The human digestive system is a complex and efficient system that converts food into the nutrients needed for the body to function. The digestive process begins in the mouth with chewing and saliva. Food then travels down the esophagus to the stomach where it is mixed with stomach acid. From there, food moves into the small intestine where enzymes break down nutrients so they can be absorbed into the bloodstream. The large intestine absorbs water and electrolytes from feces before eliminating them through defecation.
The digestive system is composed of several organs that work together to break down food and absorb nutrients. These organs include the mouth, esophagus, stomach, small intestine, large intestine, and rectum/anus.
The mouth is responsible for breaking down food through chewing and saliva. Chewing breaks down food mechanically while saliva contains enzymes that begin to chemically break down carbohydrates (such as starches).
The esophagus is a long tube that connects the throat (pharynx) to the stomach. It propels swallowed food downward using rhythmic contractions called peristalsis. A ring of muscle at the bottom of the esophagus (the lower esophageal sphincter) prevents swallowed air from entering the stomach. If this muscle relaxes abnormally or weakens over time, gastroesophageal reflux disease (GERD) can occur, in which case stomach contents including acid may be regurgitated back up into the throat causing heartburn or other symptoms.
The stomach is a sac-like organ located between the esophagus and small intestine. It stores swallowed food and mixes it with gastric juice containing acids and enzymes that further break down carbohydrates, proteins ,and fats . This combination of partially digested food and gastric juice is called chyme . When chyme enters