Digestion Essay

744 Words 3 Pages
Digestion is the process of breaking down food by mechanical and enzymatic action in the alimentary canal into substances that can be used by the body. The process of digestion is the way that the body obtains nutrients, fats, carbohydrates, minerals and vitamins necessary to maintain life. Carbohydrates are comprised of complex sugars, which the body will convert to simple sugars for use in numerous ways. Fats are comprised of fatty acids and glycerol. Proteins are made up of many types of amino acids, which the body can break down and reconstruct to use as needed.
The process of digestion begins with the mechanical action of chewing. The mouth has four different types of teeth that each serves a purpose. The incisors, canines, premolars and
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In the esophagus is the first place peristalsis occurs. Peristalsis is the rhythmic contractions of smooth muscle in the esophagus and the intestines that aids in the progression of food through the tract. Peristalsis is controlled by the parasympathetic nervous system. When digestion begins, signals are sent to and from the brain that controls movement and the release of enzymes or hormones. There are two types of nerves that control digestion: extrinsic and intrinsic. Extrinsic nerves control movement, such as peristalsis. Intrinsic nerves control the release of enzymes and hormones. At the end of the esophagus is a “gate” called the esophageal sphincter (also known as the cardiac sphincter). This allows the one directional travel of food or liquids and prevents …show more content…
This opening allows chyme to enter into the small intestine. The small intestine is composed of 3 parts: duodenum, jejunum and ileum. The duodenum is the only part of the small intestine that continues to break down food with the release of bile. While the stomach releases hydrochloric acid and creates an acidic environment with a low pH, the duodenum is slightly basic with a higher pH. Bile, which is produced in the liver and stored in large quantities in the gall bladder, is released to emulsify and breakdown fats at this point. For the remainder of the time in the small intestine, food passes by peristalsis and comes into contact with millions of villi. Villi are small projections that are used for nutrient absorption. The small intestine is able to absorb a large amount of nutrients because villi increase the surface area, making it approximately the similar surface area of a large football

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