CheckPoint: Human Digestion
Describe, in 200 to 300 words, the path food follows through the digestive system and how digestion occurs in each of the following parts of the digestive system. •
Include descriptions of other organs or components of the digestive system, including:
After food enters the mouth and after being chewed by the teeth, the food then transforms into a bolus. Bolus refers to the soft mass of chewed food that passes through the digestive system. The bolus then leaves the mouth and moves into the pharynx. The bolus then travels down into the esophagus, which leads to the stomach. Once the bolus enters the stomach, it begins to mix with the acid secretions transforming the bolus into chyme. Chyme is the semifluid mass of partially digested food expelled from the stomach in to the duodenum. Depending on the size and type of meal digested, chyme usually empties from the stomach in 2 to 6 hours. The liver, gallbladder and pancreas begin to contribute to the digestive process once the chyme reaches the small intestine.
A great deal of the digestion and absorption of nutrients from food takes place once the chyme or food reaches the small intestine. Secretion of bile from both the live and the gallbladder aids with the digestion and absorption of fat. At the same time, digestive enzymes and bicarbonate secretions from the pancreas assist in the digestive process. The excess materials not absorbed in the small intestine then travel into the large intestine via the sphincter. Both the colon and the rectum are associated with the large intestine; adding the absorption of water, vitamins and minerals, once the material enters the rectum. The material that was not absorbed in the colon travel into the anus, then is excreted from the body in the form of waste products, known as feces. This digestive process can take anywhere from 3-5 hours up to 24 hours.
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