THE MOUTH AND THE STOMACH - The basic plan, the peritoneum...

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The basic plan, the peritoneum and the stomach Hyoid bone: The only free floating bone of the axial skeleton near the epiglottis. Recap of Deglutition (The act of Swallowing) Tongue pushes masticated (chewed) food towards oropharynx Uvula closes off nasopharynx. This is important to prevent food from getting into the nasal cavity. The epiglottis closes off the entrance to the larynx. Pharyngeal muscles will push the bolus of food down the upper esophageal sphincter
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As shown in the diagram on the right hand side, the esophagus is completely collapsed when no food is present. When a bolus of food needs to pass through, the esophagus expands. Deglutition continued After the food has passed the upper esophageal sphincter, it will move in an involuntary fashion towards the stomach. The first 1/3 of the esophagus is under voluntary control via the pharyngeal muscles (skeletal muscles). Below the 1/3 point, the muscles moving food to the stomach are smooth muscles (involuntary). When the bolus of food passes the diaphragm, it must pass through the lower esophageal sphincter before entering the stomach. The lower esophageal sphincter prevents items from the stomach from entering the esophagus. These acidic refluxes can be damaging to the mucosal lining of the esophagus. The Lower esophageal sphincter must relax to allow the bolus to enter the stomach. The lower esophageal sphincter, like the upper esophageal sphincter is not really a “sphincter”. The lower esophageal sphincter depends on the force exerted by the diaphragm to keep the esophagus closed. The movement of food occurs via the longitudinal and circular muscles First the circular muscles contract to prevent food from flowing backwards. Next the longitudinal muscles contract to propel the food downwards along the esophagus.
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When the lower esophageal sphincter does not work properly: There are instances when the stomach can herniate through the diaphragm. When this happens, the lower esophageal sphincter no longer exists! As a result, acid reflux is likely to occur, causing damage to the lower esophagus. Hiatal Hernia Antacids can be administered to neutralize the acidic content of the stomach. Antacids are simply bicarbonate pills. As a result, they neutralize the HCl that is causing problems. The basic plan of the GI system Mucus Membrane: Epithelium: The innermost layer of the mucosal membrane. In the stomach, small intestine and the large intestine, this layer is composed of columnar epithelium. In other regions such as upper portions of the GI and near the anus, it becomes stratified squamous epithelium. The epithelium here differs from the one on the skin as it is not keratinized. Lamina Propria: The layer above the epithelium. It’s the middle layer. Connective tissue comprising of blood vessels, nerves and glands.
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THE MOUTH AND THE STOMACH - The basic plan, the peritoneum...

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