1. Human Anatomy & Physiology Chapter 5 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  Passage of nutrients into the blood  Metabolism  Production of cellular energy (ATP)

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 Slide 14.2b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 14.1

5. 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 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- used for swallowing and taste 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  Saliva begins digestion of carbohydrates  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  Food movement is by alternating contractions of the muscle layers (peristalsis)  Serves as a passageway for air and food  Food is propelled to the esophagus by two muscle layers  It’s like pushing a pea down a straw

12. Esophagus Slide 14.10 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Connects the mouth to the stomach  Runs from pharynx to stomach through the diaphragm  Conducts food by peristalsis (slow rhythmic squeezing)  Passageway for food only

13. Layers of Alimentary Canal Organs 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. Layers of Alimentary Canal Organs Slide 14.13 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 14.3

17. Stomach Anatomy Slide 14.15a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Located on the left side of the abdominal cavity  About the size of a fist  Food enters at the cardioesophageal sphincter  Connects the Esophagus to the Stomach

18. Stomach Anatomy Slide 14.15b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Regions of the stomach  Cardiac region – near the heart  Fundus- top “bubble” area  Body- majority/mass of the organ  Pylorus – funnel-shaped terminal end  Food empties into the small intestine at the pyloric sphincter

20. Stomach Anatomy Slide 14.16a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Rugae – internal folds of the mucosa  External regions  Lesser curvature  Greater curvature

21. Stomach Anatomy Slide 14.16b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Layers of connenctive tissue attached to the stomach  Lesser omentum – attaches the liver to the lesser curvature  Greater omentum – attaches the greater curvature to the posterior body wall  Contains fat to insulate, cushion, and protect abdominal organs

23. Stomach Anatomy Slide 14.17 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 14.4a

24. Stomach Functions Slide 14.18 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Acts as a storage tank for food  Chemical breakdown of protein begins  Mucus protects the cells from chemical digestion  Delivers chyme (processed food) to the small intestine

25. Specialized Mucosa of the Stomach 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

26. Structure of the Stomach Mucosa Slide 14.20b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 14.4b, c

27. Small Intestine Slide 14.21 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Functions include:  Neutralizes acids from stomach  Uses enzymes to break down carbohydrates, fats and proteins  Site of nutrient absorption into the blood

29. Subdivisions of the Small Intestine “Dogs Just Itch! Slide 14.22 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Duodenum  Attached to the stomach  Curves around the head of the pancreas  Jejunum  Attaches anteriorly to the duodenum  Ileum  Extends from jejunum to large intestine

31. Digestion in the Duodenum Slide 14.57a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Enzymes do the following:  Break double sugars into simple sugars  Complete some protein digestion  Pancreatic enzymes play the major digestive function  Help complete digestion of starch (pancreatic amylase)  Carry out about half of all protein digestion

32. Digestion in the Duodenum Slide 14.57b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Pancreatic enzymes play the major digestive function (continued)  Responsible for fat digestion (lipase)  Digest nucleic acids (nucleases)

33. Chemical Digestion in the Small Intestine Slide 14.23b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 14.6

34. Digestion in the Jejunum/Ileum  Majority of the nutrients are absorbed in the lining of the small intestine where they are transported to the liver for processing  Specialized structures, called villi aid in the absorption by increasing surface area

35. Villi of the Small Intestine 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

36. Microvilli of the Small Intestine Slide 14.25 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Small projections of the plasma membrane of each cell in the villi  Found on absorptive cells Figure 14.7c

38. Structures Involved in Absorption of Nutrients Slide 14.26 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Absorptive cells  Blood capillaries Figure 14.7b

39. Absorption in the Small Intestine Slide 14.59 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Some water is absorbed along the length of the small intestine  End products of digestion  Most substances are absorbed by active transport through cell membranes  Lipids are absorbed by diffusion

40. Propulsion in the Small Intestine Slide 14.60 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Peristalsis is the major means of moving food  Segmental movements  Mix chyme with digestive juices  Aid in propelling food

41. Large Intestine Slide 14.28 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Larger in diameter, but shorter than the small intestine  Frames the internal abdomen

42. Large Intestine Slide 14.28 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 14.8

43. 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

44. 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 (appendicitis)  Hangs from the cecum

45. Structures of the Large Intestine Slide 14.30b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Colon  Ascending- upward region  Transverse-across region  Descending- downward region  S-shaped sigmoidal- near the end  Rectum- stores feces for removal  Anus – external body opening

46. 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

47. Food Breakdown and Absorption in the Large Intestine 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 via feces

48. Propulsion in the Large Intestine Slide 14.62 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Sluggish peristalsis causes defecation  Mass movements  Slow, powerful movements  Occur three to four times per day  Presence of feces in the rectum causes a defecation reflex  Internal anal sphincter is relaxed  Defecation occurs with relaxation of the voluntary (external) anal sphincter

49. What are feces made up of? Slide 14.32 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings 1.Bilirubin from dead blood cells (which gives it a brown hue) 2.75% water 3.1/3 of the remaining is dead bacteria that help digest food 4.Remaining portion is indigestible food (fiber,) fats, proteins, cholesterol, phosphate salts, and mucus from the intestines

50. Fecal matter Slide 14.62 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The seven types of stool are: 1.Separate hard lumps, like nuts (hard to pass) 2.Sausage-shaped but lumpy 3.Like a sausage but with cracks on its surface 4.Like a sausage or snake, smooth and soft 5.Soft blobs with clear cut edges (passed easily) 6.Fluffy pieces with ragged edges, a mushy stool 7.Watery stool, entirely liquid.

51. What do the different colors mean? Slide 14.32 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Color variation is normal; however certain persistent changes in stool color are characteristic for specific conditions:  black, foul-smelling stool: intestinal bleeding (typically from the stomach and upper small intestine) due to ulcers, tumors; ingestion of iron or bismuth  maroon stool: intestinal bleeding (from the middle intestine or proximal colon) due to ulcers, tumors, Crohn's disease, ulcerative colitis  clay-colored stool: lack of bile due to blockage of the main bile duct  pale yellow, greasy, foul-smelling stool: malabsorption of fat due to pancreatic insufficiency, as seen with pancreatitis, pancreatic cancer, cystic fibrosis, celiac disease

52. Accessory Digestive Organs Slide 14.32 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Salivary glands  Teeth  Pancreas  Liver  Gall bladder

53. 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

54. 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

55. 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

56. Teeth Slide 14.35b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Permanent teeth  Replace deciduous teeth beginning between the ages of 6 to 12  A full set is 32 teeth, but some people do not have wisdom teeth

57. Classification of Teeth Slide 14.36a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Incisors  Canines  Premolars  Molars

58. Classification of Teeth Slide 14.36b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 14.9

59. Regions of a Tooth Slide 14.37a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Crown – exposed part  Outer enamel  Dentin  Pulp cavity  Neck  Region in contact with the gum  Connects crown to root Figure 14.10

60. Regions of a Tooth Slide 14.37b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Root  Periodontal membrane attached to the bone  Root canal carrying blood vessels and nerves Figure 14.10

61. 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

62. 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

63. Bile Slide 14.40 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Produced by cells in the liver  Composition  Bile salts  Bile pigment (mostly bilirubin from the breakdown of hemoglobin)  Cholesterol  Phospholipids  Electrolytes

64. Role of the Liver in Metabolism Slide 14.77 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Several roles in digestion  Detoxifies drugs and alcohol  Degrades hormones  Produce cholesterol, blood proteins (albumin and clotting proteins)  Plays a central role in metabolism

65. 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

66. Processes of the Digestive System Slide 14.42a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Ingestion – getting food into the mouth  Propulsion – moving foods from one region of the digestive system to another

67. Processes of the Digestive System Slide 14.42b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Peristalsis – alternating waves of contraction  Segmentation – moving materials back and forth to aid in mixing Figure 14.12

68. Processes of the Digestive System Slide 14.43 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Mechanical digestion  Mixing of food in the mouth by the tongue  Churning of food in the stomach  Segmentation in the small intestine

69. Processes of the Digestive System Slide 14.44 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Chemical Digestion  Enzymes break down food molecules into their building blocks  Each major food group uses different enzymes  Carbohydrates are broken to simple sugars  Proteins are broken to amino acids  Fats are broken to fatty acids and alcohols

70. Processes of the Digestive System Slide 14.45 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Absorption  End products of digestion are absorbed in the blood or lymph  Food must enter mucosal cells and then into blood or lymph capillaries  Defecation  Elimination of indigestible substances as feces

71. Control of Digestive Activity Slide 14.47a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Mostly controlled by reflexes via the parasympathetic division  Chemical and mechanical receptors are located in organ walls that trigger reflexes

72. Body Energy Balance Slide 14.83 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Energy intake = total energy output (heat + work + energy storage)  Energy intake is liberated during food oxidation  Energy output  Heat is usually about 60%  Storage energy is in the form of fat or glycogen

73. Cirrhosis of the liver Cirrhosis is a condition in which the liver slowly deteriorates and malfunctions due to chronic injury. Scar tissue replaces healthy liver tissue, partially blocking the flow of blood through the liver Caused by alcohol and drug abuse, Hepatitis C, B, D Obesity Cystic fibrosis and other inherited diseases Infection

74. Stenosing web of the esophagus Esophageal stenosis is a condition where there is a narrowing of the esophagus. With an esophageal stenosis, an abnormal change or injury may have caused inflammation (swelling) and damage to the esophagus. When the damaged areas heal, scar tissue forms and make the affected area of the esophagus hard. This narrows the esophagus and causes problems for foods and liquids to pass through. Causes: Acid reflux (most common,) cancer, allergies and trauma

75. Gall Stones Small, pebble-like objects in the gall bladder made of bile salts and cholesterol. The cause of gallstones varies. There are two main types of gallstones: Stones made of cholesterol, which are by far the most common type. Cholesterol gallstones have nothing to do with cholesterol levels in the blood. Stones made of bilirubin, which can occur when red blood cells are being destroyed. This leads to too much bilirubin in the bile. These stones are called pigment stones.

76. Inflammatory Bowel Disease Inflammatory bowel disease (which is not the same thing as irritable bowel syndrome, or IBS) refers to two chronic diseases that cause inflammation of the intestines: ulcerative colitis and Crohn's disease. Current evidence suggests that a genetic defect affects how the immune system works and how inflammation is triggered in response to an offending agent, like bacteria, a virus, or a protein in food.

77. Duodenal ulcer A duodenal ulcer is a type of peptic ulcer that occurs in the duodenum, the beginning of the small intestine. Peptic ulcers are eroded areas in the lining of stomach and duodenum, which result in abdominal pain, possible bleeding, and other gastrointestinal symptoms. The most common cause of duodenal ulcer is a stomach infection associated with the Helicobacter pylori (H pylori) bacteria.

78. Intussusception caused by polyp Intussusception (in-tuh-suh-SEP-shun) is a serious disorder in which part of the intestine — either the small intestine or colon — slides into another part of the intestine. This "telescoping" often blocks the intestine, preventing food or fluid from passing through. Intussusception also cuts off the blood supply to the part of the intestine that's affected. Intussusception is the most common cause of intestinal obstruction in children but it is rare in adults. Most cases of adult intussusception are the result of an underlying medical condition. In contrast, most cases of intussusception in children have no demonstrable cause.

79. Stomach Ulcers Over 25 million Americans will have a peptic ulcer once in their lifetime Peptic ulcer is an area of damage to the inner lining of the stomach, Peptic ulcers were formerly thought to be caused by stress, coffee consumption, or spicy foods. 60% of peptic ulcers are caused by a bacterial infection Another 20% are caused by nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin and ibuprofen another 20% have miscellaneous causes such as cigarettes

80. Diverticulitis is small, bulging sacs or pouches of the inner lining of the intestine (diverticulosis) that become inflamed or infected. No one knows exactly what causes the sacs, or pouches of diverticulosis to form. Eating a low-fiber diet is one of the most likely causes. People who eat mostly processed food, as many Americans eat, do not get enough fiber in their diet. Processed foods include white rice, white bread, most breakfast cereals, crackers, and pretzels. ◦As a result, constipation and hard stools are more likely to occur - causing people to strain when passing stools. This increases the pressure in the colon or intestines and may cause these pouches to form. Diverticulosis is very common. It is found in more than half of Americans over age 60.