Digestive Systemdescribe, 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

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Date Submitted: 09/17/2010 12:56 PM

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The sight and smell of food spurs the beginning of the digestive process through the salivary glands. Food is dampened by salvia and chewed by the teeth once it enters the mouth, transforming into a bolus. The bolus then leaves the mouth and travels toward the pharynx, where it is then swallowed. It continues then toward into the esophagus, which acts as a tunnel connecting the pharynx to the stomach. After the bolus enters the stomach, it is merged with acid secretions to convert the bolus into a semi-liquid food mass called chyme. The stomach partially digests the food and chyme typically vacates the stomach in two to six hours, depending on the quantity and type of meal that is indigested.

The food is then transferred to the small intestine, where the majority of digestion and absorption of nutrients from food occurs. The small intestine is separated into three parts: the duodenum, the jejunum, and the ileum. Bile secretions from the liver and gallbladder aid in digesting and absorbing fat from food while the bicarbonate secretions from the pancreas and digestive enzymes help with the digestive process.

Any material that is not absorbed by the small intestine then enters into the large intestine through a sphincter, which acts as a barrier to keep food from re-entering the small intestine. The colon and the rectum both occupy the large intestine. Further absorption of water and certain vitamins and minerals


takes place in the colon, while the materials that are not absorbed expel from the body as waste through the anus, the outer opening of the digestive tract.

Digestive systems

Digestive systems take many forms. There is a fundamental distinction between internal and external

digestion. External digestion was the first to evolve, and mostf un g i still rely on it.[2]In this

process,e nzyme s arese cre t ed into the environment surrounding the organism, where they break down

an organic material, and some of the productsd if f u se back to the...