The+Stomach+by+Marisa+&+Kat


__The Stomach__


The stomach is a muscular, elastic, pear shaped organ which is located between the esophagus and the intestines. It changes shape according to body position and also the amount of food inside. It is about 12 inches long and 6 inches wide at it's widest point, and can hold about 1 quart in the average adult.

Functions: 
 * 1) To kill parasites and bad bacteria that may have been ingested. (Some bacteria may be helpful, such as acidophilus and bifidus).
 * 2) Break down the food into smaller particles, this mainly done by the acids, enzymes, and "churning motions". This makes the food easier to digest.
 * 3) Act as a temporary storage to hold the food. Then slowly release it into the lower parts of the digestive system.

The stomach may produce up to 2.2 to 3 liters of gastric acid (a.k.a. stomach acid) per day; basic secretion levels are usually highest during the evening. Other functions include absorption of: ions, water, and lipid soluble compounds like alcohol, aspirin, and caffeine.

Anatomy Of The Stomach:  The stomach lies between the esophagus and duodenum, which is the first part of the small intestine. Two smooth muscle valves (a.k.a sphincters) keep the contents of the stomach contained; they are the esophageal sphincter, which divides the tract above, and the pyloric sphincter, which divides the stomach from the small intestine. The stomach is surrounded by parasympathetic and orthosympathetic plexuses, which are a network of blood vessels and nerves, they regulate both the secretion and motor activities of the muscles.

**The stomach is divided into four sections:** **Cardia**- Where the contents of the esophagus empty into the stomach. **Layers of Stomach Wall from Inside to Outside:** **Mucosa**- The first main layer; Consists of an epithelium, the lamina propria, which is composed of loose connective tissue and has gastric glands underneath and a thin layer of smooth muscle called muscularis mucosae.
 * Fundus**- Formed by the upper curvature of the organ.
 * Body or corpus**- the main, "central", region.
 * Pylorus or Antrum**- Lower section of the organ that facilitates emptying the contents into the small intestine.
 * Submucosa**- Lays under the mucosa, and consists of fibrous connective tissue. The Meissner's plexus is located in this layer.
 * Muscularis Externa**- Under the submucosa, has three layers of smooth muscle rather than two. **Inner Oblique Layer**-- Creates the motion that churns and physically breaks down the food. Only layer that is not seen in any other digestive system organs. Has thicker skin cells in it's walls and produces stronger contractions than the fundus.
 * Middle Circular Layer**-- The pylorus is surrounded by a thick circular muscular wall which is tonically constricted forming a pyloric sphincter, which controls the movement of chyme into the duodenum.
 * Outer Longitudinal Layer**-- Auerbach's plexus is found between this layer and the middle circular layer . **Serosa**- Under the muscularis externa, consists of layers of connective tissue continuous with the peritoneum.

Movement Through the Stomach: The movement and flow of chemicals into the stomach are controlled by the //autonomic nervous system// and by the various //digestive system hormones//. 
 * The Hormones:**
 * 1) **Gastrin**- Causes and increase in the secretion of HCl, pepsinogen and intrinsic factor from the parietal cells in the stomach. Causes increased motility in the stomach. Gastrin is released by the "G-cells". Inhibited by a pH normally lower than four, as well as the hormone //somatostatin//.
 * 2) **Cholecystokinin**- CCK, has most effect on the gall bladder, but it also decreases gastric emptying and increases release of pancreatic juice which is alkaline and neutralizes chyme.
 * 3) <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">**Secretin-** Produced in the small intestine, effects the pancreas mostly, but it also diminishes acid secretion in the stomach.
 * 4) <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">**Gastric Inhibitory Peptide-** Decreases gastric acid and motility.
 * 5) <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">**Enteroglucagon-** Decreases both gastric acid and motility.
 * 6) <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">**Glycogen-** Produced in the liver, affects liver and level of glucose in the stomach.

<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Other than gastrin, all the hormones act to turn off the action of the stomach. This is in response to food products in the liver and gall bladder, which have not yet been absorbed. The stomach needs only to push food into the small intestine when the intestine is not busy. While the intestine is full and still digesting food, the stomach acts as storage for food.

<span style="font-family: 'Arial Black',Gadget,sans-serif; font-size: 200%; color: rgb(128, 0, 0);">Stomach Disorders:
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">**Cyclic Vomiting Syndrome:** When a person goes through times of severe nausea and vomiting, but then has normal periods of health in between. There is no apparent cause, but can be treated with medications.
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">**Gastritis:** Inflammation of the lining of the stomach; may be either acute or chronic.
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">**Gastroparesis:** A disorder in which the stomach takes too long with emptying it's contents. This occurs when nerves to the stomach are damaged or all together stop working.
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">**Heartburn:** A painful burning feeling in your chest or throat. This is caused when stomach acid backs up into the esophagus. Pregnancy, certain foods, alcohol and some medications may bring about heartburn. Treatment is important because reflux can damage the esophagus over time.
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">**Hiatus Hernia:** The protrusion of the stomach above the diaphragm. May be a congenital disorder or the result of trauma.
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">**Indigestion:** A feeling of discomfort or burning in your upper abdomen; you may also feel bloated and nauseated, belch a lot or even throw up. You may get indigestion from eating too much, too fast, fatty foods, or while stressed. Smoking, drinking too much alcohol, certain medications, or having ongoing stress may also lead to indigestion or make it worse. However, indigestion may be associated with a more serious digestive system problem like an ulcer or GERD.
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">**Peptic Ulcer:** A sore in the lining of your stomach or duodenum; burning stomach pain is the most common symptom. Peptic Ulcers occur when the acids that help digest food damage the walls of your stomach or duodenum. The most common is caused by a bacteria called //Helicobacter Pylori//; another cause would be the long term use of non-steroidal, anti-inflammatory medications, (aspirin and ibuprofen). Stress and spicy foods do not cause ulcers, but do make them worse.

The Stomach Crossword Puzzle

code Across 2. A sore in the lining of the stomach or duodenum. 3. Section of the stomach formed by the upper curvature. 5. The shape of the stomach. 8. Lower section of the stomach. 9. Found in the outer longitudinal layer. 10. One of the functions of the stomach is to kill these and bad bacteria. 11. Hormone produced in the small intestine. 13. First main layer of the stomach wall. 14. Cardia is where the contents of this empty into the stomach. 15. The stomach may produce up to these many liters of gastric acid per day. 16. Another name for the stomach's smooth muscle valves. 17. This nervous system controls the flow of chemicals into the stomach. 18. Located in the submucosa layer. 19. Hormone that effects the level of glucose in the stomach. Down 1. A protrusion of the stomach above the diaphragm. 4. The hormone gastrin causes and increase in secretion of this. 5. The stomach is surrounded by this kind of plexus. 6. Indigestion is a feeling of discomfort or burning in your...abdomen. 7. Inflammation of the stomach wall. 12. Hormone that has the greatest effect on the gall bladder. code Across: 2. Peptic Ulcer 3. Fundus 5. Pear 8. Pylorus 9. Auerbach's Plexus 10. Parasites 11. Secretin 13. Mucosa 14. Esophagus 15. Three 16. Sphincter 17. Autonomic 18. Meissners Plexus 19. Glycogen Down: 1. Hiatus Hernia 4. HCl 5. Parasympathetic 6. Upper 7. Gastritis 12. Cholecystokonin

<span style="font-family: 'Times New Roman',Times,serif; font-size: 150%;">Sources: [|Digestive Disorders] [|Mamas Health: The Stomach] [|MedlinePlus: Stomach Disorders] [|Wikipedia: The Stomach]

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