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Human Anatomy,  Second Edition McKinley & O'Loughlin   Chapter 26 Lecture Outline: Digestive System 26-
Overall Function: Disassembly Line <ul><li>hydrolysis </li></ul><ul><li>Polymers---------------->monomers </li></ul><ul><l...
General Structure and Functions  of the Digestive System <ul><li>The GI tract organs:  </li></ul><ul><ul><li>oral cavity <...
General Structure and Functions  of the Digestive System <ul><li>Accessory digestive organs:  </li></ul><ul><ul><li>often ...
Digestive System Functions  <ul><li>Ingestion </li></ul><ul><li>Digestion </li></ul><ul><ul><li>mechanical digestion   </l...
Oral Cavity (mouth) <ul><li>Entrance to the GI tract. </li></ul><ul><li>Initial site of mechanical digestion (via masticat...
Palate <ul><li>Anterior two-thirds of the palate is the bony hard palate), while the posterior one-third is the soft palat...
Tongue  <ul><li>An accessory digestive organ formed from skeletal muscle and covered with lightly keratinized stratified s...
Salivary Glands <ul><li>Collectively produce and secrete saliva. Most is produced during mealtime, but smaller amounts are...
The Parotid Glands <ul><li>Largest salivary glands .  </li></ul><ul><li>Near the ear, partially overlying the masseter mus...
The Submandibular Glands <ul><li>Inferior to the body of the mandible. </li></ul><ul><li>Produce most of the saliva (about...
The Sublingual Glands <ul><li>Inferior to the tongue and internal to the oral cavity mucosa. </li></ul><ul><li>Contribute ...
Functions of Saliva <ul><li>Moistens food and helps turn it into a semisolid bolus that is more easily swallowed.  </li></...
Teeth  <ul><li>Responsible for mastication (chewing), the first part of the mechanical digestion process. Increases the su...
Teeth <ul><li>Two sets of teeth develop and erupt during a normal lifetime.   </li></ul><ul><li>20 deciduous teeth , “milk...
<ul><li>About 5 inches long </li></ul><ul><li>Nasopharynx, oropharynx, and laryngopharynx </li></ul>Pharynx (Throat) 26-
Peritoneum and its Extensions <ul><li>Greater omentum (do not cut away!) </li></ul><ul><li>Lesser omentum </li></ul><ul><l...
General Histology of GI Organs <ul><li>From the esophagus through the large intestine is a tube of four concentric layers ...
Tunics of the Abdominal GI Tract <ul><li>See figure and model. </li></ul>26-
<ul><li>See figure. </li></ul>Phases of Swallowing 26-
Esophagus (Gullet) <ul><li>About 10 inches long </li></ul><ul><li>Muscular tube: 1/3 skeletal, 1/3 mixed, and 1/3 smooth <...
<ul><li>Reflux esophagitis is when acidic chyme refluxes into the esophagus, “heartburn” </li></ul><ul><ul><li>Poorly prot...
<ul><li>Stratified squamous in esophagus changes to simple columnar in stomach and stays simple columnar until the end of ...
<ul><li>Storage: 2-6 hours </li></ul><ul><li>Mixing and propulsion: break down bolus into  chyme </li></ul><ul><li>Protein...
<ul><li>Lack of vitamin B 12  leads to pernicious anemia. </li></ul>Gastrectomy 26-
<ul><li>Mucus (bile can produce gastritis) </li></ul><ul><li>Tight junctions </li></ul><ul><li>Rapid turnover (every three...
Peptic Ulcers <ul><li>Chronic, solitary erosion of the lining of the stomach (gastric ulcer) or small intestine (duodenal ...
Pyloric Sphincter <ul><li>Acts as a “gatekeeper” allowing only small amounts of chyme to enter duodenum at a time </li></u...
Small Intestine  <ul><li>Finishes the chemical digestion process and is responsible for absorbing   most of the nutrients ...
Small Intestine  <ul><li>The  duodenum is retroperitoneal , about 25 centimeters (10 inches) long and  originates at the p...
Small Intestine <ul><li>Almost all the digestion and absorption occur in the small intestine! </li></ul><ul><ul><li>90% of...
Small Intestine <ul><li>Mucosal Cavities lined with glandular epithelium </li></ul><ul><ul><li>Intestinal glands (crypts o...
Absorption in SI <ul><li>Active transport mainly into  villi  and then diffusion into capillaries then nutrients mainly go...
Large Intestine <ul><li>About 1.5 meters (5 feet) long and 6.5 centimeters (2.5 inches) wide. </li></ul><ul><li>Absorbs mo...
Movements in the Large Intestine <ul><li>Peristalsis - slower than before </li></ul><ul><li>Haustral churning: haustra fil...
<ul><li>No circular folds and no villi </li></ul><ul><li>Intestinal glands </li></ul><ul><ul><li>Microvilli present in abs...
Digestion in LI <ul><li>Chemical digestion is bacterial by  E .  coli  not enzymatic </li></ul><ul><li>Typically, feces ha...
Defecation <ul><li>Mass peristalsis from the sigmoid colon initiates defecation reflex (parasympathetic) </li></ul>26-
Appendicitis <ul><li>Perforation allows bacteria to enter the body and cause peritonitis, massive infection </li></ul><ul>...
<ul><li>Second most common type of cancer in US </li></ul><ul><ul><li>especially found in sigmoid colon, and distal descen...
Accessory Digestive Organs  <ul><li>The liver, about 3# (heaviest gland)   </li></ul><ul><ul><li>composed of four incomple...
Functions of The Liver   <ul><li>Produces bile, an emulsifier, not an enzyme. </li></ul><ul><ul><li>a greenish fluid that ...
<ul><li>Yellowish color to skin and mucous membranes  </li></ul><ul><li>Three major types </li></ul><ul><ul><li>Increase p...
Cirrhosis of the Liver <ul><li>Destruction of hepatocytes and their replacement with fibrous scar tissue  which compresses...
Cirrhosis of the Liver <ul><li>Complications if advanced: </li></ul><ul><ul><li>Jaundice (yellowing of skin and sclerae fr...
Accessory Digestive Organs <ul><li>Gallbladder  (about 3-4 inches long) </li></ul><ul><ul><li>concentrates bile produced b...
Gallstones <ul><li>Concentration of materials: cholesterol or calcium and bile salts  </li></ul><ul><li>Risk factors: obes...
Accessory Digestive Organs <ul><li>The biliary apparatus.  </li></ul><ul><ul><li>network of thin ducts that carry bile fro...
Accessory Digestive Organs <ul><li>Pancreas   </li></ul><ul><ul><li>mixed gland: both endocrine and exocrine functions  </...
Intestinal Disorders 26-
Celiac Disease <ul><li>Autoimmune disease of SI mucosa where villi are attacked.  </li></ul><ul><li>Gluten sensitive </li>...
Inflammatory Bowel Disease <ul><li>IBD: selective regions of the bowel become inflamed. Two autoimmune disorders. </li></u...
Inflammatory Bowel Disease <ul><li>Ulcerative colitis </li></ul><ul><ul><li>Similar age distribution and symptoms, but onl...
<ul><li>More common but not IBD, one in five have it. Cause and cure not known. Control by decreasing stress, changing one...
Other GI Problems <ul><li>Dental caries and periodontal disease </li></ul><ul><li>Eating disorders </li></ul><ul><li>Diver...
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Chapter 26, f 09

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Chapter 26, f 09

  1. 1. Human Anatomy, Second Edition McKinley & O'Loughlin Chapter 26 Lecture Outline: Digestive System 26-
  2. 2. Overall Function: Disassembly Line <ul><li>hydrolysis </li></ul><ul><li>Polymers---------------->monomers </li></ul><ul><li>< --------------- </li></ul><ul><li>dehydration </li></ul><ul><li>synthesis </li></ul>26-
  3. 3. General Structure and Functions of the Digestive System <ul><li>The GI tract organs: </li></ul><ul><ul><li>oral cavity </li></ul></ul><ul><ul><li>pharynx </li></ul></ul><ul><ul><li>esophagus </li></ul></ul><ul><ul><li>stomach </li></ul></ul><ul><ul><li>small intestine </li></ul></ul><ul><ul><li>large intestine </li></ul></ul><ul><li>A continuous tube about 30 feet (9–10 meters) from the mouth to the anus (longer in dead than living). </li></ul><ul><li>Smooth muscle in most of the GI tract wall pushes materials from one end to the other. </li></ul>26-
  4. 4. General Structure and Functions of the Digestive System <ul><li>Accessory digestive organs: </li></ul><ul><ul><li>often develop as outgrowths from the tube and are connected to the GI tract </li></ul></ul><ul><ul><li>assist the GI tract in the digestion of food. </li></ul></ul><ul><ul><li>teeth, tongue, salivary glands, liver, gallbladder, and pancreas </li></ul></ul>26-
  5. 5.
  6. 6. Digestive System Functions <ul><li>Ingestion </li></ul><ul><li>Digestion </li></ul><ul><ul><li>mechanical digestion </li></ul></ul><ul><ul><li>chemical digestion </li></ul></ul><ul><li>Propulsion </li></ul><ul><ul><li>peristalsis </li></ul></ul><ul><ul><li>segmentation (mainly churns and mixes) </li></ul></ul><ul><li>Secretion </li></ul><ul><li>Absorption </li></ul><ul><li>Elimination of wastes (defecation) </li></ul>26-
  7. 7.
  8. 8. Oral Cavity (mouth) <ul><li>Entrance to the GI tract. </li></ul><ul><li>Initial site of mechanical digestion (via mastication) and chemical digestion (via enzymes in saliva: salivary amylase and lipase). </li></ul><ul><li>Bounded by the teeth and lips, the oropharynx, the hard and soft palates, and the tongue </li></ul>26-
  9. 9.
  10. 10.
  11. 11. Palate <ul><li>Anterior two-thirds of the palate is the bony hard palate), while the posterior one-third is the soft palate, primarily skeletal muscle). </li></ul><ul><li>Extending inferiorly from the posterior part of the soft palate is the uvula. </li></ul><ul><li>When swallowing, the soft palate and the uvula elevate to close off the opening of the nasopharynx. </li></ul>26-
  12. 12. Tongue <ul><li>An accessory digestive organ formed from skeletal muscle and covered with lightly keratinized stratified squamous epithelium. </li></ul><ul><li>Manipulates and mixes ingested materials during chewing and </li></ul><ul><li>Helps compress these materials into a bolus . </li></ul><ul><li>Performs important functions in swallowing. </li></ul>26-
  13. 13. Salivary Glands <ul><li>Collectively produce and secrete saliva. Most is produced during mealtime, but smaller amounts are produced continuously. </li></ul><ul><li>Water makes up 99% of the volume of saliva. </li></ul><ul><li>Also contains a mixture of other components. </li></ul><ul><li>Three pairs of large, multicellular salivary glands </li></ul>26-
  14. 14. The Parotid Glands <ul><li>Largest salivary glands . </li></ul><ul><li>Near the ear, partially overlying the masseter muscle. </li></ul><ul><li>Produce about 25–30% of the saliva. </li></ul><ul><li>Site of mumps </li></ul>26-
  15. 15. The Submandibular Glands <ul><li>Inferior to the body of the mandible. </li></ul><ul><li>Produce most of the saliva (about 60–70%). </li></ul>26-
  16. 16. The Sublingual Glands <ul><li>Inferior to the tongue and internal to the oral cavity mucosa. </li></ul><ul><li>Contribute only about 3–5% of the total saliva. </li></ul>26-
  17. 17.
  18. 18.
  19. 19. Functions of Saliva <ul><li>Moistens food and helps turn it into a semisolid bolus that is more easily swallowed. </li></ul><ul><li>Moistens and cleanses the oral cavity structures. </li></ul><ul><li>First step in chemical digestion occurs when amylase in saliva begins to break down carbohydrates. Also a lingual lipase. </li></ul><ul><li>Contains antibodies and antibacterial lysozyme that help inhibit bacterial growth. </li></ul><ul><li>Watery medium into which food molecules are dissolved so taste receptors can be stimulated. </li></ul><ul><li>Produce about 1-1 1/2 liter/day. </li></ul>26-
  20. 20. Teeth <ul><li>Responsible for mastication (chewing), the first part of the mechanical digestion process. Increases the surface area and, therefore, increases the efficiency of digestive enzymes. </li></ul><ul><ul><li>Incisors and canines cut and tear </li></ul></ul><ul><ul><li>Premolars and molars crush and grind. </li></ul></ul><ul><li>A tooth has an exposed crown, a constricted neck, and one or more roots that anchor it the jaw. </li></ul><ul><li>Roots of the teeth fit tightly into dental alveoli. </li></ul>26-
  21. 21.
  22. 22.
  23. 23.
  24. 24. Teeth <ul><li>Two sets of teeth develop and erupt during a normal lifetime. </li></ul><ul><li>20 deciduous teeth , “milk teeth,” erupt between 6 months and 30 months after birth. </li></ul><ul><li>Replaced by 32 permanent teeth . </li></ul><ul><li>The last teeth to erupt are the third molars, “wisdom teeth,” in the late teens or early 20’s. May be absent. </li></ul><ul><li>Often the jaw lacks space and they may either emerge only partially or grow at an angle and become impacted. </li></ul>26-
  25. 25. <ul><li>About 5 inches long </li></ul><ul><li>Nasopharynx, oropharynx, and laryngopharynx </li></ul>Pharynx (Throat) 26-
  26. 26. Peritoneum and its Extensions <ul><li>Greater omentum (do not cut away!) </li></ul><ul><li>Lesser omentum </li></ul><ul><li>Falciform ligament </li></ul><ul><li>Round ligament </li></ul><ul><li>Mesentery </li></ul><ul><li>Mesocolon </li></ul><ul><li>Parietal peritoneum </li></ul><ul><li>Visceral peritoneum </li></ul>26-
  27. 27.
  28. 28.
  29. 29.
  30. 30. General Histology of GI Organs <ul><li>From the esophagus through the large intestine is a tube of four concentric layers called tunics: </li></ul><ul><ul><li>the mucosa </li></ul></ul><ul><ul><ul><li>superficial epithelium </li></ul></ul></ul><ul><ul><ul><li>lamina propria: areolar CT </li></ul></ul></ul><ul><ul><ul><li>muscularis mucosa </li></ul></ul></ul><ul><ul><li>the submucosa </li></ul></ul><ul><ul><ul><li>dense irregular CT </li></ul></ul></ul><ul><ul><ul><li>lymphatic tissue in some areas </li></ul></ul></ul><ul><ul><ul><li>mucin-secreting glands </li></ul></ul></ul><ul><ul><ul><li>many large blood vessels and lymphatic vessels </li></ul></ul></ul><ul><ul><ul><li>submucosal nerve plexus (Meissner plexus) </li></ul></ul></ul><ul><ul><li>the muscularis </li></ul></ul><ul><ul><ul><li>two smooth muscle layers typically except in the esophagus and stomach </li></ul></ul></ul><ul><ul><ul><li>myenteric nerve plexus (Auerbach plexus) </li></ul></ul></ul><ul><ul><li>the adventitia or serosa (covered by visceral peritoneum) </li></ul></ul>26-
  31. 31. Tunics of the Abdominal GI Tract <ul><li>See figure and model. </li></ul>26-
  32. 32. <ul><li>See figure. </li></ul>Phases of Swallowing 26-
  33. 33.
  34. 34. Esophagus (Gullet) <ul><li>About 10 inches long </li></ul><ul><li>Muscular tube: 1/3 skeletal, 1/3 mixed, and 1/3 smooth </li></ul><ul><li>2 sphincters regulate food in and out </li></ul><ul><li>Mucus lubricates </li></ul><ul><li>No digestion or absorption! </li></ul><ul><li>Esophageal hiatus through the diaphragm </li></ul><ul><li>Hiatal hernia </li></ul>26-
  35. 35.
  36. 36. <ul><li>Reflux esophagitis is when acidic chyme refluxes into the esophagus, “heartburn” </li></ul><ul><ul><li>Poorly protected so it becomes inflamed and irritated </li></ul></ul><ul><ul><li>Overweight, large meals, smoking, lying down, and hiatal hernias contribute </li></ul></ul><ul><li>GERD </li></ul><ul><ul><li>Chronic reflux esophagitis can lead to scar tissue and narrowing of lumen </li></ul></ul><ul><ul><li>Advanced cases may get Barrett esophagus where stratified squamous becomes columnar secretory epithelium and increases the risk of developing cancer </li></ul></ul><ul><ul><li>May also lead to ulcers or cancerous growths </li></ul></ul><ul><ul><li>Treat with medications to limit or neutralize stomach acid </li></ul></ul>Reflux Esophagitis and Gastroesophageal Reflux Disease (GERD) 26-
  37. 37. <ul><li>Stratified squamous in esophagus changes to simple columnar in stomach and stays simple columnar until the end of the GI tract where it becomes stratified squamous again. </li></ul><ul><li>Three muscular layers produce mixing waves </li></ul><ul><li>Rugae: deep folds in mucosa and submucosa </li></ul><ul><li>Openings in mucosal folds are gastric pits </li></ul>Stomach 26-
  38. 38. <ul><li>Storage: 2-6 hours </li></ul><ul><li>Mixing and propulsion: break down bolus into chyme </li></ul><ul><li>Protein digestion begins with pepsin </li></ul><ul><li>HCl kills microbes, pH <2, denatures proteins, and important in conversion of inactive pepsinogen into active pepsin </li></ul><ul><li>Little absorption: alcohol and aspirin (they damage stomach) </li></ul>Stomach Functions 26-
  39. 39.
  40. 40.
  41. 41.
  42. 42.
  43. 43.
  44. 44. <ul><li>Lack of vitamin B 12 leads to pernicious anemia. </li></ul>Gastrectomy 26-
  45. 45. <ul><li>Mucus (bile can produce gastritis) </li></ul><ul><li>Tight junctions </li></ul><ul><li>Rapid turnover (every three days) </li></ul><ul><li>Pepsinogen is inactive until activated by HCl </li></ul>Stomach Protected by 26-
  46. 46. Peptic Ulcers <ul><li>Chronic, solitary erosion of the lining of the stomach (gastric ulcer) or small intestine (duodenal ulcer) </li></ul><ul><li>Symptoms: gnawing, burning pain that may be worse after a meal; nausea; vomiting; and extreme belching </li></ul><ul><li>Irritation of the gastric mucosa (gastritis) in many cases (NSAIDS), but most cases related to Helicobacter pylori (present in over 70% of gastric ulcers and over 90% of duodenal ulcers) that break down the mucus and WBCs that destroy mucous neck cells </li></ul><ul><li>Treatment: antibiotics and reducing and/or neutralizing the stomach acid </li></ul>26-
  47. 47. Pyloric Sphincter <ul><li>Acts as a “gatekeeper” allowing only small amounts of chyme to enter duodenum at a time </li></ul><ul><li>The chyme contains partially digested carbohydrates, proteins, and lipids. </li></ul>26-
  48. 48. Small Intestine <ul><li>Finishes the chemical digestion process and is responsible for absorbing most of the nutrients and most of the water. </li></ul><ul><li>Chemical and mechanical digestion depend also on accessory structures: pancreas, liver, and gall bladder. </li></ul><ul><li>Ingested nutrients spend at least 12 hours in the small intestine as chemical digestion and absorption are completed. </li></ul><ul><li>Coiled, thin-walled tube about 6 meters (20 feet in dead and 10 feet in living) in length. </li></ul><ul><li>Extends from the pylorus of the stomach to the ileocecal valve between the ileum and the cecum of the large intestine, and thus occupies a significant portion of the abdominal cavity. </li></ul>26-
  49. 49. Small Intestine <ul><li>The duodenum is retroperitoneal , about 25 centimeters (10 inches) long and originates at the pyloric sphincter . </li></ul><ul><li>The jejunum is about 2.5 meters (7.5 feet) </li></ul><ul><ul><li>primary region for chemical digestion and nutrient absorption </li></ul></ul><ul><li>The ileum is about 3.6 meters (10.8 feet) </li></ul><ul><ul><li>terminates at the ileocecal valve , a sphincter that controls the entry of materials into the large intestine. </li></ul></ul><ul><li>Two layers to the muscularis </li></ul><ul><li>Serosa surrounds except for major part of the duodenum. </li></ul>26-
  50. 50.
  51. 51. Small Intestine <ul><li>Almost all the digestion and absorption occur in the small intestine! </li></ul><ul><ul><li>90% of absorption in SI </li></ul></ul><ul><ul><li>10% of absorption in stomach and LI </li></ul></ul><ul><li>Large surface area (600x more than if just a tube) </li></ul><ul><ul><li>10 feet long </li></ul></ul><ul><ul><li>Plicae circulares (circular folds about 10 mm high) spiral through </li></ul></ul><ul><ul><li>Villi (0.5 - 1 mm high) </li></ul></ul><ul><ul><li>Microvilli (brush border) </li></ul></ul>26-
  52. 52. Small Intestine <ul><li>Mucosal Cavities lined with glandular epithelium </li></ul><ul><ul><li>Intestinal glands (crypts of Lieberkuhn) produce intestinal juice (1-2 liters/day) </li></ul></ul><ul><ul><li>Paneth cells produce lysozyme and also do phagocytosis </li></ul></ul><ul><ul><li>Goblet cells produce mucus </li></ul></ul><ul><li>Most of the digestion by the SI itself is by brush border enzymes on the surface or in the lumen. Help digest proteins, carbohydrates, and nucleotides. </li></ul><ul><li>Submucosa of duodenum has duodenal glands (Brunner’s glands) that produce an alkaline mucus </li></ul><ul><li>A lot of MALT in the lamina propria: many solitary lymphatic nodules and Peyer’s patches in ileum </li></ul>26-
  53. 53.
  54. 54.
  55. 55. Absorption in SI <ul><li>Active transport mainly into villi and then diffusion into capillaries then nutrients mainly go to the liver </li></ul><ul><li>Lipids diffuse into capillaries and lacteals which lead to cisterna chyli, etc. </li></ul><ul><ul><li>Fat soluble vitamins, ADEK, enter through lipids </li></ul></ul><ul><li>Undigestibles, some water and a lot of bacteria go through the ileocecal valve to the cecum of the large intestine. </li></ul>26-
  56. 56. Large Intestine <ul><li>About 1.5 meters (5 feet) long and 6.5 centimeters (2.5 inches) wide. </li></ul><ul><li>Absorbs most of the water and electrolytes from the remaining digested material. </li></ul><ul><li>Absorbs a very small percentage of nutrients still remaining in the digested material. </li></ul><ul><li>Vitamin manufacture here by bacteria </li></ul><ul><li>Watery material that first enters the large intestine soon solidifies and becomes feces . </li></ul><ul><li>Stores this fecal material 3-10 hours until the body is ready to defecate. </li></ul><ul><li>Composed of four segments: </li></ul><ul><ul><li>the cecum, colon, rectum, anal canal </li></ul></ul><ul><li>Attached to the posterior abdominal wall by the mesocolon. </li></ul>26-
  57. 57.
  58. 58. Movements in the Large Intestine <ul><li>Peristalsis - slower than before </li></ul><ul><li>Haustral churning: haustra fill and then contract </li></ul><ul><li>Mass peristalsis: strong movements 3-4x/day during or after meal </li></ul>26-
  59. 59.
  60. 60. <ul><li>No circular folds and no villi </li></ul><ul><li>Intestinal glands </li></ul><ul><ul><li>Microvilli present in absorptive cells </li></ul></ul><ul><ul><li>Goblet cells secrete mucus </li></ul></ul>Histology of LI 26-
  61. 61.
  62. 62.
  63. 63. Digestion in LI <ul><li>Chemical digestion is bacterial by E . coli not enzymatic </li></ul><ul><li>Typically, feces has about 25% bacteria. Bacteria in the SI and LI are in the lumen! </li></ul><ul><li>Bacteria ferment carbohydrates and produce gases (flatus). Bacteria synthesize B vitamins and vitamin K. Vitamins are absorbed here. </li></ul><ul><li>Amino acids are broken down to small substances that have an odor. Some of these go to the liver for detoxification and leave through the urine </li></ul><ul><li>Bilirubin may be converted to urobilinogen and leave through the urine or to stercobilin and produce the brown color of feces </li></ul>26-
  64. 64. Defecation <ul><li>Mass peristalsis from the sigmoid colon initiates defecation reflex (parasympathetic) </li></ul>26-
  65. 65. Appendicitis <ul><li>Perforation allows bacteria to enter the body and cause peritonitis, massive infection </li></ul><ul><ul><li>Pain first over umbilicus, then in right lower quadrant </li></ul></ul><ul><ul><li>Shock </li></ul></ul><ul><ul><li>Renal failure </li></ul></ul><ul><ul><li>Respiratory insufficiency </li></ul></ul><ul><ul><li>Liver failure </li></ul></ul>26-
  66. 66. <ul><li>Second most common type of cancer in US </li></ul><ul><ul><li>especially found in sigmoid colon, and distal descending colon </li></ul></ul><ul><li>Most arise from polyps (most polyps benign) </li></ul><ul><li>Risk factors: low fiber diet, family history, ulcerative colitis, and increased age. </li></ul><ul><li>Symptoms: often none at first, bleeding, change in bowel habits. Later, pain, fatigue, weight loss, and anemia. </li></ul><ul><li>Treatment: surgery, chemo, radiation. </li></ul><ul><li>Screening at 50 or earlier if at risk: </li></ul><ul><ul><li>Fecal occult blood test yearly </li></ul></ul><ul><ul><li>Sigmoidoscopy every 5 years </li></ul></ul><ul><ul><li>Colonoscopy every 10 years </li></ul></ul>Colorectal Cancer 26-
  67. 67. Accessory Digestive Organs <ul><li>The liver, about 3# (heaviest gland) </li></ul><ul><ul><li>composed of four incompletely separated lobes </li></ul></ul><ul><ul><ul><li>Right lobe </li></ul></ul></ul><ul><ul><ul><li>Left lobe </li></ul></ul></ul><ul><ul><ul><li>Caudate lobe </li></ul></ul></ul><ul><ul><ul><li>Quadrate lobe </li></ul></ul></ul><ul><ul><li>supported by two ligaments </li></ul></ul><ul><ul><ul><li>Falciform ligament (attaches to peritoneum) </li></ul></ul></ul><ul><ul><ul><li>Round ligament (ligamentum teres) from umb. vein </li></ul></ul></ul>26-
  68. 68. Functions of The Liver <ul><li>Produces bile, an emulsifier, not an enzyme. </li></ul><ul><ul><li>a greenish fluid that breaks down fats into small droplets to assist in their chemical digestion </li></ul></ul><ul><li>Detoxifies drugs, metabolites, and poisons. </li></ul><ul><li>Stores excess nutrients and vitamins and release them when they are needed (a key metabolic organ). </li></ul><ul><li>Synthesizes blood plasma proteins such as albumins, globulins, and proteins required for blood clotting. </li></ul><ul><li>Phagocytizes debris in the blood. </li></ul><ul><li>Helps break down and recycle components of aged erythrocytes and damaged or worn-out formed elements. </li></ul><ul><li>Helps activate vitamin D along with the skin and kidneys to its active form. </li></ul>26-
  69. 69.
  70. 70.
  71. 71.
  72. 72.
  73. 73.
  74. 74. <ul><li>Yellowish color to skin and mucous membranes </li></ul><ul><li>Three major types </li></ul><ul><ul><li>Increase production of bilirubin </li></ul></ul><ul><ul><li>Liver disease </li></ul></ul><ul><ul><li>Blockage from stones or cancer in the area </li></ul></ul><ul><ul><li>Also neonatal (physiological) jaundice that disappears as the liver matures </li></ul></ul>Jaundice 26-
  75. 75. Cirrhosis of the Liver <ul><li>Destruction of hepatocytes and their replacement with fibrous scar tissue which compresses the blood vessels and bile ducts leading to hepatic portal hypertension and obstruction to the flow of bile </li></ul><ul><li>Caused by chronic injury to the hepatocytes from chronic alcoholism, liver disease, or certain drugs or toxins. </li></ul><ul><ul><li>Hepatitis A: virus enters through fecal/oral route </li></ul></ul><ul><ul><li>Hepatitis B: serum hepatitis (can also cause cancer) </li></ul></ul><ul><ul><li>Hepatitis C: blood transfusions, IV drug use, sex </li></ul></ul><ul><li>Early stages may be asymptomatic. Later, fatigue, weight loss, and nausea, and maybe pain. Liver may be small and hard. Biopsy to confirm diagnosis. </li></ul><ul><li>Irreversible but may halt progression,. </li></ul>26-
  76. 76. Cirrhosis of the Liver <ul><li>Complications if advanced: </li></ul><ul><ul><li>Jaundice (yellowing of skin and sclerae from bilirubin) </li></ul></ul><ul><ul><li>Edema and ascites </li></ul></ul><ul><ul><li>Intense itching </li></ul></ul><ul><ul><li>Accumulation of toxins in blood and brain </li></ul></ul><ul><ul><li>Portal hypertension can lead to dilated veins in the inferior esophagus (esophageal varices) </li></ul></ul><ul><li>End-stage liver cirrhosis requires a liver transplant </li></ul>26-
  77. 77. Accessory Digestive Organs <ul><li>Gallbladder (about 3-4 inches long) </li></ul><ul><ul><li>concentrates bile produced by the liver and stores this concentrate until it is needed for digestion </li></ul></ul><ul><ul><li>cystic duct connects the gallbladder to the common bile duct </li></ul></ul><ul><ul><li>can hold approximately 50 milliliters of concentrated bile </li></ul></ul><ul><ul><li>simple columnar with no submucosa </li></ul></ul><ul><ul><li>has rugae </li></ul></ul><ul><ul><li>hormones cause its smooth muscle to contract and release bile into the cystic duct. </li></ul></ul>26-
  78. 78. Gallstones <ul><li>Concentration of materials: cholesterol or calcium and bile salts </li></ul><ul><li>Risk factors: obesity, age, female sex hormones, Caucasian, lack of physical activity </li></ul><ul><li>Usually asymptomatic until they become lodged in the cystic duct, then severe pain in the r. hypochondriac region or r. shoulder, nausea and vomiting, indigestion and bloating may occur. </li></ul><ul><li>Treatment: removal of gall bladder (cholecystectomy) </li></ul>26-
  79. 79. Accessory Digestive Organs <ul><li>The biliary apparatus. </li></ul><ul><ul><li>network of thin ducts that carry bile from the liver and gallbladder to the duodenum </li></ul></ul>26-
  80. 80.
  81. 81. Accessory Digestive Organs <ul><li>Pancreas </li></ul><ul><ul><li>mixed gland: both endocrine and exocrine functions </li></ul></ul><ul><li>Secretes digestive enzymes, collectively called pancreatic juice (1 1/2 liters/day), into the duodenum. </li></ul><ul><ul><li>99% of the pancreas are are exocrine acinar cells </li></ul></ul><ul><ul><li>Digests carbohydrates, fats, proteins, and nucleic acids </li></ul></ul><ul><ul><li>Bicarbonate ions buffer HCl from stomach </li></ul></ul><ul><ul><li>Under hormonal and neural control </li></ul></ul><ul><li>Retroperitoneal </li></ul>26-
  82. 82.
  83. 83. Intestinal Disorders 26-
  84. 84. Celiac Disease <ul><li>Autoimmune disease of SI mucosa where villi are attacked. </li></ul><ul><li>Gluten sensitive </li></ul><ul><ul><li>Gluten found in wheat, rye, and barley </li></ul></ul><ul><li>Symptoms like many other GI problems </li></ul><ul><li>Must watch diet and avoid gluten </li></ul>26-
  85. 85. Inflammatory Bowel Disease <ul><li>IBD: selective regions of the bowel become inflamed. Two autoimmune disorders. </li></ul><ul><li>Crohn disease </li></ul><ul><ul><li>Young adults </li></ul></ul><ul><ul><li>Periodic intense abdominal cramping and diarrhea </li></ul></ul><ul><ul><li>Usually in the distal ileum. Entire thickness of the wall is involved. </li></ul></ul><ul><ul><li>Linear ulcerations of the mucosa are frequent and in some scarring may lead to bowel obstruction. Some may develop selective malabsorption of some vitamins. </li></ul></ul>26-
  86. 86. Inflammatory Bowel Disease <ul><li>Ulcerative colitis </li></ul><ul><ul><li>Similar age distribution and symptoms, but only colon involved </li></ul></ul><ul><ul><li>Rectum and descending colon show first signs of inflammation and most severe effects usually </li></ul></ul><ul><ul><li>Inflammation confined to mucosa </li></ul></ul><ul><ul><li>If patient has UC for more than 10 years, then chances for colon cancer are increased 20-30x. Need careful monitoring. </li></ul></ul><ul><li>Treatment for IBD </li></ul><ul><ul><li>Complex and multidisciplinary approach usually. </li></ul></ul><ul><ul><li>Anti-inflammatory drugs, stress reduction, and maybe nutritional supplementation. Surgery may be necessary. </li></ul></ul>26-
  87. 87. <ul><li>More common but not IBD, one in five have it. Cause and cure not known. Control by decreasing stress, changing one’s diet, and using certain medications. </li></ul>Irritable Bowel Syndrome 26-
  88. 88. Other GI Problems <ul><li>Dental caries and periodontal disease </li></ul><ul><li>Eating disorders </li></ul><ul><li>Diverticulitis </li></ul><ul><li>Obstruction </li></ul><ul><li>Diarrhea </li></ul><ul><li>Constipation </li></ul>26-

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