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What Is the Histology of the Duodenum?

Andrew Kirmayer
Andrew Kirmayer

In humans, the small intestine is usually consists of three sections; the first, as food passes from the stomach, is the duodenum. The jejunum and ileum are other parts, typically differentiated by the types of cells that line the inside of the tract. This first section is a tube-like structure that is generally 9.8 to 11.8 inches (25 to 30 centimeters) long. It is usually composed of several layers. The histology of the duodenum is also characterized by microscopic structures called Brunner’s glands, which can secrete mucus that neutralizes stomach acids.

Food often enters the organ after up to four hours after eating. Small ducts can allow pancreatic enzymes and bile to flow in, which also neutralize acids as well as help with digestion. The histology of the duodenum typically represents a folded structure, especially in the mucosa layer, which is typically made up circular or transverse folds. There are also projections called villi, which are up to 0.04 inches (1 millimeter) long. At their core are lymph and blood vessels as well as nerves.

Villi, or tiny projections, line the wall of the small intestine.
Villi, or tiny projections, line the wall of the small intestine.

Usually inside the villi is a microscopic layer called a brush border, which is made up of hair-like parts of cells called microvilli. There are also goblet cells, which secrete mucous to help food pass through the tube. Microfold cells also make up the histology of the duodenum; they normally function by presenting antigens and line a series of lymphatic nodules. Cells called lymphocytes are often found in a deeper layer called the lamina propria, which also consists of connective tissues. The lymphatic structures can be concentrated in certain areas, while glands typical of the intestines are found in this layer as well.

The duodenum is the first section of the small intestine.
The duodenum is the first section of the small intestine.

Intestinal glands, called Crypts of Liberkuhn, are generally tube-shaped and open at the inner surface of the duodenum. There are usually mucous and other endocrine-secreting cells as well. The submucosa layer is typically the location of the Brunner glands, which are only found in the histology of the duodenum. Generally identified by a coiled, branched tubular shape, these are lined by mucous secreting cells and typically connect with ducts that lead to the intestinal glands.

The histology of the duodenum is characterized by microscopic structures called Brunner's glands.
The histology of the duodenum is characterized by microscopic structures called Brunner's glands.

A circular layer and longitudinal layer of muscle usually makes up a significant part of the histology of the duodenum called the muscularis. The outer layer is typical of that found throughout the small intestine, while the serosa generally forms the outer part of the duodenum. This layer is also a component of the peritoneum, or the tissue that surrounds the abdominal organs.

Discussion Comments

Porcupie

Hey, I'm also a colon cancer survivor. I take it you have an ostomy of some kind? The duodenum absorbs carbohydrates and proteins. If you don't have it, you will have trouble absorbing these nutrients . In the article it talks about intestinal villi. With short bowel syndrome, you have less surface space for the villi to do their job, and this usually results in nutritional and dehydration issues. What are your symptoms? I'm not an expert or anything, so if someone has better advice...please chime in.

BronzeEagle

I went through colon cancer recently. It's called HNPCC, and is genetic. Radiation severely burned my intestines and I've had 12 surgeries because of radiation enteritis. As a result, I've lost almost half of my small intestine and almost all of my colon. I know a lot of people from the Cancer Survivors Network who suffer from short bowel syndrome after colon cancer. I think it has a lot to do with the duodenum as well as the amount of small intestine removed. Does anyone know what happens when the duodenum is removed?

Thanks to anyone who posts. I'm just trying to understand my "new" body better.

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    • Villi, or tiny projections, line the wall of the small intestine.
      By: Sebastian Kaulitzki
      Villi, or tiny projections, line the wall of the small intestine.
    • The duodenum is the first section of the small intestine.
      By: nerthuz
      The duodenum is the first section of the small intestine.
    • The histology of the duodenum is characterized by microscopic structures called Brunner's glands.
      By: WavebreakmediaMicro
      The histology of the duodenum is characterized by microscopic structures called Brunner's glands.
    • The serosa generally performs the outer part of the duodenum.
      By: stockshoppe
      The serosa generally performs the outer part of the duodenum.
    • The pancreatic duct, which introduces bile and pancreatic juice into the small intestine, is directly connected to the descending duodenum.
      By: kaianni
      The pancreatic duct, which introduces bile and pancreatic juice into the small intestine, is directly connected to the descending duodenum.
    • An endoscopy may be used to diagnose and treat conditions associated with the duodenum.
      By: Max Tactic
      An endoscopy may be used to diagnose and treat conditions associated with the duodenum.
    • Intestinal glands are generally tube-shaped and open at the inner surface of the duodenum.
      By: graphicgeoff
      Intestinal glands are generally tube-shaped and open at the inner surface of the duodenum.