The Formation of Feces PDF

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How Feces Form...

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The Formation of Feces •

By the time the chyme has remained in the large intestine for 3 to 10 hours, it is a semisolid mass of material as a result of the absorption of water and is now known as feces.

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The feces consist of water, inorganic salts, and epithelial cells from the mucosa of the tract that were scraped away as the chyme moved through the tract.

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In addition, the feces have bacteria, in particular Escherichia coli, a normal inhabitant of our intestine that feeds on undigested materials.

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The products of bacterial decomposition such as gas and odor (hydrogen sulfide gas, H2S, which produces a "rotten egg" odor), and undigested parts of food not attacked by bacteria are also found in feces.

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The more fiber (the cellulose of plant walls from eating fruits and vegetables) in the diet, the more undigestible materials in the feces and the softer the stool.

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When mass peristalsis pushes the fecal material into the rectum, it causes distention of the rectal walls.

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This triggers pressure-sensitive receptors in the walls of the rectum, sending an impulse to the nervous system, which initiates the reflex for defecation.

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Defecation is the act of emptying the rectum and is the final activity of the digestive system....