ASGE Recognized Industry Associate (ARIA) Training Program for Regeneron | June 2022-GI_Tract_in_Health-Small_and_Large_Intestine

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The gastrointestinal tract is made up of various digestive organs, including the pancreas, esophagus, stomach, gallbladder, liver, small intestine, and large intestine. The small intestine is approximately 20-25 feet long and is responsible for digesting food and absorbing nutrients. It is divided into three sections: the duodenum, jejunum, and ileum. The duodenum is the first and shortest section of the small intestine, receiving bile from the liver and gallbladder and enzymes from the pancreas to aid in the breakdown of food. It is also where iron is absorbed. The jejunum is the mid-portion of the small intestine and is around 8-10 feet long. Its main function is the absorption of nutrients such as carbohydrates, fats, proteins, minerals, and some vitamins. The ileum is the final portion of the small intestine and continues the absorption of nutrients, as well as specialized absorption of bile salts and vitamin B12. <br /><br />The large intestine, also known as the colon, is the last part of the gastrointestinal tract and is approximately 4-5 feet long. Its main function is to absorb water and electrolytes and eliminate solid waste. Motility in the gastrointestinal tract relies on peristalsis, which is the coordinated contraction and relaxation of smooth muscles to mix and propel food downstream. The rectum retains stool until it is the appropriate time for elimination, and the anus has both involuntary and voluntary control over the release of stool. Defecation occurs when there is relaxation of the internal and external anal sphincters, along with the descent of the pelvic floor.<br /><br />Overall, the gastrointestinal tract performs vital functions in digestion, absorption of nutrients, and elimination of waste.

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Alexis P. Calloway, MD

Keywords

gastrointestinal tract

digestive organs

pancreas

esophagus

stomach

gallbladder

liver

small intestine

large intestine

peristalsis