Your Digestive System

Your digestive system is made up of a series of organs that allows your body to get the nutrients and energy it needs from the food we eat.  As food travels through the digestive system it is broken down, sorted, and reprocessed before being circulated around the body to nourish and replace cells and supply energy to our muscles. 

Digestion starts in the mouth where chewing and saliva breaks down food so it is more easily processed by your body. 

Esophagus: The esophagus is a muscular tube that connects the pharynx (throat) to the stomach. The esophagus contracts as it moves food into the stomach. A “valve” called the lower esophageal sphincter (LES) is located just before the opening to the stomach. This valve opens to let food pass into the stomach from the esophagus and it prevents food from moving back up into the esophagus from the stomach. 

Medical conditions related to the esophagus:

Stomach:  An organ with strong muscular walls, the stomach holds the food and mixes it with acid and enzymes that continue to break the food down into a liquid or paste.  

Small Intestine (Small Bowel): Almost 20 feet long, the small intestine is the workhorse of the digestive system. It will continue to break down food with enzymes released by the pancreas and bile released from the liver. It is made up of three segments, the duodenum, which continues the breakdown of food; and the jejunum and ileum, which are mainly responsible for the absorption of nutrients. 

Medical conditions related to the small bowel:

Pancreas: Your pancreas is located behind your stomach and is attached to both your gall bladder and your small intestines. Among other functions, the pancreas aids in digestion by producing digestive enzymes and secreting them into the duodenum (the first segment of the small intestine).  These enzymes break down protein, fats, and carbohydrates.

Medical conditions related to the pancreas:

Liver: An organ with many functions, your liver’s two main responsibilities in the process of digestion are to make and secrete bile and to process and purify the blood containing newly absorbed nutrients that are coming from the small intestine. Bile has two main purposes: to help absorb fats and to carry waste from the liver that cannot go through the kidneys. 

Medical conditions related to the liver:

Bile Ducts:  Bile made in the liver travels to the small intestine through the bile ducts.  If the bile isn’t needed immediately, it is stored in the gallbladder.

Medical conditions related to the bile ducts:

Gallbladder:  A pear-shaped reservoir located just under the liver that receives and stores bile made in the liver.  The gallbladder sends this stored bile into the small intestine to aid in the digestion of food.

Colon (Large Intestine):  A 5- to 7-foot-long muscular tube that connects the small intestine to the rectum and is responsible for processing waste so that defecation is easy and convenient.  It is made up of the ascending (right) colon, the transverse (across) colon, the descending (left) colon and the sigmoid colon, which connects to the rectum. 

Medical procedure related to the colon:

Rectum:  An 8-inch chamber that connects the colon to the anus.  The rectum receives stool from the colon, sends signals to the brain if there is stool to be evacuated, and holds stool until evacuation can happen.

Anus:  The last part of the digestive tract, the anus, consists of pelvic floor muscles and two anal sphincters (internal and external).  Together their jobs are to detect rectal contents, whether they are liquid, gas or solid, and then control when stool should and shouldn’t be excreted from your body. 

University of Michigan program related to the anus:


Medical Conditions Involving Multiple Digestive Organs

There are many medical conditions that involve more than one digestive organ. These include: