Ch14 Digestive System Overview
- 1. Chapter 14 The Digestive System and Body Metabolism
- 2. The Digestive System and Body Metabolism Slide 14.1 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Digestion Breakdown of ingested food Absorption of nutrients into the blood Metabolism Production of cellular energy (ATP) Constructive and degradative cellular activities
- 3. Organs of the Digestive System Slide 14.2a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Two main groups Alimentary canal – continuous coiled hollow tube Accessory digestive organs
- 4. Organs of the Digestive System – know diagram for test Slide 14.2b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 14.1
- 5. Know pathway - Organs of the Alimentary Canal Slide 14.3 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Mouth Pharynx Esophagus Stomach Small intestine Large intestine Anus
- 6. Mouth (Oral Cavity) Anatomy p434 Slide 14.4 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Lips (labia) – protect the anterior opening Cheeks – form the lateral walls Hard palate – forms the anterior roof Soft palate – forms the posterior roof Uvula – fleshy projection of the soft palate Figure 14.2a
- 7. Mouth (Oral Cavity) Anatomy Slide 14.5 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Vestibule – space between lips externally and teeth and gums internally Oral cavity – area contained by the teeth Tongue – attached at hyoid and styloid processes of the skull, and by the lingual frenulum Figure 14.2a
- 8. Mouth (Oral Cavity) Anatomy Slide 14.6 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Tonsils Palatine tonsils Lingual tonsil Figure 14.2a
- 9. Processes of the Mouth Slide 14.7 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Mastication (chewing) of food Mixing masticated food with saliva Initiation of swallowing by the tongue Allowing for the sense of taste
- 10. Pharynx Anatomy Slide 14.8 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Nasopharynx – not part of the digestive system Oropharynx – posterior to oral cavity Laryngopharynx – below the oropharynx and connected to the esophagus Figure 14.2a
- 11. Pharynx Function Slide 14.9 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Serves as a passageway for air and food Food is propelled to the esophagus by two muscle layers Longitudinal inner layer Circular outer layer Food movement is by alternating contractions of the muscle layers (peristalsis)
- 12. Esophagus Slide 14.10 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Runs from pharynx to stomach through the diaphragm (approx 10 inches long) Conducts food by peristalsis (slow rhythmic squeezing) Passageway for food only (respiratory system branches off after the pharynx)
- 13. Layers of Alimentary Canal Organs p. 436 Slide 14.11a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Mucosa Innermost layer Moist membrane Surface epithelium Small amount of connective tissue (lamina propria) Small smooth muscle layer
- 14. Layers of Alimentary Canal Organs Slide 14.11b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Submucosa Just beneath the mucosa Soft connective tissue with blood vessels, nerve endings, and lymphatics
- 15. Layers of Alimentary Canal Organs Slide 14.12 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Muscularis externa – smooth muscle Inner circular layer Outer longitudinal layer Serosa Outermost layer – visceral peritoneum Layer of serous fluid-producing cells
- 16. Stomach Anatomy p. 437 Located on the left side of the abdominal cavity (approx 10 inches long, when full can hold 1 gallon of food) Food enters at the cardioesophageal sphincter Regions of the stomach Cardiac region – near the heart Fundus Body Phylorus – funnel-shaped terminal end Food empties into the small intestine at the pyloric sphincter
- 17. Stomach Anatomy Slide 14.16a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Rugae – internal folds of the mucosa Disappear when full. When empty collapses again. External regions Lesser curvature Greater curvature
- 18. Stomach Functions Slide 14.18 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Acts as a storage tank for food Site of food breakdown Chemical breakdown of protein begins Delivers chyme (processed food) to the small intestine
- 19. Specialized Mucosa of the Stomach p. 437 b,c Slide 14.19 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Simple columnar epithelium Mucous neck cells – produce a sticky alkaline mucus Gastric glands – secrete gastric juice Chief cells – produce protein-digesting enzymes (pepsinogens) Parietal cells – produce hydrochloric acid Endocrine cells – produce gastrin
- 20. Small Intestine p. 440 Slide 14.21 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The body’s major digestive organ (approx 6-13 ft) Site of nutrient absorption into the blood Muscular tube extending form the pyloric sphincter (“gatekeeper”) to the ileocecal valve Suspended from the posterior abdominal wall by the mesentery
- 21. Subdivisions of the Small Intestine Slide 14.22 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Duodenum (approx 10 inches) Attached to the stomach Curves around the head of the pancreas Jejunum (approx 8 ft) Attaches anteriorly to the duodenum Ileum (approx 12 ft) Extends from jejunum to large intestine
- 22. Chemical Digestion in the Small Intestine Slide 14.23a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Source of enzymes that are mixed with chyme Intestinal cells Pancreas Bile enters from the gall bladder
- 23. Chemical Digestion in the Small Intestine Slide 14.23b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 14.6
- 24. Villi of the Small Intestine p 440 Slide 14.24 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Fingerlike structures formed by the mucosa Give the small intestine more surface area Figure 14.7a
- 25. Microvilli of the Small Intestine Slide 14.25 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Small projections of the plasma membrane Found on absorptive cells Figure 14.7c
- 26. Folds of the Small Intestine Slide 14.27 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Called circular folds or plicae circulares Deep folds of the mucosa and submucosa (structures decrease toward end of Sm Int.) Do not disappear when filled with food 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)
- 27. Large Intestine p. 441 Slide 14.28 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Larger in diameter, but shorter than the small intestine (5ft) Frames the internal abdomen
- 28. Large Intestine Slide 14.28 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 14.8
- 29. Functions of the Large Intestine Slide 14.29 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Absorption of water Eliminates indigestible food from the body as feces Does not participate in digestion of food Goblet cells produce mucus to act as a lubricant
- 30. Structures of the Large Intestine Slide 14.30a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Cecum – saclike first part of the large intestine Appendix Accumulation of lymphatic tissue that sometimes becomes inflamed (b/c of accumulated bacteria - appendicitis) Hangs from the cecum
- 31. Structures of the Large Intestine Slide 14.30b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Colon Ascending Transverse Descending S-shaped sigmoidal Rectum Anus – external body opening
- 32. Large Intestine additional Information Slide 14.61 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings No digestive enzymes are produced Resident bacteria digest remaining nutrients Produce some vitamin K and B Release gases Water and vitamins K and B are absorbed Remaining materials are eliminated
- 33. Accessory Digestive Organs Slide 14.32 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Salivary glands Teeth Pancreas Liver Gall bladder Spleen
- 34. Salivary Glands Slide 14.33 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Saliva-producing glands Parotid glands – located anterior to ears Submandibular glands Sublingual glands
- 35. Saliva Slide 14.34 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Mixture of mucus and serous fluids Helps to form a food bolus Contains salivary amylase to begin starch digestion Dissolves chemicals so they can be tasted
- 36. Teeth Slide 14.35a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The role is to masticate (chew) food Humans have two sets of teeth Deciduous (baby or milk) teeth 20 teeth are fully formed by age two
- 37. Pancreas Slide 14.38 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Produces a wide spectrum of digestive enzymes that break down all categories of food Enzymes are secreted into the duodenum Alkaline fluid introduced with enzymes neutralizes acidic chyme Endocrine products of pancreas Insulin Glucagons
- 38. Liver Slide 14.39 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Largest gland in the body Located on the right side of the body under the diaphragm Consists of four lobes suspended from the diaphragm and abdominal wall by the falciform ligament Connected to the gall bladder via the common hepatic duct
- 39. Bile Slide 14.40 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Produced by cells in the liver Composition Bile salts – emulsifies fats (lipids)
- 40. Gall Bladder Slide 14.41 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Sac found in hollow fossa of liver Stores bile from the liver by way of the cystic duct Bile is introduced into the duodenum in the presence of fatty food Gallstones can cause blockages
- 41. Spleen Slide 14.41 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Both immune and “digestive” functions Destroys worn out RBC and returns some of the breakdown products to the liver to be metabolized
- 42. Nutrition Slide 14.63 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Nutrient – substance used by the body for growth, maintenance, and repair Categories of nutrients Carbohydrates Lipids Proteins Vitamins Mineral Water
- 43. Dietary Sources of Major Nutrients Slide 14.64 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Carbohydrates Most are derived from plants Exceptions: lactose from milk and small amounts of glycogens from meats Lipids Saturated fats from animal products Unsaturated fats from nuts, seeds, and vegetable oils Cholesterol from egg yolk, meats, and milk products
- 44. Dietary Sources of Major Nutrients Slide 14.65 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Proteins Complete proteins – contain all essential amino acids Most are from animal products Legumes and beans also have proteins, but are incomplete Vitamins Most vitamins are used as cofactors and act with enzymes Found in all major food groups
- 45. Dietary Sources of Major Nutrients Slide 14.66 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Minerals Play many roles in the body Most mineral-rich foods are vegetables, legumes, milk, and some meats