Jejunum

Your jejunum (pronounced “jeh-JYOO-num”) is the middle section of your small intestine. It’s located between the other parts of your small intestine — the duodenum and the ileum. The main function of your jejunum is to help with digestion. It also absorbs nutrients from foods into your bloodstream. These include carbohydrates, proteins, fats, vitamins and minerals.

Maintaining a healthy jejunum is important for overall digestion and nutrient absorption. Consuming healthy foods, staying hydrated and getting regular physical activity can help keep this part of your small intestine working properly.

Jejunum function

Your jejunum has several key functions. These include:

• Digestion: It’s a key step in the digestive process. It breaks down food that comes from your duodenum.
• Absorption: It’s the main site where nutrients from food are absorbed into your bloodstream. It also absorbs large amounts of water.
• Peristalsis: It continues the involuntary action of rapid muscle contraction. This keeps food moving toward your ileum.

Jejunum location

Your jejunum is located in the upper left part of your abdominal cavity. It sits between the first part (duodenum) and the last part (ileum) of your small intestine.

Your jejunum is attached to the back of your belly (abdomen) by a fold of tissue called the mesentery. This tissue holds your jejunum in place and carries blood vessels, nerves and lymph.

What are the parts of the jejunum?

From the inside to the outside, your jejunum has four main layers:

• Mucosa: This innermost layer has tiny finger-like projections called villi. These increase the surface area, which helps better absorb nutrients and water.
• Submucosa: This is a layer of loose connective tissue with blood vessels, lymph nodes and nerves.
• Muscularis externa: This includes two layers of muscle. These are the inner circular and the outer longitudinal muscle layers. They help move food along.
• Serosa: This outermost layer is made of a thin layer of tissue that covers and protects your jejunum.

What does it look like?

Your jejunum is shaped like a tube. Its internal diameter (width) is about 1 inch (2.5 centimeters). That’s why it’s called your “small” intestine.

Your jejunum is flexible and coiled in loops. It has large circular folds that make it look delicate and feathery on imaging or under a microscope.

What color is it?

Your jejunum is a deep red color. That’s because of its rich blood supply and thick wall. Your ileum, on the other hand, is generally pink and has a thinner wall.

How long is the jejunum?

Your jejunum is about 8 feet (2.5 meters) long. It makes up about two-fifths of the total length of your small intestine.

What are the common conditions and disorders that can affect the jejunum?

Several health conditions can affect your jejunum. These include:

• Crohn’s disease: This is an inflammatory bowel disease. It causes the lining of your jejunum to get inflamed, so it can’t absorb food properly.
• Celiac disease: This is an autoimmune disorder triggered by gluten. Gluten damages the lining of your jejunum. That makes it hard for it to take in nutrients.
• Jejunal diverticulosis: This disease causes small pouches to form in the wall of your jejunum. The pouches can trap food, which can lead to pain or infection.
• Jejunal atresia: This is a condition that’s present from birth (congenital). It happens when part of your jejunum is missing or blocked, so food can’t pass through.
• Small intestinal bacterial overgrowth (SIBO): This is a condition that causes too many bacteria to grow in your jejunum. That can interfere with nutrient absorption.

Signs/symptoms something isn’t working right

If your jejunum can’t absorb nutrients properly, your body may feel weak, ill or uncomfortable. Symptoms you may notice include:

• Stomach pain or cramps
• Bloating or gas
• Diarrhea
• Unexplained weight loss
• Nausea or vomiting
• Fatigue

How can I keep my jejunum healthy?

To help keep your jejunum healthy:

• Eat plenty of fiber-rich foods (fruits, vegetables, whole grains)
• Include lean proteins (chicken, fish, beans) and healthy fats (olive oil, nuts, avocado)
• Avoid processed and fried foods as well as excess sugar and artificial sweeteners
• Eat smaller, more frequent meals instead of very large meals
• Stay hydrated with plenty of water
• Limit alcohol
• Get regular physical activity
• Manage stress