Gastritis Essays - Digestive System, RTT, Abdomen, Stomach

Gastritis The stomach is a rounded, hollow organ located just inferior to the diaphragm in the left part of the abdominal cavity. This organ is about 10 inches long with a diameter that varies, depending on how much you eat in a given time. Although the stomach can hold up to 4 liters when totally filled, it can expand or decrease thanks to deep, mucous-coated folds in the stomach called rugae. Rugae both allow the stomach to stretch in order to accommodate large meals and help to grip and move food during digestion. As the stomach received food from the esophagus, it performs several functions: Acts a temporarily holding area for food, Secretes gastric acid and enzymes, which it mixes with the food, causing chemical digestion, Regulates the rate at which the now partially digested food enters the small intestine, Absorbs small amounts of water and substances on a very limited basis( although the stomach does not absorb alcohol). It takes about 4 hours for the stomach to empty after a meal. Liquids and carbohydrate pass through fairly quickly. Protein takes a little more time, and fats take even longer, usually form 4 to 6 hours (Colbert, 2009) The stomach can be divided into four regions based on shape and function: The esophagus connects to the stomach at a small region called the cardia. The cardia is a narrow, tube-like region that opens up into the wider regions of the stomach. Due to its location, that why indigestion is sometimes referred to as heartburn. Within the cardia is the lower esophageal sphincter, a band of muscle tissue that contracts to hold food and acid inside of the stomach. The cardia empties into the body of the stomach, which forms the central and largest region of the stomach. Superior to the body is a dome shaped region known as the fundus. The fundus temporarily holds the food as it enters the stomach. Inferior to the body is a funnel shaped region known as the pylorus. Most of the digestive work of the stomach is performed in the pyloric region. There is also the region were chyme must pass to another door, the pyloric sphincter. The pyloric sphincter controls the flow of partially digested food (known as chyme) out of the stomach and into the duodenum. The muscular action of the stomach works like a cement mixer and is achieved by the three layers of muscle found in its walls. One layer is longitudinal, one is circular, and the third is oblique in orientation. This arrangement of muscles enables the stomach to churn food as it mixes with gastric juices excreted by gastric glands from gastric pits in the columnar epithelial lining of the stomach as well as to work the food toward the pyloric sphincter through the muscle activity; peristalsis. (Rizzo, 2007)With the combined efforts of the muscles and gastric juices, both physical and chemical digestion occurs. A healthy stomach is capable of producing up to three liters a day of the vital gastric acid required for digestion Gastric juice is a general term for a combination of hydrochloric acid, pepsinogen and mucus, approximately 1,500 milliliters of gastric juice a day. (Gary A. Thibodeau, 2010) The stomachs activity is controlled by the parasympathetic nervous system, particularly the vagus nerve. Once the vagus nerve is stimulates, the stomachs motility (churning action) increases. There are three phases of gastric juice production cephalic, gastric and intestinal phase. The cephalic phase of gastric secretion occurs in response to stimuli received by the sensesthat is, taste, smell, sight, and sound. The gastric phase, where two-thirds of the gastric juices are secreted as the food moves into the stomach. As the food moves in, the stomach begins to distend. As the stomach distends, it sends signals back to the brain, which fires a reply to the gastric glands to step up their work. As chyme is formed, peristalsis pushes it through the pyloric sphincter to the first part of the small intestine the duodenum. The entry of the food into the duodenum begins the intestinal phase. (Rizzo, 2007)As the duodenum distends and senses the acidity of chyme, intestinal hormones are released that cause gastric glands on the stomach to decrease gastric juice