Ch14 Digestive System Overview

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Ch14 Digestive System Overview

  1. 1. Chapter 14 The Digestive System and Body Metabolism
  2. 2. <ul><li>The Digestive System and Body Metabolism </li></ul>Slide 14.1 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Digestion </li></ul><ul><ul><li>Breakdown of ingested food </li></ul></ul><ul><ul><li>Absorption of nutrients into the blood </li></ul></ul><ul><li>Metabolism </li></ul><ul><ul><li>Production of cellular energy (ATP) </li></ul></ul><ul><ul><li>Constructive and degradative cellular activities </li></ul></ul>
  3. 3. <ul><li>Organs of the Digestive System </li></ul>Slide 14.2a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Two main groups </li></ul><ul><ul><li>Alimentary canal – continuous coiled hollow tube </li></ul></ul><ul><ul><li>Accessory digestive organs </li></ul></ul>
  4. 4. <ul><li>Organs of the Digestive System – know diagram for test </li></ul>Slide 14.2b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 14.1
  5. 5. <ul><li>Know pathway - Organs of the Alimentary Canal </li></ul>Slide 14.3 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Mouth </li></ul><ul><li>Pharynx </li></ul><ul><li>Esophagus </li></ul><ul><li>Stomach </li></ul><ul><li>Small intestine </li></ul><ul><li>Large intestine </li></ul><ul><li>Anus </li></ul>
  6. 6. <ul><li>Mouth (Oral Cavity) Anatomy p434 </li></ul>Slide 14.4 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Lips (labia) – protect the anterior opening </li></ul><ul><li>Cheeks – form the lateral walls </li></ul><ul><li>Hard palate – forms the anterior roof </li></ul><ul><li>Soft palate – forms the posterior roof </li></ul><ul><li>Uvula – fleshy projection of the soft palate </li></ul>Figure 14.2a
  7. 7. <ul><li>Mouth (Oral Cavity) Anatomy </li></ul>Slide 14.5 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Vestibule – space between lips externally and teeth and gums internally </li></ul><ul><li>Oral cavity – area contained by the teeth </li></ul><ul><li>Tongue – attached at hyoid and styloid processes of the skull, and by the lingual frenulum </li></ul>Figure 14.2a
  8. 8. <ul><li>Mouth (Oral Cavity) Anatomy </li></ul>Slide 14.6 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Tonsils </li></ul><ul><ul><li>Palatine tonsils </li></ul></ul><ul><ul><li>Lingual tonsil </li></ul></ul>Figure 14.2a
  9. 9. <ul><li>Processes of the Mouth </li></ul>Slide 14.7 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Mastication (chewing) of food </li></ul><ul><li>Mixing masticated food with saliva </li></ul><ul><li>Initiation of swallowing by the tongue </li></ul><ul><li>Allowing for the sense of taste </li></ul>
  10. 10. <ul><li>Pharynx Anatomy </li></ul>Slide 14.8 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Nasopharynx – not part of the digestive system </li></ul><ul><li>Oropharynx – posterior to oral cavity </li></ul><ul><li>Laryngopharynx – below the oropharynx and connected to the esophagus </li></ul>Figure 14.2a
  11. 11. <ul><li>Pharynx Function </li></ul>Slide 14.9 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Serves as a passageway for air and food </li></ul><ul><li>Food is propelled to the esophagus by two muscle layers </li></ul><ul><ul><li>Longitudinal inner layer </li></ul></ul><ul><ul><li>Circular outer layer </li></ul></ul><ul><li>Food movement is by alternating contractions of the muscle layers (peristalsis) </li></ul>
  12. 12. <ul><li>Esophagus </li></ul>Slide 14.10 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Runs from pharynx to stomach through the diaphragm (approx 10 inches long) </li></ul><ul><li>Conducts food by peristalsis (slow rhythmic squeezing) </li></ul><ul><li>Passageway for food only (respiratory system branches off after the pharynx) </li></ul>
  13. 13. <ul><li>Layers of Alimentary Canal Organs p. 436 </li></ul>Slide 14.11a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Mucosa </li></ul><ul><ul><li>Innermost layer </li></ul></ul><ul><ul><li>Moist membrane </li></ul></ul><ul><ul><ul><li>Surface epithelium </li></ul></ul></ul><ul><ul><ul><li>Small amount of connective tissue (lamina propria) </li></ul></ul></ul><ul><ul><ul><li>Small smooth muscle layer </li></ul></ul></ul>
  14. 14. <ul><li>Layers of Alimentary Canal Organs </li></ul>Slide 14.11b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Submucosa </li></ul><ul><ul><li>Just beneath the mucosa </li></ul></ul><ul><ul><li>Soft connective tissue with blood vessels, nerve endings, and lymphatics </li></ul></ul>
  15. 15. <ul><li>Layers of Alimentary Canal Organs </li></ul>Slide 14.12 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Muscularis externa – smooth muscle </li></ul><ul><ul><li>Inner circular layer </li></ul></ul><ul><ul><li>Outer longitudinal layer </li></ul></ul><ul><li>Serosa </li></ul><ul><ul><li>Outermost layer – visceral peritoneum </li></ul></ul><ul><ul><li>Layer of serous fluid-producing cells </li></ul></ul>
  16. 16. <ul><li>Stomach Anatomy p. 437 </li></ul><ul><li>Located on the left side of the abdominal cavity (approx 10 inches long, when full can hold 1 gallon of food) </li></ul><ul><li>Food enters at the cardioesophageal sphincter </li></ul><ul><li>Regions of the stomach </li></ul><ul><ul><li>Cardiac region – near the heart </li></ul></ul><ul><ul><li>Fundus </li></ul></ul><ul><ul><li>Body </li></ul></ul><ul><ul><li>Phylorus – funnel-shaped terminal end </li></ul></ul><ul><li>Food empties into the small intestine at the pyloric sphincter </li></ul>
  17. 17. <ul><li>Stomach Anatomy </li></ul>Slide 14.16a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Rugae – internal folds of the mucosa </li></ul><ul><ul><li>Disappear when full. </li></ul></ul><ul><ul><li>When empty collapses again. </li></ul></ul><ul><li>External regions </li></ul><ul><ul><li>Lesser curvature </li></ul></ul><ul><ul><li>Greater curvature </li></ul></ul>
  18. 18. <ul><li>Stomach Functions </li></ul>Slide 14.18 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Acts as a storage tank for food </li></ul><ul><li>Site of food breakdown </li></ul><ul><li>Chemical breakdown of protein begins </li></ul><ul><li>Delivers chyme (processed food) to the small intestine </li></ul>
  19. 19. <ul><li>Specialized Mucosa of the Stomach </li></ul><ul><li>p. 437 b,c </li></ul>Slide 14.19 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Simple columnar epithelium </li></ul><ul><ul><li>Mucous neck cells – produce a sticky alkaline mucus </li></ul></ul><ul><ul><li>Gastric glands – secrete gastric juice </li></ul></ul><ul><ul><li>Chief cells – produce protein-digesting enzymes (pepsinogens) </li></ul></ul><ul><ul><li>Parietal cells – produce hydrochloric acid </li></ul></ul><ul><ul><li>Endocrine cells – produce gastrin </li></ul></ul>
  20. 20. <ul><li>Small Intestine p. 440 </li></ul>Slide 14.21 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>The body’s major digestive organ (approx 6-13 ft) </li></ul><ul><li>Site of nutrient absorption into the blood </li></ul><ul><li>Muscular tube extending form the pyloric sphincter (“gatekeeper”) to the ileocecal valve </li></ul><ul><li>Suspended from the posterior abdominal wall by the mesentery </li></ul>
  21. 21. <ul><li>Subdivisions of the Small Intestine </li></ul>Slide 14.22 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Duodenum (approx 10 inches) </li></ul><ul><ul><li>Attached to the stomach </li></ul></ul><ul><ul><li>Curves around the head of the pancreas </li></ul></ul><ul><li>Jejunum (approx 8 ft) </li></ul><ul><ul><li>Attaches anteriorly to the duodenum </li></ul></ul><ul><li>Ileum (approx 12 ft) </li></ul><ul><ul><li>Extends from jejunum to large intestine </li></ul></ul>
  22. 22. <ul><li>Chemical Digestion in the Small Intestine </li></ul>Slide 14.23a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Source of enzymes that are mixed with chyme </li></ul><ul><ul><li>Intestinal cells </li></ul></ul><ul><ul><li>Pancreas </li></ul></ul><ul><li>Bile enters from the gall bladder </li></ul>
  23. 23. <ul><li>Chemical Digestion in the Small Intestine </li></ul>Slide 14.23b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 14.6
  24. 24. <ul><li>Villi of the Small Intestine p 440 </li></ul>Slide 14.24 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Fingerlike structures formed by the mucosa </li></ul><ul><li>Give the small intestine more surface area </li></ul>Figure 14.7a
  25. 25. <ul><li>Microvilli of the Small Intestine </li></ul>Slide 14.25 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Small projections of the plasma membrane </li></ul><ul><li>Found on absorptive cells </li></ul>Figure 14.7c
  26. 26. <ul><li>Folds of the Small Intestine </li></ul>Slide 14.27 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Called circular folds or plicae circulares </li></ul><ul><li>Deep folds of the mucosa and submucosa (structures decrease toward end of Sm Int.) </li></ul><ul><li>Do not disappear when filled with food </li></ul><ul><li>The submucosa has Peyer’s patches (collections of lymphatic tissue, b/c of huge #’s of bacteria in undigested food payers patches toward end of sm. Int. - prevent bacteria in the blood stream) </li></ul>
  27. 27. <ul><li>Large Intestine p. 441 </li></ul>Slide 14.28 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Larger in diameter, but shorter than the small intestine (5ft) </li></ul><ul><li>Frames the internal abdomen </li></ul>
  28. 28. <ul><li>Large Intestine </li></ul>Slide 14.28 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 14.8
  29. 29. <ul><li>Functions of the Large Intestine </li></ul>Slide 14.29 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Absorption of water </li></ul><ul><li>Eliminates indigestible food from the body as feces </li></ul><ul><li>Does not participate in digestion of food </li></ul><ul><li>Goblet cells produce mucus to act as a lubricant </li></ul>
  30. 30. <ul><li>Structures of the Large Intestine </li></ul>Slide 14.30a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Cecum – saclike first part of the large intestine </li></ul><ul><li>Appendix </li></ul><ul><ul><li>Accumulation of lymphatic tissue that sometimes becomes inflamed (b/c of accumulated bacteria - appendicitis) </li></ul></ul><ul><ul><li>Hangs from the cecum </li></ul></ul>
  31. 31. <ul><li>Structures of the Large Intestine </li></ul>Slide 14.30b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Colon </li></ul><ul><ul><li>Ascending </li></ul></ul><ul><ul><li>Transverse </li></ul></ul><ul><ul><li>Descending </li></ul></ul><ul><ul><li>S-shaped sigmoidal </li></ul></ul><ul><li>Rectum </li></ul><ul><li>Anus – external body opening </li></ul>
  32. 32. <ul><li>Large Intestine additional Information </li></ul>Slide 14.61 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>No digestive enzymes are produced </li></ul><ul><li>Resident bacteria digest remaining nutrients </li></ul><ul><ul><li>Produce some vitamin K and B </li></ul></ul><ul><ul><li>Release gases </li></ul></ul><ul><li>Water and vitamins K and B are absorbed </li></ul><ul><li>Remaining materials are eliminated </li></ul>
  33. 33. <ul><li>Accessory Digestive Organs </li></ul>Slide 14.32 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Salivary glands </li></ul><ul><li>Teeth </li></ul><ul><li>Pancreas </li></ul><ul><li>Liver </li></ul><ul><li>Gall bladder </li></ul><ul><li>Spleen </li></ul>
  34. 34. <ul><li>Salivary Glands </li></ul>Slide 14.33 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Saliva-producing glands </li></ul><ul><ul><li>Parotid glands – located anterior to ears </li></ul></ul><ul><ul><li>Submandibular glands </li></ul></ul><ul><ul><li>Sublingual glands </li></ul></ul>
  35. 35. <ul><li>Saliva </li></ul>Slide 14.34 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Mixture of mucus and serous fluids </li></ul><ul><li>Helps to form a food bolus </li></ul><ul><li>Contains salivary amylase to begin starch digestion </li></ul><ul><li>Dissolves chemicals so they can be tasted </li></ul>
  36. 36. <ul><li>Teeth </li></ul>Slide 14.35a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>The role is to masticate (chew) food </li></ul><ul><li>Humans have two sets of teeth </li></ul><ul><ul><li>Deciduous (baby or milk) teeth </li></ul></ul><ul><ul><li>20 teeth are fully formed by age two </li></ul></ul>
  37. 37. <ul><li>Pancreas </li></ul>Slide 14.38 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Produces a wide spectrum of digestive enzymes that break down all categories of food </li></ul><ul><li>Enzymes are secreted into the duodenum </li></ul><ul><li>Alkaline fluid introduced with enzymes neutralizes acidic chyme </li></ul><ul><li>Endocrine products of pancreas </li></ul><ul><ul><li>Insulin </li></ul></ul><ul><ul><li>Glucagons </li></ul></ul>
  38. 38. <ul><li>Liver </li></ul>Slide 14.39 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Largest gland in the body </li></ul><ul><li>Located on the right side of the body under the diaphragm </li></ul><ul><li>Consists of four lobes suspended from the diaphragm and abdominal wall by the falciform ligament </li></ul><ul><li>Connected to the gall bladder via the common hepatic duct </li></ul>
  39. 39. <ul><li>Bile </li></ul>Slide 14.40 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Produced by cells in the liver </li></ul><ul><li>Composition </li></ul><ul><ul><li>Bile salts – emulsifies fats (lipids) </li></ul></ul>
  40. 40. <ul><li>Gall Bladder </li></ul>Slide 14.41 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Sac found in hollow fossa of liver </li></ul><ul><li>Stores bile from the liver by way of the cystic duct </li></ul><ul><li>Bile is introduced into the duodenum in the presence of fatty food </li></ul><ul><li>Gallstones can cause blockages </li></ul>
  41. 41. <ul><li>Spleen </li></ul>Slide 14.41 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Both immune and “digestive” functions </li></ul><ul><li>Destroys worn out RBC and returns some of the breakdown products to the liver to be metabolized </li></ul>
  42. 42. <ul><li>Nutrition </li></ul>Slide 14.63 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Nutrient – substance used by the body for growth, maintenance, and repair </li></ul><ul><li>Categories of nutrients </li></ul><ul><ul><li>Carbohydrates </li></ul></ul><ul><ul><li>Lipids </li></ul></ul><ul><ul><li>Proteins </li></ul></ul><ul><ul><li>Vitamins </li></ul></ul><ul><ul><li>Mineral </li></ul></ul><ul><ul><li>Water </li></ul></ul>
  43. 43. <ul><li>Dietary Sources of Major Nutrients </li></ul>Slide 14.64 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Carbohydrates </li></ul><ul><ul><li>Most are derived from plants </li></ul></ul><ul><ul><li>Exceptions: lactose from milk and small amounts of glycogens from meats </li></ul></ul><ul><li>Lipids </li></ul><ul><ul><li>Saturated fats from animal products </li></ul></ul><ul><ul><li>Unsaturated fats from nuts, seeds, and vegetable oils </li></ul></ul><ul><ul><li>Cholesterol from egg yolk, meats, and milk products </li></ul></ul>
  44. 44. <ul><li>Dietary Sources of Major Nutrients </li></ul>Slide 14.65 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Proteins </li></ul><ul><ul><li>Complete proteins – contain all essential amino acids </li></ul></ul><ul><ul><ul><li>Most are from animal products </li></ul></ul></ul><ul><ul><li>Legumes and beans also have proteins, but are incomplete </li></ul></ul><ul><li>Vitamins </li></ul><ul><ul><li>Most vitamins are used as cofactors and act with enzymes </li></ul></ul><ul><ul><li>Found in all major food groups </li></ul></ul>
  45. 45. <ul><li>Dietary Sources of Major Nutrients </li></ul>Slide 14.66 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings <ul><li>Minerals </li></ul><ul><ul><li>Play many roles in the body </li></ul></ul><ul><ul><li>Most mineral-rich foods are vegetables, legumes, milk, and some meats </li></ul></ul>

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