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Esophagus & Stomach

Esophagus & Stomach. By Claire Allen, Christie Batt and Em Layton. ESOPHAGUS. Aka foodpipe Around 25cm long Composed of a series of layers- including circular and longitudinal muscles Peristalsis enables bolus to be propelled towards the stomach.

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Esophagus & Stomach

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  1. Esophagus& Stomach By Claire Allen, Christie Batt and Em Layton

  2. ESOPHAGUS • Aka foodpipe • Around 25cm long • Composed of a series of layers- including circular and longitudinal muscles • Peristalsis enables bolus to be propelled towards the stomach. Circular muscles contract behind the bolus and relax in front of it- so that it is pushed along. These are often referred to as wave-like contractions due to the circular shape of the muscle fibres and the way they contract. The longitudinal muscles contract to shorten the section of the esophagus with the bolus present- this speeds up the time taken to the stomach. Food moves along the esophagus at a rate of around 4cm per second and takes around 6 seconds to travel from the mouth to the stomach in total.

  3. STOMACH • Elastic muscular sac that stretches with food • 25cm in length • Mucosa contains gastric juice glands- 1.5 litres produced daily • when empty, the mucosa is wrinkled and when the stomach fills with food the wrinkles disappear • Physically churns and mixes food to produce chyme • Gastric juice contains:Pepsin: a type of protease enzyme responsible for breaking down proteins into their smaller components peptides.Hydrochloric acid: keeps the stomach acidic as pepsin works best in an acidic environment. It also aids in dissolving minerals and kills micro organisms.Mucus: lubricates food

  4. The layers of tissue that make up the alimentary canAL • 1. The innermost lining of the esophagus is the mucosa, its function is to produce mucus to lubricate the incoming bolus. • 2. The next layer is composed of connective tissue (the submucosa) that contains nerves and blood vessels. • 3. After that comes a layer of circular muscle fibres that run in rings around the circumference of the esophagus. • 4. Beneath this is a layer of longitudinal muscle fibres that run up and down the length of the esophagus. • 5. The final outer layer is a thin layer of connective tissue.

  5. Revision questions • Name the 5 layers of tissue that make up the esophagus and stomach wall (and the entire GI) • What is the process called that contracts the oesophagus in a wave- like motion, in order to move food down to the stomach? • Which three substances make up gastric juice? Name the importance of each

  6. Links of interest • The esophagus • http://www.medtropolis.com/vbody.asp • The stomachhttp://www.bbc.co.uk/science/humanbody/body/factfiles/stomach/stomach.shtml

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