates the absorption of nutrients.
The absorption of nutrients is carried out by contact of these nutrients with the intestinal wall, which explains why it is such a long organ with so many folds. In fact, the inner surface of the small intestine is plagued with irregularities in the form of intestinal villi which, in addition to allowing the absorption of nutrients, also allow the surface through which said absorption is carried out to be enlarged, making this organ one of the most efficient in the human body.
Small intestine diseases
The small intestine, like any other organ in the body, can become ill and present discomfort and pain to patients suffering from any problem related to it. Some of the most common diseases related to this organ are the following:
- Vascular diseases: these are diseases that usually occur in the small intestine due to the high number of arteries and veins that surround this organ (necessary for nutrients to pass into the blood). These types of diseases usually manifest as hemorrhages that affect the intestinal area and that, depending on the case, can be more or less serious.
- Celiac disease: this is a disease characterized by intolerance to gluten, a protein present in some cereals such as wheat, oats, or barley. It is an autoimmune disease that, among different symptoms, causes the atrophy of the intestinal villi, which leads to a worse absorption of the ingested nutrients.
- Crohn’s disease – This disease of the intestine manifests itself as irritation and inflammation of the intestinal walls. It usually manifests mainly in the area of the small intestine corresponding to the ileum, as well as in part of its continuation in the large intestine.
- Tumors: Tumors can manifest in many organs of the body, including the small intestine. The presence of tumors does not necessarily imply that they are malignant tumors. However, it will be the doctors who will determine the nature of the tumors and the most appropriate treatment in each case.
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