The Physiology of the Gastrointestinal Tract (GIT (complete).pptx

For the sake of study

1. The Physiology of the Gastrointestinal Tract (GIT) Presented by: Dr. Amna Aftab Alvi PHYSIOTHERAPIST BSPT (UAJK) TDPT (KMU) Research Associate/ Junior Lecturer UAJK Female Physiotherapist Gulshan Polyclinic Member APPA

2. Organization of the GIT GIT is a tube running through the body from mouth to anus. The alimentary canal : mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum and anal canal. Associated glands : salivary glands, pancreas, liver and gall bladder.

3. GENERAL FUNCTION OF GASTROINTESTINAL TRACT: Gastrointestinal physiology is the branch of human physiology that addresses the physical function of the gastrointestinal (GI) tract. The principal functions of the gastrointestinal tract are to digest and absorb ingested nutrients, and to excrete waste products of digestion.

4. Functions of the GIT The primary function of the alimentary tract is to break down food and to provide the body with a continual supply of water , electrolytes and nutrients . To achieve this function, the GIT must perform the following processes: Ingestion Motility: mixing and propulsion Secretion Digestion (Mechanical and chemical) Absorption Excretion

5. Ingestion Ingestion is defined as  the consumption of any food, drink, or other substance. Motility Gastrointestinal (GI) motility is defined  as the coordinated contractions and relaxations of the muscles of the GI tract which help to transfer food from mouth to large intestine and then out of the body. Secretion GI secretions include  enzymes and fluids which aid in the liberation of nutrients from food , as well as mucus which facilitates transport of food down the alimentary tract.

6. Digestion: It is  the process of mechanically and enzymatically breaking down food into substances for absorption into the bloodstream . The food contains three macronutrients that require digestion before they can be absorbed: fats, carbohydrates, and proteins. Absorption Absorption is  the process by which the products of digestion are absorbed by the blood to be supplied to the rest of the body . Excretion: The separation and throwing off of waste materials or toxic substances from the cells and tissues of body.

7. The Enteric Nervous System: The gastrointestinal tract has a nervous system of its own called the enteric nervous system also known as intrinsic nervous system. It is referred as second brain of our body which contains approximately100 - 300 million neurons. It lies entirely in the wall of the gut, beginning in the esophagus and extending all way to the anus. This system especially controls gastrointestinal movements and secretion.

8. The enteric nervous system is composed mainly of two plexuses. 1) an outer plexus called myenteric plexus and 2) an inner plexus called submucosal plexus . The myenteric plexus controls mainly the gastrointestinal movements by secreting the excitatory neurotransmitter substances like acetylcholine. The submucosal plexus controls mainly gastrointestinal secretion and local blood flow.  Extrinsic Nervous System: The extrinsic nervous system is  the nervous system that is external to the bowel  and it consists of autonomic, sensory and motor nerves. 

9. Extrinsic P arasympathetic nervous system Sympathetic nervous  system Parasympathetic •releases ACh •increases motility  and tone •relaxes the sphincters •increases the secretions from stomach. S ympathetic •brakes of GIT •releases  epinephrine •fight or flight •decrease motility and tone Inhibits secretions  from stomach • decreases blood flow • decreases peristalsis • decreases absorption.

10. CONTROL OF GASTROINTESTINAL MOBILITY AND SECRETIONS:

11. Functional Types of Movements in the Gastrointestinal Tract: Two types of movements occur in the GIT: Propulsive movements, muscular contractions which cause food to move forward along the gastro-intestinal tract at an appropriate rate to accommodate digestion and absorption, and 2) Mixing movements, which keep the intestinal contents thoroughly mixed at all times. 

12. Propulsive Movements- Peristalsis The basic propulsive movement of the GIT is peristalsis. A contractile ring appears around the gut and then moves forward. This ring spreads along tube.  Any material in front of the contractile ring is moved forward.  Mixing movements- Segmentation Rhythmic contractions in adjacent sections create segmentation contractions, which are mixing movements.

13. Patterns of GI motility: Type of contraction Organ/structure • TONIC CONTRACTIONS upper and lower esophageal sphincters pyloric valve ileocecal valve internal anal sphincter • PROPULSIVE PERISTALSIS esophagus lower 2 thirds of stomach small intestine rectum REVERSE PERISTALSIS (anti propulsion) proximal colon

14. Patterns of GI motility: (cont.) Type of contraction Organ/structure MASS MOVEMENTS (which are propulsive and are more prolonged than the peristaltic movements of the small intestine) ascending, transverse and descending colon • NON PROPULSIVE SEGMENTATION small intestine • HAUSTRATION (segmentation contraction create bulges) ascending, transverse and descending colon

15. SECRETION: Exocrine glands (e.g., salivary, digestive (pancreas, liver)) discharge their products through ducts. These products ( digestive juices) consist of: water electrolytes specific organic constituents important for digestive process (enzymes, bile salts, mucus) Endocrine glands or ductless, glands (e.g., pituitary, thyroid, adrenal) secrete substances known as hormones directly into the bloodstream rather than through ducts for regulation of the GI system.

16. Functions of GI secretion are: Protective Digestive Protective function: • bicarbonate (neutralization of acid produced by bacteria and gastric reflux) • antibacterial (lysozyme) • secretory immunoglobulin (IgA) • mouth hygiene • facilitates speaking

17. Digestive function: lubrification of food bolus for swallowing. dissolving substances for taste mechanism. Provide enzymatic machinery for degradation of nutrients.(-amylase (= ptyalin), lingual lipase) Provide factors to facilitate absorption. (e.g. bile salts, intrinsic factor)

18. Salivary glands : In humans saliva is secreted by: Parotid (largest serous salivary gland) (25% secretion) Submandibular (submaxillary) (70% secretion) Sublingual ( s mallest of the 3 salivary glands, almond-shaped)  (only 5% secretion) Composition of Saliva: Water (99.5%) Electrolytes (Na, K, Ca, HCO3) Proteins • mucin (glycoproteins) • digestive enzymes (salivary amylase) • protective proteins (secretory IgA )

19. MASTICATION SWALLOWING

20. MASTICATION: It is also known as chewing. The teeth are admirably designed for chewing. The anterior teeth incisors provide a strong cutting action and the posterior teeth molars a grinding action. Most of the muscles of chewing are innervated by the motor branch of the fifth cranial nerve and the chewing process is controlled by nuclei in the brain stem.

21. Much of the chewing process is caused by chewing reflex. It consists of up-and-down and side-to-side movements of the lower  jaw  that assist in reducing particles of solid  food , making them more easily swallowed. Reasons for chewing food are to soften the tough fibers and to expose them to enzymes necessary for digestion.

22. SWALLOWING: It is also known as deglutition. Normal swallow consists of a set of behaviors resulting in food movement from the mouth to the stomach. It is a reflex controlled from the brain stem. The swallow is often described as containing four stages: T he oral preparation stage; Voluntary phase The oral stage; Voluntary phase T he pharyngeal stage; Involuntary phase and the E sophageal stage; Involuntary phase

23. The Oral preparation stage: In the oral preparatory phase, food is taken into the mouth, manipulated into a bolus, and held there momentarily as it is prepared for transport. Preparation may include chewing, incorporating saliva into the bolus to from a smooth and cohesive mass, breaking the bolus into small parcels, and positioning it for transport through the oral cavity. Oral Stage: In the oral stage, the bolus is propelled posteriorly towards the oropharynx.

24. P haryngeal stage . A pharyngeal swallow response is initiated in the brainstem, setting into motion a series of airway-protective (closure of the vocal folds, and the epiglottis) and bolus-propulsive (opening of the upper esophageal sphincter; propulsion of the bolus by the base of the tongue into the pharynx) events. It all happens in less than 6 seconds. Esophageal Phase: The esophageal phase is initiated by relaxation of the upper esophageal sphincter at the top of the esophagus that allows the bolus to propel through the peristaltic action toward the stomach via the lower esophageal sphincter. As the food approaches the lower esophageal sphincter, the muscle fibers comprising the valve relax and food passes into the stomach.

25. Once through the lower esophageal sphincter, the valve again tenses to prevent food and stomach acid from back flowing out of the stomach and into the esophagus—an occurrence known as reflux. Normal esophageal transit time is 8 to 1 0 seconds.

26. Cranial Nerves Role in Swallowing: The trigeminal (V) cranial nerve, the facial (VII) cranial nerve, the glossopharyngeal (IX) cranial nerve, motor fibers from the vagus (X) cranial nerve, the hypoglossal (XII) cranial nerve all play direct or indirect role in swallowing.

27. SWALLOWING DISORDERS : DYSPHAGIA : The word   dysphagia is derived from the Greek phagia (to eat) and dys (with difficulty). Difficulty in swallowing. • Eating becomes unjoyful. • It refers to the sensation of food being obstructed in the food passage anywhere from the mouth to the stomach.

28. 2. GASTROESOPHAGEAL REFLUX DISEASE: The mucosal damage produced by the abnormal reflux of gastric contents (stomach acid) into the esophagus .

29. STOMACH

30. STOMACH: ANATOMY OF STOMACH: Stomach is the most dilated part of the gastrointestinal tract. • J shaped • Length- 25cms Capacity- 1.5 to 2 Lt It has 5 parts- • Cardia • Fundus • Body • Antrum • Pyloru s

31. GASTRIC CELLS: PARIETAL CELL Present only in fundus of stomach. • Secrete HCL & intrinsic factor. HCL- main component of gastric juice which kills microorganisms present in food. Activate pepsinogen(inactive) to Pepsin(active) required for protein breakdown & digestion. INTRINSIC FACTOR- required for absorption of vitamin B12.

32. 2. CHIEF CELL • Present  only in fundus. • Secrete PEPSINOGEN- inactive form of pepsin, required for protein b reakdown & digestion. GASTRIC GLANDS: Gas tric glands  are located beneath the gastric pits within gastric mucosa. Gastric glands are named according to their location. • Cardiac glands- found in cardia of stomach • Fundic glands- found in fundus of stomach • Pyloric glands- located in antrum & pylorus.

33. FUNCTIONS  OF THE STOMACH: Storage of food until it is processed. Mixing of food with gastric secretion and forms a semisolid mixture called Chyme. Slow emptying of chyme from stomach into small intestine at a suitable rate for better digestion and absorption.

34. GASTRIC ACID SECRETION PHASES OF GASTRIC  SECRETION: • Cephalic phase • Gastric phase • Intestinal phase CEPHALIC PHASE: It  occurs even before food enters the stomach. • It results from sight, smell, thought of food. It accounts for 30% of gastric secretion. • Neurogenic signal transmit through vagus nerve. 2. GASTRIC PHASE: Once   food enters the stomach, it causes stimulation of gastric juice secretion. • It accounts for 60% of gastric secretion.

35. 3 . INTESTINAL PHASE : Presence  of food in duodenum or upper part of small intestine , stimulate stomach to secrete small amount of gastric juice. • This is due to release of gastrin in duodenal mucosa. • It accounts of 10% of gastric secretion. REGULATION OF GASTRIC   ACID SECRETION: • Stimulated by – acetylcholine , gastrin, histamine. • Inhibited by- presence of food in small intestine. presence of acid, fat, protein breakdown product. secretin. gastric inhibitory peptides VIP somatostatin

36. GI MOTILITY &   GI EMPTYING: When food enters stomach the fundus and upper part of body relax and accommodate the food. • Peristalsis begins in the lower portion of body, mixing and grinding the food and permitting chyme pass through pylorus and enter the duodenum. • In regulation of gastric emptying the antrum, pylorus, upper duodenum function as unit. • Contraction of antrum is followed by sequential contraction of the pyloric region and duodenum. REGULATION OF GASTRIC  MOTILITY & EMPTYING: • The rate at which the stomach empties into duodenum depends on the type of food ingested. • Food rich in carbohydrate empties fast • Protein rich food leaves slowly. • And fat containing food leaves stomach very slowly.

37. PERISTALSIS: Peristalsis is   the radial symmetrical contraction and relaxation of muscles that propagates in a wave down the tube. • In stomach the co ordinated contraction of circular & longitudinal muscle result in movement of chyme in forward direction. • Presence of food in stomach result in gastric secretion and peristalsis. PACEMAKER FOR GASTRIC  PERISTALSIS: • The source of myogenic activity in GIT has been tracked down to INTERSTITIAL CELLS OF CAJAL, which act as pacemaker, that generates slow wave in smooth muscle. INTERSTITIAL CELL OF  CAJAL: • These are the type of interstitial cells found in GIT. • Myenteric interstitial cell of cajal (ICC MY) serve as a pacemaker bioelectrical slow wave potential that leads to contraction of smooth muscle. • These contraction of smooth muscle result in peristalsis.

38. DISORDERS OF STOMACH ACHLORHYDRIA: • Failure of stomach to secrete HCL, despite maximum stimulation. • It also prevents the function of pepsin. 2. GASTRIC ATROPHY: • Normally  gastric secretion contains Intrinsic factors. In case of atrophy there is reduced intrinsic factors which r esults in decrease absorption of vitamin B12 in ileum. • This may lead to pernicious anemia.

39. 3. GASTRITIS: Inflammation of gastric mucosa. • May be associated with H. Pylori Upper abdominal pain, nausea, vomiting, indigestion, heart burn. • Diagnosis can be done by endoscopy + biopsy • Rx antibiotic, PPI 4. GASTRIC ULCER: • Break  in the inner lining of stomach. • Due to H. Pylori infection or NSAIDS. • Presented with upper abdominal pain and dyspepsia. • Dx by upper GI endoscopy + biopsy. • Rx antibiotic, PPI

40. SMALL INTESTINE

41. SMALL INTESTINE: The small intestine extends from the pylorus to the ileocecal junction. • It is about 6 meter long. • It is approximately 2.5–3 cm in diameter .

42. REGIONS OF THE  SMALL INTESTINE: SMALL INTESTINE: The small  intestine is divided into • Duodenum • Jejunum • Ileum. THE DUODENUM: Greek  word- dudekadaktulos – means twelve fingers • The duodenum is a short structure (about 20–25 cm long) continuous with the stomach and shaped like a "C". • It lies above the level of the umbilicus, opposite 1st, 2nd and 3rd lumbar vertebrae .

43. THE DUODENUM : • It  receives gastric chyme from the stomach, together with digestive juices from the pancreas (digestive enzymes) and the gall bladder (bile). • The digestive enzymes break down proteins and bile and emulsify fats. • The duodenum contains Brunner's glands, which produce a mucus-rich alkaline secretion containing bicarbonate. • These secretions, in combination with bicarbonate from the pancreas, neutralizes the stomach acids contained in gastric chyme.

44. THE JEJUNUM : • The  jejunum is the midsection of the small intestine, connecting the duodenum to the ileum. • It is about 2.5 m long, and contains the plicae circulares, and villi that increase its surface area. • Products of digestion (sugars, amino acids, and fatty acids) are absorbed into the bloodstream here.

45. THE ILEUM: • The  final section of the small intestine. • It is about 3 m long, and contains villi similar to the jejunum. • It absorbs mainly vitamin B12 and bile acids, as well as any other remaining nutrients. • The ileum joins to the cecum of the large intestine at the ileocecal junction.

46. THE INTESTINAL VILLI: The intestinal villi are finger –like projections of mucous membrane, just visible to the naked eye. • They give the surface of the intestinal mucosa a velvety appearance. • They are large and numerous in the duodenum and jejunum, but are smaller and fewer in the ileum.

47. INTESTINAL GLANDS: • These are simple tubular glands distributed over the entire mucous membrane of the jejunum and ileum. • They open by small circular apertures on the surface of mucous membrane between the villi. • They secrete digestive enzymes and mucus.

48. INTESTINAL SECRETIONS: • The  principal constituents of intestinal secretions are water, mucus and mineral salts. • Most of the digestive enzymes in the small intestine are contained in the enterocytes of the walls of the villi. • Digestion of carbohydrate, protein and fat is completed by direct contact between these nutrients and the microvilli and within the enterocytes.

49. FUNCTIONS OF THE  SMALL INTESTINE: • Onward movement of its contents by peristalsis, which is increased by parasympathetic stimulation. • Secretion of intestinal juice, also increased by parasympathetic stimulation. • Completion of chemical digestion of carbohydrates, protein, and fats in the enterocytes of the villi. Protection against  infection by microbes that have survived the antimicrobial action of the hydrochloric acid in the stomach. • Secretion of the hormones cholecystokinin( cck ) and secretin. • Absorption of nutrients.

50. INTESTINAL MOTILITY: The movements in the small intestine can be divided into:  Propulsive movements.  Contraction ring.  Receptive relaxation.  Peristaltic contractions.  Local constrictive contractions.  Mixing movements.  Movements of villi.  Segmental contractions.  Pendular movements .

51. LARGE INTESTINE DEFECATION

52. The Large Intestine “The  Colon ” The Colon : The colon (large intestine) is a distal part of the gastrointestinal tract, extending from the caecum to the anal canal. The colon averages 150cm in length. Movements sluggish (18-24 hours) The parts of the large intestine form a frame for the small intestine. Histology: Simple columnar • Deep intestinal glands • crypt Absence of villi • Presence of goblet cells

53. REGIONS OF LARGE INTESTINE: Anatomically, it can be divided into following parts :– Caecum » Vermiform appendix • Ascending Colon • Transverse Colon • Descending Colon •Sigmoid Colon Rectum Anal canal (Anus)

54. THE CECUM: The sac like  caecum (L. caecus , blind) is the 1st part of the large intestine. The caecum is a broad blind pouch and is 5 to 7 cm in length. • It is located inferior to the ascending colon. T he vermiform appendix opens into its medial aspect.  THE VERMIFORM APPENDIX: This is a narrow, worm-shaped blind tube (L vermis, worm + forma, form). • It is variable in length, averaging 8 cm. It is relatively longer in infants and children than in adults. ASCENDING COLO N: The ascending colon travels up the right side of the abdomen.

55. TRANSVERSE COLON: It  is the longest (20 inch/50 cm in length) and most mobile part of the large intestine. DESCENDING COLON: The descending colon is a section of the large intestine that passes downward. SIGMOID COLON, ( MESOCOLON)  , (PELVIC   COLON): The sigmoid colon is around 15 inches (37.5 cm) long and attaches the descending colon with the rectum. It’s S shaped and therefore its name, sigmoid colon (G. Sigma = S-shaped alphabet). RECTUM: Straight muscular tube. ANAL CANAL: Internal anal sphincter (smooth muscle)  External anal sphincter (skeletal muscle)

56. Functions of the  Large Intestine: Absorption of water & electrolytes from chyme. (Proximal) Storage of fecal matter prior to defecation. (Distal) Absorb vitamins produced by bacteria. ELECTROLYTE ABSORPTION Na+ absorption:  Mucosa of the large intestine has a large capability for Na absorption (active)  Electrochemical gradient created by this absorption causes Cl absorption as well.  Na ions are far more absorbed here than in the small intestine.

57. Secretions of Large Intestine: Mucus secretion Crypts No villi No enzymes Moderate amount of bicarbonate ions Functions of Large Intestine Mucus secretion Protection Adherent medium for holding fecal material Protection from bacterial activity (taking place inside feces) Barrier to acids formed in feces (mucus + bicarbonate)

58. LARGE INTESTINE MOTILITY. Movements include: Slow wave activity. (SWA)  Frequency of SWA gradually increase down the Large Intestine.  9/min – ileocecal valve to 16/min at sigmoid colon. 2. Haustral shuttling.   Similar to segmental contractions  Circular muscle contractions– circular rings  Longitudinal muscles contractions – portion between rings bulge in bag like sacs called Haustrations.  Disappears within 60 sec.

59.  Functions –  Mixing: M ix up the contents of the colon, exposing them to the mucosa, hence facilitating absorption.  Propulsion. Peristalsis Progressive contractions preceded by receptive wave of relaxation. Take up to 42 hrs. to travels up to colons. 3. Mass movements.   Special types of peristaltic contractions in colon only.  3-4 times a day after a meals.  Contraction of the smooth muscle over a large area distal to the constriction.  Force fecal matter into rectum to initiate defecation reflex.

60. DEFECATION OR EGECTION : •  Defecation is the voluntary process in which feces are excreted from the gastrointestinal tract through the large intestine “especially the distal colon”. • The defecation is done by interaction with enteric neurons, autonomic nervous , and central nervous system. • Defecation Reflexes: Is done by Intrinsic reflex mediated by the local enteric nervous system in the rectal wall. Stimuli for   initiation defecation process: 1. Distention of the rectal wall by feces. 2. Gastrocolic reflex “ reflex peristalses that travels from stomach to large intestine ” _ drinking a coffee, or water, or food. 3. Irritation by chemical or toxins in the wall of the large intestine.

61. Relaxation of internal anal sphincter: It causes intense and powerful peristaltic {propulsive} movement forcing the feces containing the distal colon, sigmoid, and rectum toward the anus • Also parasympathetic sends signals to the myenteric plexus for inhibiting the constriction of the internal anal sphincter and relaxing it. Relaxation the external anal   sphincter(-) Valsalva maneuver: T he brain also sends signals to the respiratory and abdominal muscles in a process called Valsalva maneuver. • Valsalva maneuver fortified the defecation by: Deep inspiration. Closure of glottis. Sudden contraction of abdominal muscle wall.

62. Disorders of large intestine: Some of the disorders of large intestine include: Appendicitis. Diarrhea Definition: Loss of fluid & Electrolytes via Stools Causes:↑ GIT Motility , Irritation (e.g. by bacteria). Hemorrhoids: Vein enlargement or inflammation. Colon Cancer. Polyps: E xtra tissue growing in the colon that can become cancerous. Hernia Cholera Crohn's disease: Inflammatory bowel disease Intestinal ischemia Ulcerative colitis (Ulcers of the colon and rectum)

63. The Liver, Gallbladder and Pancreas

64. THE LIVER : Dark/Reddish Brown, vital organ. Largest internal organ and largest gland. Lies on the right side of the abdominal cavity beneath the diaphragm. In males it weighs from 1.4 to 1.6 kilograms, in females from 1.2 to 1.4 kilograms. Macroscopic/Gross structure: At the macroscopic level, the liver is divided into two major lobes, (left and right) and two smaller lobes (quadrate and caudate)

65. Microscopic structure: At the microscopic level, the liver consists of hexagonal shaped functional units called hepatic lobules. These consist mostly of hepatocytes (the most common type of liver cell). HEPATO’ means liver, ‘CYTE’ means cell. Hepatocytes perform metabolic and secretary functions. Hepatocytes do not do phagocytosis. Phagocytosis is done by macrophages present in the liver called KUPFFER cells.

66. FUNCTIONS OF THE  LIVER: “A healthy liver is a sign of a healthy body” Carbohydrate M etabolism. Protein Metabolism. Secretion of Bile: Composed of Water – Cholesterol – Bile pigments (Bilirubin and Biliverdin). 

67. Liver: Bile Secretion:   The liver is an accessory digestive organ that produces bile, an alkaline fluid containing cholesterol and bile acids, which helps the breakdown of fat. The gallbladder, a small pouch that sits just under the liver, stores bile produced by the liver which is later moved to the small intestine to complete digestion. Bile salts are absorbed in the small intestine and recycled.

68. LIVER PATHOLOGY : Among the many diseases of the liver, some are: 1. Jaundice: A common sign of a damaged liver is jaundice, a yellowness of the eyes and skin. This happens when bilirubin, a yellow breakdown product of red blood cells, builds up in the blood. 2. Hepatitis (inflammation of the liver), caused mainly by various viruses but also by some poisons, autoimmunity, or hereditary conditions. 3. Cirrhosis is the formation of fibrous tissue in the liver, replacing dead liver cells. The death of the liver cells can for example be caused by viral hepatitis, alcoholism or contact with other liver-toxic chemicals. 4. Hemochromatosis , a hereditary disease causing the accumulation of iron in the body, eventually leading to liver damage. 5. Cancer of the liver . 6. Wilson's disease , a hereditary disease which causes the body to retain copper .

69. THE GALLBLADDER: In vertebrates   the gallbladder ( cholecyst , gall bladder or biliary vesicle) is a small pear shaped organ where bile is stored, before it is released into the small intestine. Humans can live without a gallbladder. The gallbladder is a hollow organ that sits just beneath the right lobe of the liver The biliary apparatus collects bile from the liver, stores it in the gall bladder, and transmits it to the duodenum.   

70. FUNCTIONS OF THE  GALL BLADDER: 1 . Storage of bile, and its release into the duodenum when required. 2. Absorption of water, and concentration of bile. Bile may be concentrated as much as ten times. 3. The normal gall bladder also absorbs small amounts of a loose bile salt cholesterol compound. 4. It regulates pressure in the biliary system by appropriate dilatation or contraction.

71. GALLSTONES: Estimated that 20 million people in USA have gallstones. Deposition of cholesterol or bilirubin in the gallbladder or in common biliary duct. Cholesterol stones are the common type in Western countries. About 1/3 of patients will get episodes of pain in the epigastric region. Treatment is cholecystectomy (gall bladder removal) or sometimes endoscopic approaches to remove stones from common biliary duct or sphincter of Oddi. Consequence of gall bladder removal is inability to concentrate bile, which affects fat absorption, and fatty meals may need to be avoided.

72. THE PANCREAS: The pancreas is   both an Exocrine and Endocrine gland. Exocrine secretions • Almost  all of the pancreas (95%) consists of exocrine tissue. • The function of the exocrine pancreas is to produce pancreatic juice containing about 20 enzymes that digest carbohydrates, proteins and fats. • The pancreas secretes 1500–3000 mL of isosmotic Alkaline fluid (pH >8) (bicarbonate + water) per day. The exocrine cells in the pancreas play a central role in the production of digestive enzymes

73. Enzyme Secretion: The acinar cell is highly concerned with the secretion of pancreatic enzymes. Enzymes are produced and secreted in excess. The pancreatic secretions provide the enzymes needed to effect the major digestive activity of the gastrointestinal tract and provide an optimal pH for the function of these enzymes. 2. Endocrine secretions • Distributed  throughout the gland are groups of specialized cells called the pancreatic islets (islets of Langerhans). • The islets have no ducts so the hormones diffuse directly into the blood.

74. Pancreatic endocrine cells  regulate carbohydrate, fat, protein metabolism: Alpha cells – glucagon Beta cells – insulin Delta cells – gastrin and somatostatin F cells – pancreatic polypeptide Disorders of pancreas: Pancreatic   inflammatory disease may be classified as (1) Acute pancreatitis or (2) Chronic pancreatitis. Pancreatic Cancer. Pancreatic Cysts. Cystic fibrosis, a genetic disorder in which thick, sticky mucus can also block tubes in your pancreas.

75. GIT HORMONES VOMITING ACID PEPTIC DISEASE

76. GIT HORMONES INTRODUCTION : Earlier it was believed that r egulatory mechanisms were controlled by the nervous system. Later numerous chemicals in the name of hormones were found. Hormones play an integral role in most of the regulatory mechanisms in our body. The gastrointestinal hormones are the hormones secreted in GI tract. Largest endocrine organ  Enteric endocrine system. Total about 30 GIT hormones. These are biologically active polypeptide. Main function is: 1. To regulate the GIT secretion 2. To regulate the movement of GI tract.

77. Classification of GIT HORMONES:

78. VOMITING: It is a means by which the GIT rids itself of its contents when almost any part of the upper GIT becomes excessively irritated, over distended or over excited(anti peristalsis) The chemoreceptor trigger zone(CTZ): It is a small area located bilaterally on the floor of 4 th ventricle in/above area prostema which on excitation causes vomiting.

79. The vomiting act: A deep breath Raising of hyoid bone and larynx to open UES Closing of glottis Lifting of soft palate to close posterior nares Strong downward contraction of diaphragm along with abdominal wall muscles Stomach squeeze, LES relaxes and expulsion of gastric contents upward through the esophagus Excitation of CTZ: Electrical stimulation artificially, motion sickness, Drugs: apomorphine, morphine, digitalis derivatives, Mechanical stimulation Treatment: Anti emetics

80. ACID PEPTIC DISEASE: Acid peptic disorders include a number of diseases, whose etiology can be linked to gastric secretions. Gastroesophageal reflux disease, (GERD) and peptic ulcer disease, are two most common and well-defined disease states. GERD.  Damage to esophageal tissues from stomach acid backing up into your esophagus can lead to spasm or scarring and narrowing of your lower esophagus. Etiology: Lower esophageal sphincter   incompetence, Transient lower esophageal sphincter relaxation, Obesity: contributing factor in GERD Typical Features: Heartburn,  Regurgitation, Coughing  and/or wheezing, Hoarseness Treatment Pharmacologic Therapy:  Antacids, H2 receptor antagonists: Ranitidine, Cimetidine, Famotidine. Nizatidine, Proton pump inhibitors: Omeprazole, Rabeprazole, Esomeprazole,

81. 2. PEPTIC ULCER: An open sore on the lining of the digestive tract/ an excoriated area of the mucosa caused by the digestive action of gastric juice Peptic ulcers include gastric ulcers and duodenal ulcers Causes Major cause is bacterium Helicobacter pylori (H. pylori) , that burrows into stomach membranes, allowing stomach acids and digestive juices to create an ulcer Smoking Excessive acid- abnormal mucus secretion Psychogenic factors that increase acid production Symptoms include Burning pain, indigestion, nausea, vomiting hematemesis, and melena (dark, tarry stool) Usual treatment methods are Antacids, a balanced diet, decreased stress, and avoidance of irritants such as alcohol, fried foods, tobacco and caffeine If H. pylori bacteria are present, treatment with antibiotics usually cures the condition PPIs( esomeprazole etc ), H 2 RB (cimetidine etc ) Severe cases, surgery is performed to remove the affected area ( gastrectomy)