Anatomy and physiology of GI system and Diagnostic techniques

anatomy and physiology of gastro intestinal system

1. THE DIGESTIVE SYSTEM PRESENTED BY: HARSH RAMAN M.Sc (N) 1 st Year Roll No-1914703

2. Introduction: The digestive system is the collective name used to describe the alimentary canal, some accessory organs and a variety of digestive process that takes place at different levels in the canal to prepare food eaten in the diet for absorption .

3. THE DIGESTIVE SYSTEM The digestive tract is more than 10 meters (30 feet) long from one end to the other. It is continuous starting at the mouth, passing through the pharynx, oesophagus (25 cm long) , the stomach, the small and large intestine and ending in the rectum (12.5-15 cm long) & finally into the anus.

4. Human digestive system

5. FUNCTION OF THE DIGESTIVE SYSTEM: INGESTION DIGESTION ABSORPTION ELIMINATION

6. INGESTION It involves Placing the food into the mouth. Chewing the food into smaller pieces (mastication). Moistening of the food with salivary secretion. Swallowing the food (deglutition).  

7. DIGESTION During digestion, food is broken down into small particles by the grinding action of the gastro-intestinal tract ( GIT ) and then degraded by the digestive enzyme into usable nutrients.

8. ABSORPTION During absorption, nutrients, water and electrolytes are transported from the GIT to the circulation.  

9. ELIMINATION Food substances that have been eaten but cannot be digested and absorbed are excreted from the alimentary canal as feces by the process of defecation.

10. ORGANS OF DIGESTIVE SYSTEM Alimentary Tract Mouth Pharynx Esophagus Stomach Small intestine Large intestine Rectum and anal canal

11. Accessory organs OF DIGESTIVE SYSTEM Three pairs of salivary gland The pancreas The liver & biliary tract.

12. STRUCTURE OF ALIMENTAY CANAL The walls of the alimentary tract are formed by 4 layers of tissues.

13. Adventitia or serosa This is the outer most layer and in the thorax it consists of losse fibrous tissue and in the abdomen the organs are covered by a serous membrane ( serose ) called peritoneum.

14. Peritoneum It is the largest serous membrane of the body. It has two layers Parietal layer- which lines the abdominal valve Visceral layer- it cover the organs within the abdominal and pelvic cavities.

15. 2. Muscle layer It consist of two layer of smooth (voluntary)muscle Contraction and relaxation of these muscle layers occur in waves, which push the contents of the tract onwards. This type of contraction of smooth muscle is called “peristalsis”. Onward movement of the content of the tract is controlled at various points by sphincters, which are thickened rings of circular muscle contraction of sphincter regulates forward movement and prevent the backflow in the tract.  

16. 3. Sub mucosa: This layer consists of loose connective tissue, blood vessels and lymphatics.

17. 4. Mucosal layer: It consists of three layers of tissues. Mucus membrane Lamina propria Muscularis mucosa Mucus membrane: It has three main function- protection, secretion, and absorption.

18. Mucosal layer: Lamina propria : it consisting of loose connective tissue, which supports the blood vessels that nourish the inner epithelial layer, and varying amounts of lymphoid tissue that has a protective function. Muscularis mucosa: it is a thin outer layer of smooth muscles that provides involutions of the mucosa layer, gastric glands, and villi .

19. The walls of the alimentary tract

20. MOUTH (ORAL CAVITY) The mouth or oral cavity is lined by mucous membrane, consisting of stratified squamous epithelium containing mucus secreting glands.

21. BOUNDARIES OF ORAL CAVITY Anteriorly : by lips Posteriorly : it is continuous with oropharynx Laterally: by muscles of the cheeks Superiorly: by bony hard palate & muscles of soft palate Inferiorly: by soft tissue of floor, mouth & tongue.

22. TOUNGUE It is a voluntary muscular structure. It is attached by its base to the hyoid bone & by frenulum to the floor of the mouth. Its superior surface consists of stratified squamous epithelium, with little projection called as papillae, containing taste buds.

23. Functions Of Tounge The term plays an important role in chewing ( mastication), swallowing( deglutition), speech & taste.

24. TEETH The teeth are embedded in sockets of the mandible and maxilla. Each person has two sets of teeth, the temporary & permanent teeth. TEMPORARY (DECIDUOUS) - They are 20 in number, 10 in each jaw. They begin to erupt at the age of six months & all are present by the age of 24 months. Shapes- molars 2/2, premolars, canine 1/1, incisors 2/2.

25. TEETH PERMANENT TEETH- They are 32 in number & begin to replace the temporary teeth in the sixth year of age. It is usually completed by the 24 th year. Shapes- molars 3/3, premolars 2/2, canine 1/1, incisors 2/2.

26. Functions of teeth: Incisor and canine teeth have cutting surface & are used for biting off pieces of foods. Whereas the premolar & molar have broad & flat surfaces & are used for chewing food.

27. Structure of tooth The shape of the different teeth vary, the structure is the same & consists of The crown- the part that protrudes from the gum. The root- the part embedded in the bone. The neck- slightly narrowed reason where the crown merges with the root.

28. SALIVARY GLAND Salivary gland releases their secretion into ducts that lead into the mouth. There are 3 main pairs Parotid gland The submandibular glands Sublingual glands

29. PAROTID GLAND These are situated one on each side of the face just below the external acoustic meatus . Each gland has a parotid duct opening into the mouth at the level of the second upper molar tooth. B) SUBMANDIBULAR GLAND These lie one on each side of the face under the angle of the jaw. The two submandibular ducts open on the floor of the mouth, one on each side of the frenulum of the tongue.

30. C) SUBLINGUAL GLANDS: These glands lie under the mucous membrane of the floor of the mouth in front of the sub- mandibular glands. These have numerous small ducts that open into the floor of the mouth.

31. STRUCTURE OF THE SALIVARY GLANDS: The glands are all surrounded by the fibrous capsule. They consist of a number of lobules made up of small acini lined with secretory cell. The secretion are poured into ductiles that join upto form larger ducts leading into the mouth. BLOOD SUPPLY: Arterial supply is by various branches from the external carotid artery and venous drainage is into the external jugular veins.

32. COMPOSITON OF SALIVA: It about 1.5 liters of saliva is produced daily and it consist of Water mineral salts An enzyme- salivary amylase Mucous Lysozyme Immunoglobulins Blood clotting factors

33.   FUNCTIONS OF SALIVA: Chemical digestion of polysaccharides : Saliva contains the enzyme amylase that begins the breakdown of complex sugar, including starch, reducing them to the disaccharides maltose. The optimum pH for the action of salivary amylase is 6.8. salivary pH ranges from 5.8 -7.4 depending upon the rate of flow. Lubrication of food : Dry food entering the mouth is moistened and lubricated by saliva before it can be made into a bolus ready for swallowing.

34. FUNCTIONS OF SALIVA: Cleaning and lubricating : an adequate flow of saliva is necessary to clean the mouth and to keep it soft, moist and pliable. It help to prevent damage to the mucous memvrane by rough or abrasive food. Taste: The taste buds are stimulated only by chemical substances in solution & therefore dry fruits only stimulated the sense of taste after through mixing with saliva.  

35. PHARYNX: Pharynx is divided for descriptive purpose into three parts, the nasopharynx , oropharynx and laryngopharynx . The nasopharynx is important in respiration. The oropharynx & laryngopharynx are passage common to both the respiratory and the digestive system. Food passes from the oral cavity into the pharynx then to the esophagus below, with which it is continuous.

36. BLOOD SUPPLY OF PHARYNX The blood supply to the pharynx is by several branches of the facial arteries. The venous drainage is into the facial veins and internal jugular veins. NERVE SUPPLY: This is from the pharyngeal plexus and consist of parasympathetic and sympathetic nerve. Parasympathetic supply is mainly by the glossopharyngeal and vagous nerves and sympathetic from the cervical ganglia.

37. OESOPHAGUS: The oesophagus is about 25 cm long and about 2cmm in diameter and lies in the median plane in the thorax in front of the vertebral column behind the trachea and the heart

38. STRUCTURE OF OESOPHAGUS: There are four layers of tissue .As the oesophagus is almost entirely in the thorax the outer covering ,the adventitia ,consist of elastic fibrous tissue that attaches the oesophagus to the surrounding structure . The proximal third is lined by stratified squamous epithelium and distal third by columnar epithelium .the middle third is lined by a mixture of the two.

39. Blood supply Arterial - The thoracic region is supplied mainly by the paired oesophagus arteries ,branches from the thoracic aorta. The abdominal region is supplied by branches from the inferior phrenic arteries and the left gastric branches of the celiac artery.

40. Venous drainage From the thoracic region venous drainages is in to the azygos and hemiazygos vein. There is a venous plexus at the distal end that links the upward and downward venous drainages, the general and portal circulation .

41. STOMACH The stomach is J- shaped dilated portion of the alimentary tract situated in the epigastric ,umbilical and left hypochondriac regions of the abdominal cavity.

42. Structure of the stomach The stomach is continuous with the oesophagus at the cardiac sphincter and with the duodenum at the pyloric sphincter . It has two curvatures ,the lesser curvature is short Just before the pyloric sphincter it curve upwards to complete the J- shape .

43. Structure of the stomach Where the oesophagus join the stomach the anterior region angles acutely upwards ,curves downwards forming the greater curvature and then slightly upwards the pyloric sphincters. The stomach is divided in to three regions :the fundus ,the body and the antrum . At the distal end of the pyloric antrum is the pyloric sphincter, is relaxed and open ,and when the stomach contains food the sphincter is closed.

44. Organs associated with the stomach Anteriorly - left lobe of liver and anterior abdominal wall. Posteriorly – abdominal aorta, pancreas , spleen,left kidney and adrenal glands.

45. Organs associated with the stomach Superiorly- diaphragm, oesophagus and left lobe of liver. Inferiorly- transverse colon and small intestine To the left- diaphragm and spleen. To the right- liver and duodenum.

46. Walls of the stomach The four layers of tissue that comprise the basic structure of the alimentary canal are found in the stomach but with some modifications.

47. Muscles layer- This consists of three layers of smooth muscles fibers An outer layer of longitudinal fibers A middle layer of circular fibers. An inner layer of oblique fibers.

48. Blood supply Arterial supply to the stomach is by the left gastric artery , and branch of the coeliac artery ,the rights gastric artery and the gastroepiploic arteries. Venous drainages is through veins of corresponding names into the portal veins .

49. Functions of the stomach These includes Temporary storage allowing time for the digestive enzyme, pepsin, to act. Enzyme digestion- pepsin convert protein to peptides . Mechanical breakdown- the three smooth muscle layer able the stomach to act as a churn, gastric juice is added and the contents are liquefied to chyme . Motility & secretion are increased by parasympathetic nerve stimulation.

50. Functions of the stomach Limited absorption of water, alcohol & some lipid soluble drugs. Known, specific defense against microbes- provided by hydrochloride acid into gastric juice. Production & secretion for intrinsic factor needed for absorption of vitamin b12 in the terminal ileum. Regulation of the passage of gastric contents into the duodenum. Secretion of the gastric hormones .

51.   SMALL INTESTINE The small intestine can be divided into 3 major regions: The  duodenum  is the first section of intestine that connects to the pyloric sphincter of the stomach. It is the shortest region of the small intestine, measuring only about 10 inches in length.

52. SMALL INTESTINE The  jejunum  is the middle section of the small intestine that serves as the primary site of nutrient absorption. It measures around 3 feet in length. The  ileum  is the final section of the small intestine that empties into the large intestine via the ileocecal sphincter. The ileum is about 6 feet long and completes the absorption of nutrients that were missed in the jejunum.

53. SMALL INTESTINE The small intestine (or small bowel) is the part of the gastrointestinal tract. The small intestine is a long, highly convoluted tube in the digestive system that absorbs about 90% of the nutrients from the food we eat. It is given the name “small intestine” because it is only 1 inch in diameter, making it less than half the diameter of the large intestine. The small intestine is, however, about twice the length of the large intestine and usually measures about 10 feet in length.

54.   The small intestine It is made up of four layers of tissue Mucosa -The  mucosa  forms the inner layer of epithelial tissue and is specialized for the absorption of nutrients from chyme . Sub mucosa layer   -Deep to the mucosa is the  sub mucosa layer  that provides blood vessels, lymphatic vessels, and nerves to support the mucosa on the surface.

55. layers of small intestine Muscularis layer -Several layers of smooth muscle tissue form the  muscularis layer  that contracts and moves the small intestines.   Serosa - it  forms the outermost layer of epithelial tissue that is continuous with the mesentery and surrounds the intestines.

56. FUNCION OF SMALL INTESTINE 1. Onward movement of its contents by peristalsis, which is increased by parasympathetic stimulation. 2. A secretion of intestinal juice, also increase by parasympathetic stimulation. 3. Completion of chemical digestion of carbohydrate, protein and fat in the electrolytes of the villi . 4. Secretion of the hormones cholesystokinin (CCK) . 5. Absorption of nutrients.

57. LARGE INTSTINE It consists of the following parts: 1. Caecum 2. The ascending colon 3. The transverse colon 4. The descending colon 5. The pelvic or sigmoid colon 6. The Rectum 7. The anal canal

58. LARGE INTSTINE Large intestine, posterior section of the intestine, consisting typically of four regions: the  cecum , colon, rectum, and anus.  The large intestine is wider and shorter than the small intestine(approximately 1.5 meters, or 5 feet it begins in the right iliac region of the pelvis, just at or below the waist, where it is joined to the end of the small intestine. It then continues up the abdomen, across the width of the abdominal cavity, and then down to its endpoint at the anus.

59. LARGE INTSTINE The caecum is the first part of the colon and is a dilated portion which has a blind lower end and is continuous above with the ascending colon. Just below the junction of the two, the ileocaecal valve opens. This valve is a sphincter and prevents the caecal contents passing back into the ileum.

60. LARGE INTSTINE The Vermiform appendix is a fine tube closed at one end, which opens out of the caecum , about 2 cm below the ileo-caecal valve. It is usually about 13 cm (5 inches) long and has the same structure as the walls of the colon but contains more lymphoid tissues.

61. LARGE INTSTINE The ascending colon passes upwards from the caecum to the level of the liver where it bends acutely to the left of at the right colic flexure to become the transverse colon. The transverse colon is about 50 cm in length and passes across the abdomen to the under surface of the spleen. Where it forms the left colic flexure, by bending acutely downwards to become the descending colon.

62. LARGE INTSTINE The descending colon is about 25 cm in length and passes down the left side of the abdomen to the inlet of the lesser pelvis, where it becomes the sigmoid colon. The pelvic or sigmoid colon has an S-shaped curve in the pelvis and it continues downwards to become the rectum. The Rectum is about 12 cm long and is a slightly dilated part of the colon. It leads from the pelvic colon and terminates in the anal canal.

63. The anal canal It is a short canal about 3.8 cm (1 1 /2 inches) long in adults and leads from the rectum to the exterior. There are two sphincter muscles which controls the anus- The internal sphincter surrounds the upper the three quarters of the canal and consists of smooth muscle fibers. The external spinster and consists of striated muscle. It is the tone of these sphincters which keep the anal canal and the anus Closed.  

64. STRUCTURE In structure, the large intestine consists of the same four layers of the alimentary canal as described above with a few modifications. The arrangement of the longitudinal muscle fiber is modified in the colon. They do not form a smooth continuous layer of tissues, but are collected into three bands called taenia coli situated at regular intervals round the colon.

65. STRUCTURE These bands are shorter than the other layers of the large intestine and so produce a typical puckered or sacculated appearance. In the sub mucous layer , there are more lymphoid tissues than in any other part of the alimentary canal. The mucus lining of the colon and the upper part of the rectum contains large number of goblet cells, which secrets mucus.

66. FUNCTIONS OF LARGE INTESTINE Functions are: 1. Absorption : In the colon, water, mineral, salts and some drugs are absorbed into the blood capillaries. 2. Secretion: Colon has only one secretion, mucin which lubricates the feces and facilitates their passage through the rectum and anus.

67. FUNCTIONS OF LARGE INTESTINE 3. Digestion: Many bacteria are present here which act on various food residues which have not been digested or absorbed in the small intestine. 4. Excretion: Excess of calcium, iron and drugs of heavy metals, such as bismuth, are excreted from the walls of the large intestine and mix with the feces.

68. FUNCTIONS OF LARGE INTESTINE Defecation: Defecation is the process of emptying the rectum or the passage of feces out of the body. This is achieved by the gastro-colic reflex, which occurs by reflex action with the infant whereas in adults, is under the control of the will and is carried out in response to the desire to empty the bowel produced by distension of the rectum with feces.

69. PANCREAS The pancreas is a pale grey gland waiting about 60gms. It is about 12-15 cm long & is situated in the epigastric & left hypochondriac region of the abdominal cavity. It consist of a broad head , a body & a narrow tale. The head lies in the curve of the duodenum, the body behind the stomach & the tale lies in the front of the left kidney & just reaches the spleen.

70. PANCREAS The pancreas is both an endocrine and exocrine gland. Exocrine Endocrine Description Large number of lobes, each drained by a tiny duct Ducts eventually unite to form the pancreatic duct, which opens into the duodenum Groups of specialised cells (pancreatic islets/ islets of Langerhans ) with no ducts Hormones diffuse directly into the blood as glands have no ducts Function Production of pancreatic juice containing enzymes that digest carbohydrates, proteins and fats Secretes hormones, insulin and glucagon which are principally concerned with the regulation of blood glucose levels

71. LIVER Liver is the largest gland in the body, weighing between 1 and 2.3 kg. It is situated in the upper part of the abdominal cavity.

72. ORGANS ASSOCIATED WITH THE LIVER Superiorly & anteriorly - diaphragm and anterior abdominal wall. Inferiorly - stomach, bile ducts, duodenum, hepatic flexure of the colon, right kidney & adrenal gland Posteriorly - oesophagus, inferior vanacava , aorta, gall bladder, vertebral column & diaphragm. Laterally - lower ribs & diaphragm.

73. ORGANS ASSOCIATED WITH THE LIVER

74. LIVER Liver has four lobes. The two most obvious are the large right lobe & the smaller, wedge shaped left lobe. The other two, caudate and quadrate lobe, are area on the posterior surface. BLOOD SUPPLY The hepatic artery & the portal vein take blood to the liver. Venous return is by a variable number of the hepatic veins that leave the posterior surface & immediately enter the inferior vena cava just below the diaphragm.

75. STRUCTURE The lobes of the liver are made up of tiny functional units called lobules, which are just visible to the naked eye. Liver lobules are formed by cubicle- shaped cells, the hepatocytes . Between two pairs of columns of cells are sinusoids which containing a mixture of blood from the tiny branches of the portal vein and hepatic artery. This arrangement allows the arterial blood and portal venous blood to mix and close contact with the liver cells.

76. FUNCTIONS OF LIVER Carbohydrate metabolism Fat metabolism Protein metabolism Breakdown of erythrocytes and defense against microbes. Detoxification of drug & noxious substance- e.g., alcohol & toxin produced by microbes. Intoxification of hormones.

77. FUNCTIONS OF LIVER Production of heat Secretion of bile. Storage- the substances include Glycogen Fat soluble vitamins- A, D, E, K. Iron, copper Some water soluble vitamins- vitamin B12.

78. BILIARY TRACT BILE DUCTS The right & left hepatic ducts join to form the common hepatic duct just outside the portal fissure. The hepatic ducts passage downwards for about 3 cm where it is joined at an acute angle by the cystic duct from the gall bladder. The common bile duct is around 7.5 cm long and has a diameter of about 6mm.

79. STRUCTURE The walls of the bile ducts have the same layers of tissue as those described in the basic structure of the alimentary canal. In the cystic duct the mucous membrane lining is arranged in irregular circular folds, which have the effect of a spiral bulb.

80. GALL BLADDER The gall bladder is a pear-shaped sac attached to the posterior surface of the liver by connective tissue. It has a fundus or expended and, a body or main part and a neck, which is continues with the cystic duct.

81. STRUCTURE OF GALL BLADDER The gall bladder has the same layer of tissue as those described in the basic structure of the alimentary canal, with some modifications. There are three layers Peritoneum Cover only the inferior surface Muscle layer This is an additional layer of oblique muscle fiber. Mucus membrane Displays small rugae , when the gall bladder is empty that disappears when it is distended with bile.

82. FUNCTION OF GALL BLADDER Reservoir for bile. Concentration of the bile by upto 10- or 15- fold, by absorption of water through the walls of the gall bladder. Release of stored bile.

83. THE MAJOR DIGESTIVE ENZYMES AND SECRETION Enzymes that digest carbohydrates ENZYME SECRETION ENZYME SOURCE DIGESTIVE ACTION Ptyalin Salivary glands Starch to dextrin, maltose,glucose Amylase Pancreas and intestinal mucosa Starch to dextrin, maltose, gluccose Maltase Intestinal mucosa Dextrin to maltose and glucose Sucrase Intestinal mucosa Sucrose to glucose and fructose Lactase Intestinal mucosa Lactose to glucose and galactose

84. Enzymes that digest proteins ENZYME SECRETION ENZYME SOURCE DIGESTIVE ACTION Pepsin Gastric mucosa Protein to polypeptides Trypsin Pancreas Proteins and polypeptides to dipeptides and amino acids Aminopeptidase Intestinal mucosa Polypeptides to dipeptides and amino acids Dipeptidase Intestinal mucosa Dipeptides and amino acids Hydrochloric acid Gastric mucosa Protein to polypeptidase and amino acids

85. ENZYMES THAT DIGEST FATS ENZYME SECRETION ENZYME SOURCE DIGESTIVE ACTION Pharyngeal lipase Pharynx mucosa Triglycerides to fatty acids , diglycerides and monoglycerides Steapsin Gastric mucosa Triglycerides to fatty acids , diglycerides and monoglycerides Pancreatic lipase Pancreas Triglycerides to fatty acids , diglycerides and monoglycerides Bile liver Fat emulsification

86. Digestive Diagnostic Procedures

87. How is a digestive disorder diagnosed In order to reach a diagnosis for digestive disorders, a thorough and accurate medical history will be taken by your doctor, noting the symptoms you have experienced and any other pertinent information. A physical examination is also done to help assess the problem more completely. Some patients need to undergo a more extensive diagnostic evaluation, which may include laboratory tests, imaging tests, and/or endoscopic procedures. These tests may include any, or a combination of, the following:

88. Laboratory tests Fecal occult blood test. A fecal occult blood test checks for hidden blood in the stool. It involves placing a very small amount of stool on a special card, which is then tested in a laboratory. Stool culture. A stool culture checks for the presence of abnormal bacteria in the digestive tract that may cause diarrhoea and other problems..

89. Imaging tests Barium meal. During this test, the patient eats a meal containing barium allowing the radiologist to watch the stomach as it digests the meal. The amount of time it takes for the barium meal to be digested and leave the stomach gives the doctor an idea of how well the stomach is working and helps to detect emptying problems.

90. Colorectal transit study. This test shows how well food moves through the colon. The patient swallows capsules containing small markers which are visible on X-ray. The patient follows a high- fiber diet during the course of the test, and the movement of the markers through the colon is monitored with abdominal X-rays taken several times three to seven days after the capsule is swallowed

91. Computed tomography scan (CT or CAT scan) This diagnostic imaging procedure uses a combination of X-rays and computer technology to produce horizontal, or axial, images (often called slices) of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general X-rays.

92. Defecography Defecography is an X-ray of the anorectal area that evaluates completeness of stool elimination, identifies anorectal abnormalities, and evaluates rectal muscle contractions and relaxation. During the examination, the patient's rectum is filled with a soft paste that is the same consistency as stool. The patient then sits on a toilet positioned inside an X-ray machine, and squeezes and relaxes the anus to expel the solution. The doctor studies the X-rays to determine if anorectal problems occurred while the patient was emptying the paste from the rectum.

93. Lower GI (gastrointestinal) series (also called barium enema). A lower GI series is a procedure that examines the rectum, the large intestine, and the lower part of the small intestine. Barium is given into the rectum as an enema. An X-ray of the abdomen shows strictures (narrowed areas), obstructions (blockages), and other problems.

94. Magnetic resonance imaging (MRI). MRI is a diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body. The patient lies on a bed that moves into the cylindrical MRI machine. The machine takes a series of pictures of the inside of the body using a magnetic field and radio waves

95. Magnetic resonance cholangiopancreatography (MRCP). This test uses magnetic resonance imaging (MRI) to view the bile ducts. The machine uses radio waves and magnets to scan internal tissues and organs.

96. Oropharyngeal motility (swallowing) study This is a study in which the patient is given small amounts of a liquid containing barium to drink with a bottle, spoon, or cup. A series of X-rays is taken to evaluate what happens as the liquid is swallowed

97. Radioisotope gastric-emptying scan During this test, the patient eats food containing a radioisotope, which is a slightly radioactive substance that will show up on a scan. The dosage of radiation from the radioisotope is very small and not harmful, but allows the radiologist to see the food in the stomach and how quickly it leaves the stomach, while the patient lies under a machine.

98. Ultrasound Ultrasound is a diagnostic imaging technique that uses high-frequency sound waves and a computer to create images of blood vessels, tissues, and organs. Ultrasounds are used to view internal organs as they function, and to assess blood flow through various vessels. Gel is applied to the area of the body being studied, such as the abdomen, and a wand called a transducer is placed on the skin. The transducer sends sound waves into the body that bounce off organs and return to the ultrasound machine, producing an image on the monitor

99. Upper GI (gastrointestinal) series (also called barium swallow) Upper GI series is a diagnostic test that examines the organs of the upper part of the digestive system: the esophagus , stomach, and duodenum (the first section of the small intestine). Barium is swallowed and X-rays are then taken to evaluate the digestive organs.

100. Endoscopic procedures Colonoscopy. Colonoscopy is a procedure that allows the doctor to view the entire length of the large intestine (colon), and can often help identify abnormal growths, inflamed tissue, ulcers, and bleeding. It involves inserting a colonoscope , a long, flexible, lighted tube, in through the rectum up into the colon. The colonoscope allows the doctor to see the lining of the colon, remove tissue for further examination, and possibly treat some problems that are discovered.

101. Endoscopic retrograde cholangiopancreatography (ERCP). ERCP is a procedure that allows the doctor to diagnose and treat problems in the liver, gallbladder, bile ducts, and pancreas. The procedure combines X-ray and the use of an endoscope, a long, flexible, lighted tube. The scope is guided through the patient's mouth and throat, then through the esophagus , stomach, and duodenum . A tube is then passed through the scope, and a dye is injected that will allow the internal organs to appear on an X-ray.

102. Esophagogastroduodenoscopy (also called EGD or upper endoscopy). An EGD is a procedure that allows the doctor to examine the inside of the esophagus , stomach, and duodenum with an endoscope, which is guided into the mouth and throat, then into the esophagus , stomach, and duodenum. It is also used to take sample for biopsy.

103. Sigmoidoscopy . A sigmoidoscopy is a diagnostic procedure that allows the doctor to examine the inside of a portion of the large intestine, and is helpful in identifying the causes of diarrhea , abdominal pain, constipation, abnormal growths, and bleeding. A short, flexible, lighted tube, called a sigmoidoscope , is inserted into the intestine through the rectum. The scope blows air into the intestine to inflate it and make viewing the inside easier.

104. Other procedures Anorectal manometry . This test helps determine the strength of the muscles in the rectum and anus. Anorectal manometry is helpful in evaluating anorectal malformations and Hirschsprung's disease, among other problems. A small tube is placed into the rectum to measure the pressures exerted by the sphincter muscles that ring the canal.

105. Esophageal manometry This test helps determine the strength of the muscles in the esophagus . It is useful in evaluating gastroesophageal reflux and swallowing abnormalities. A small tube is guided into the nostril, then passed into the throat, and finally into the esophagus . The pressure the esophageal muscles produce at rest is then measured.

106. Esophageal pH monitoring. An esophageal pH monitor measures the acidity inside of the esophagus . It is helpful in evaluating gastroesophageal reflux disease . A thin, plastic tube is placed into a nostril, guided down the throat, and then into the esophagus . The tube stops just above the lower esophageal sphincter, which is at the connection between the esophagus and the stomach. At the end of the tube inside the esophagus is a sensor that measures pH, or acidity. The other end of the tube outside the body is connected to a monitor that records the pH levels for a 24- to 48-hour period. Normal activity is encouraged during the study, and a diary is kept of symptoms experienced , or activity that might be suspicious for reflux, such as gagging or coughing, and any food intake by the patient.

107. Capsule endoscopy This procedure is helpful in identifying causes of bleeding, detecting polyps, inflammatory bowel disease, ulcers, and tumors of the small intestine. A sensor device is placed on a patient's abdomen and a PillCam is swallowed. The PillCam passes naturally through the digestive tract while transmitting video images to a data recorder. The data recorder is secured to a patient's waist by a belt for eight hours. Images of the small bowel are downloaded onto a computer from the data recorder. The images are reviewed by a doctor on a computer screen. Normally, the PillCam passes through the colon and is eliminated in the stool within 24 hours.

108. Gastric manometry This test measures electrical and muscular activity in the stomach. The doctor passes a thin tube down the patient's throat into the stomach. This tube contains a wire that takes measurements of the electrical and muscular activity of the stomach as it digests foods and liquids. This helps show how the stomach is working, and if there is any delay in digestion