The largest digestive organ breaks down food and absorbs nutrients
The small intestine is part of thedigestive system.
This article explains the anatomy and function of the small intestine.
It also discusses associated conditions and treatments.
Libre de Droit / Getty Images
Libre de Droit / Getty Images
What Is the Small Intestine?
It is contained in the central and lower abdominal cavity.
What Does the Small Intestine Do?
The jejunum lies between the duodenum and the ileum.
Each segment of the small intestine has a different function.
In addition, iron is absorbed in the duodenum.
The jejunum comprises approximately 40% of the small bowel in humans.
Over 95% of the bodys carbohydrate and protein absorption takes place in the jejunum.
Ileum
The ileum is the distal end of the small intestine that opens into the large intestine.
The ileum comprises approximately 60% of the small bowel in humans.
The ileum receives the food from the jejunum and empties into the large intestine.
This includes vitamin B12, bile salts, and more.
Many conditions of the small intestine can impact the villi, resulting in malabsorption of nutrients.
Biliary System
The pancreatic and bile ducts form an important system called thebiliary system.
This attaches to the liver, pancreas, and the duodenum.
Mesentery
The mesentery is a contiguous structureone that touches and shares a common border.
It attaches the small intestine and the large intestine to the back of the abdominal wall.
It is a thin, vascular layer, composed of a double fold of peritoneum.
One purpose of the mesentery is to supply blood to the intestines.
In the small intestine:
The small intestine serves as a major transportation system for lymph fluid.
Enteric Nervous System
The term enteric means related to the intestines.
One small intestine function is to coordinate many of its activities, including its movements.
It does this because the small intestine has a highly integrated nervous system, called theenteric nervous system.
This is what keeps the intestinal contents moving along the intestinal tract for proper digestion and absorption of nutrients.
The treatment for congenital conditions along the small intestine often involves a surgical procedure to correct the problem.
The pop in of operation depends on the issue and where it is located.
These include:
Summary
The small intestine extends from the stomach to the colon.
It is made up of three sections called the duodenum, the jejunum, and the ileum.
The functions of the small intestine include the digestion of food and absorption of nutrients.
Certain conditions are associated with the small intestine and many can impact how well nutrients are absorbed.
Treatment for small intestine-related issues can vary and may include medications, diet changes, and surgery.
Colorado State University.Gross and microscopic anatomy of the small intestine.
2016;143(13):2261. doi:10.1242/dev.135400
University of California San Francisco Vascular & Endovascular Surgery.Mesenteric ischemia.
Collins JT, Badireddy M.Anatomy, abdomen and pelvis, small intestine.
National Institute of Diabetes and Digestive and Kidney Diseases.Symptoms and causes of GI bleeding.
