The jejunum is the middle small intestine section. Above all, it ensures the nutrient uptake into the blood. Read more about the jejunum!


The jejunum (Jejunum) is the middle section of the small intestine between duodenum (duodenum) and ileum (ileum). It accounts for about two-thirds of the length of the entire small intestine. In the jejunum, nutrients and water are absorbed from the porridge. The rest is transported further to the ileum. Read all about the Jejunum!

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  • What is the jejunum?

  • What is the function of the jejunum?

  • What problems can the jejunum cause?

What is the jejunum?

The jejunum, the jejunum, is the middle part of the small intestine, lying between the duodenum and the ileum. There is no clear distinction to the latter. Both together (jejunum and ileum) are also called small intestine convolutes.

The jejunum begins at the level of the second lumbar vertebrae and is about two to two and a half feet long. Like the ileum, it is suspended on the posterior abdominal wall by a peritoneal duplication, the so-called mesentery, which forms numerous freely movable loops.

The wall of the jejunum consists of a double layer of musculature, which is covered on the inside by mucous membrane and outside by the peritoneum. The mucous membrane has many Kerckring wrinkles and Lieberkühn glands on. The Kerckring wrinkles are transverse mucosal folds which greatly increase the inner surface of the jejunum. This increases its absorption capacity.

The Lieberkühn glands are tubular depressions in the wall of the small intestine. They serve as the Kerckring wrinkles on the one hand, the surface enlargement. On the other hand, they secrete enzymes that are important for digestion.

Small intestinal villi (finger-shaped protuberances of the intestinal wall) as well as the tiny, filamentous processes on the cell surface of the epithelium (microvilli) additionally increase the inner surface of the jejunum.

Where does the name Leerdarm come from?

The German term jejunum comes from the fact that this part of the small intestine is usually empty in the deceased.

What is the function of the jejunum?

In the jejunum, the enzymatic splitting of the food components, which has already begun in upper sections of the digestive tract, continues. The resulting components of the main nutrients (simple sugars, amino acids, fatty acids, etc.) as well as water, vitamins and electrolytes are absorbed into the blood (absorption).

In addition to the resorption function of the jejunum also has a glandular function: The goblet cells in the intestinal mucosa produce a mucus that covers the entire inner surface, thus protecting the mucosa from self-digestion by the acid from the stomach.

Another important function fulfills the muscular wall of the jejunum:

  • Segmentation movements divide the porridge by pinching into smaller portions
  • Pendulum movements mix the intestinal contents by moving it back and forth so that it comes into constant contact with the digestive juices
  • Peristaltic movements of the jejunum wall transport the intestinal contents further towards the ileum

There are many organs in the abdomen. And all can cause pain. See here, when you have to take the complaints seriously.

What problems can the jejunum cause?

Isolated diseases of the jejunum are rare. In most cases, the entire small intestine is affected, such as in small intestinal inflammation (enteritis) or acute closure of the small intestine supplying artery (mesenteric artery infarction).

Chronic inflammatory bowel disease (CED) Crohn's disease can affect the small intestine in addition to the colon. In contrast, the ulcerative colitis - also a CED - limited to the colon.

In the genetic intolerance to gluten (gluten protein in the grain), the mucous membrane in the small intestine (also in the jejunum) is damaged by a malfunction of the immune system, which impairs nutrient absorption.

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