Digestive System the Gastrointestinal System Extends From

Digestive System

The gastrointestinal system extends from the mouth to the anus. It includes the oral cavity, esophagus, stomach, duodenum, small and large intestine, rectum and the anus. The digestive system also includes other organs responsible for digestion, namely the liver, gall bladder and the pancreas. By way of the peristaltic movements of the tract and enzymes secreted from these organs, food is digested and absorbed; to be either stored in the body, or used as energy. Nerves and blood vessels also play a major role in the digestive system. (Kumar, 2007)

Diseases of the digestive system are a major cause of morbidity and mortality worldwide. Approximately ten percent of all general practitioner consultations in the United Kingdom are due to digestive problems, with a majority resulting from diarrhea. In the United States, approximately $85.5 billion are spent on GI and liver diseases. (Boon, 2006) The highest cost per year is 9.3 billion dollars for Gastro esophageal Reflux disease (GERD), followed by gallbladder disease (5.8 billion),and 4.8 billion for colorectal cancer. Infective diarrhea and malabsorption are a major cause of hospital admissions and death amongst developing countries. Moreover, this is the most common site for harboring cancerous growth. (RS, JE, & M, 2002)

Recently, due to the advancements in medical technology and extensive research being carried out, there has been an improvement in the diagnostic capability, greatly decreasing the period of illness. Sophisticated radiological tests, diagnostic and therapeutic endoscopy have also replaced the need for invasive surgeries under general anesthesia, greatly reducing the cost of medical treatment through the years. (Kumar, 2007)

The oral cavity is responsible for chewing food and for the secretion of saliva, which contains amylase responsible for digestion. Inflammatory or ulcerative lesions in this region cause pain and difficulty in chewing. Cancers of the oral cavity and tongue can also develop due to smoking or infection with human papilloma virus. The five-year survival rate, despite surgery, range from ninety one percent for lip cancer to about thirty percent for cancers of the base of the tongue, pharynx and the floor of the mouth. (Kumar, 2007)

Lesions of the esophagus vary from lethal carcinomas to bland esophagitis. Neurological dysfunction can also lead to defective or insufficient peristalsis. Congential disorders, such as stenosis, atresia, fistula, mucosal webs or diverticulas can also occur. All of these disorders produce symptoms of dysphagia. A decreased tone of the lower esophageal sphincter can cause regurgitation of gastric contents, leading to heart burn. Less commonly, hematemesis and melena are evidence of severe inflammation, ulceration or laceration of the esophageal mucosa. Life threatening hematemsis can result from the rupture of esophageal varices. (Kumar, 2007)

The stomach secretes enzymes for digestion and contains a high PH responsible for destruction of pathogens. Gastritis, which can either be autoimmune or infective, is a common condition of this organ. Gastric ulceration and carcinomas can result from chronic gastritis, however the prevalence has decreased due to active screening of H.pylori which is the causative organism for gastritis. Often, there is discomfort or pain in the epigastric region, with weight loss. Neoplasms can cause dysphagia when they are located in the cardia or cause obstructive symptoms if located at the pylorus. (Kumar, 2007)

The liver is an organ which maintains homeostasis of the body. It is responsible for the production of bile used to for digestion of fats and processes dietary amino acids, lipids and carbohydrates. Jaundice can result as a symptom due to defective bile production. Hepatitis is a common inflammatory reaction of the liver due to viral infections. The pancreas produces enzymes for digestion of fats proteins and carbohydrates. Diabetes is a common illness due to insufficiency of this organ. Fatal pancreatitis and hepatitis can also occur if diagnosis and treatment are not initiated appropriately. The gall bladder is the organ where bile is stored. Gall stones affect 10 to 20% of individuals in Western countries. (Kumar, 2007)

The small intestine contains multiple villi, which aids in absorption through its increased surface area. Certain enzymes responsible for digestion are also secreted on the mucosal surface. Many conditions, such as infections, inflammatory diseases and tumors, usually affect the small and large intestine together. Cancer of the colon is the second most common carcinoma, out of which, adenocarcinoma comprise the majority. Complications of intestinal disease can lead to ischemia of the bowel, obstruction or adhesions with surrounding peritoneal structures. A gastroenterologist acquires special training and deals with diseases of the digestive system. (Kumar, 2007)