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Digestion,Digestion,
Absorption, andAbsorption, and
TransportTransport
Chapter 3Chapter 3
DigestionDigestion
• Breaking down foods into nutrients
• Prepare for absorption
• Challenges of digestion
• Tasks of the ...
Anatomy of the Digestive TractAnatomy of the Digestive Tract
• Gastrointestinal (GI) tract
• Flexible and muscular
• Path
...
The Gastrointestinal TractThe Gastrointestinal Tract
Anatomy of the Digestive TractAnatomy of the Digestive Tract
• Mouth
• Process of digestion begins
• Mastication
• Four ba...
Anatomy of the Digestive TractAnatomy of the Digestive Tract
• Esophagus
• Two sphincters
• Upper esophageal sphincter
• L...
Anatomy of the Digestive TractAnatomy of the Digestive Tract
• Small intestine
• Common bile duct
• Pancreas and gall blad...
Transverse
colon
Ascending
colon
Descending
colon
Sigmoid
colonAnus
Rectum
Appendix
Opening from
small intestine
to large ...
Transverse
colon
Ascending
colon
Descending
colon
Sigmoid
colonAnus
Rectum
Appendix
Opening from
small intestine
to large ...
Muscular Action of DigestionMuscular Action of Digestion
• Peristalsis
• Circular and longitudinal muscles working
togethe...
Stomach MusclesStomach Muscles
Muscular Action of DigestionMuscular Action of Digestion
• Segmentation
• Contraction of circular muscles in small
intesti...
An Example of a SphincterAn Example of a Sphincter
MuscleMuscle
Secretions of DigestionSecretions of Digestion
• Five organs
• Salivary glands, stomach, pancreas, liver,
small intestine
...
Secretions of DigestionSecretions of Digestion
• Saliva
• Moisten food for easy passage
• Protective role
• Carbohydrate d...
The Salivary Glands
Secretions of DigestionSecretions of Digestion
• Pancreatic juice and intestinal enzymes
• Released via ducts into duodenu...
Summary of Digestive Secretions
& Their Major Actions
The Final StageThe Final Stage
• Undigested residues
• Exercise intestinal muscles
• Retention of water
• Colon
• Intestin...
AbsorptionAbsorption
• Small intestine
• Majority of absorption
• Ten feet long
• Surface area
• Absorption techniques
• S...
Carrier loads
nutrient on
outside of cell . . .
Carrier loads
nutrient on
outside of cell . . .
Outside
cell
Cell
membrane...
Carrier loads
nutrient on
outside of cell . . .
Carrier loads
nutrient on
outside of cell . . .
Outside
cell
Cell
membrane...
Anatomy of the AbsorptiveAnatomy of the Absorptive
SystemSystem
• Villi
• Select and regulate nutrients absorbed
• Microvi...
A Closer Look at the IntestinalA Closer Look at the Intestinal
CellsCells
• Villi cells
• Regulate nutrient absorption bas...
A Closer Look at the Intestinal
Cells
• Transport pathways
• Bloodstream
• Water-soluble nutrients and smaller products
of...
The Vascular SystemThe Vascular System
• Closed system of vessels
• Heart pump
• Blood
• Delivers oxygen and nutrients
• R...
The Vascular SystemThe Vascular System
The LiverThe Liver
The Lymphatic SystemThe Lymphatic System
• One-way route
• No pump
• Circulation between cells
• Entry into bloodstream
• ...
Health and Regulation of the GIHealth and Regulation of the GI
TractTract
• Gastrointestinal bacteria – flora
• Most are n...
Gastrointestinal Hormones andGastrointestinal Hormones and
Nerve PathwaysNerve Pathways
• Homeostatic regulation
• Endocri...
An Example of a NegativeAn Example of a Negative
Feedback LoopFeedback Loop
The Primary actions ofThe Primary actions of
Selected GI HormonesSelected GI Hormones
The System at Its BestThe System at Its Best
• Sensitive and responsive to environment
• Immunity against intestinal disea...
Common DigestiveCommon Digestive
ProblemsProblems
Highlight 3Highlight 3
ChokingChoking
• Food slips into trachea
• Cuts off breathing
• International sign for choking
• Heimlich maneuver
• Foods...
Normal Swallowing andNormal Swallowing and
ChokingChoking
First Aid for ChokingFirst Aid for Choking
VomitingVomiting
• Vomiting
• Adaptive mechanism of the body
• Medical treatment
• Dehydration
• Self induced
Diarrhea
• Diarrhea
• Symptom of medical conditions & treatments
• Irritable bowel syndrome (IBS)
• Colitis
• Treatment
Irritable Bowel Syndrome and
Colitis
• Irritable bowel syndrome
• Characterization
• Cause
• Unknown
• Triggers
• Colitis
...
Celiac Disease
• Autoimmune disease
• Inflammation of small intestine
• Gluten-containing foods
• Symptoms
• Treatment
• R...
ConstipationConstipation
• Not a disease
• Symptoms of constipation
• Causes
• Lifestyle
• Side effect of medications
• Pr...
Constipation
• Hemorrhoids
• Diverticulosis
• Laxatives
• Harmful practices
• Colonic irrigation
Belching and GasBelching and Gas
• Belching
• Swallowed air
• Prevention
• Intestinal gas
• Consumption of certain foods
•...
Heartburn andHeartburn and “Acid“Acid
Indigestion”Indigestion”
• Gastroesophageal reflux (heartburn)
• Causes
• Prevention...
Gastroesophageal Reflux
UlcersUlcers
• Peptic ulcers
• Gastric ulcers
• Duodenal ulcers
• Causes
• Bacterial infection
• Anti-inflammatory drugs
•...
Strategies to Prevent or
Alleviate Common GI Problems
Chapter32012
Chapter32012
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Chapter32012

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  • Figure 3-2 The Colon The colon begins with the ascending colon rising upward toward the liver. It becomes the transverse colon as it turns and crosses the body toward the spleen. The descending colon turns downward and becomes the sigmoid colon, which extends to the rectum. Along the way, the colon mixes the intestinal contents, absorbs water and salts, and forms stools.
  • Figure 3.2: The Colon. The colon begins with the ascending colon rising upward toward the liver. It becomes the transverse colon as it turns and crosses the body toward the spleen. The descending colon turns downward and becomes the sigmoid colon, which extends to the rectum. Along the way, the colon mixes the intestinal contents, absorbs water and salts, and forms stools.
  • Figure 3-8 A bsorption of Nutrients Absorption of nutrients into intestinal cells typically occurs by simple diffusion, facilitated diffusion, or active transport. Occasionally, a large molecule is absorbed by endocytosis — a process in which the cell membrane engulfs the molecule, forming a sac that separates from the membrane and moves into the cell.
  • Figure 3.9: Absorption of Nutrients. Absorption of nutrients into intestinal cells typically occurs by simple diffusion, facilitated diffusion, or active transport. Occasionally, a large molecule is absorbed by endocytosis — a process in which the cell membrane engulfs the molecule, forming a sac that separates from the membrane and moves into the cell.
  • Transcript of "Chapter32012"

    1. 1. Digestion,Digestion, Absorption, andAbsorption, and TransportTransport Chapter 3Chapter 3
    2. 2. DigestionDigestion • Breaking down foods into nutrients • Prepare for absorption • Challenges of digestion • Tasks of the mouth • Diaphragm • Steady movement • Lubrication of food • Digestive enzyme functions • Excretion of waste
    3. 3. Anatomy of the Digestive TractAnatomy of the Digestive Tract • Gastrointestinal (GI) tract • Flexible and muscular • Path • Mouth → esophagus → stomach → small intestine → large intestine → rectum → anus • Lumen • Continuous
    4. 4. The Gastrointestinal TractThe Gastrointestinal Tract
    5. 5. Anatomy of the Digestive TractAnatomy of the Digestive Tract • Mouth • Process of digestion begins • Mastication • Four basic taste sensations • Savory • Aroma, texture, and temperature • Pharynx • Bolus
    6. 6. Anatomy of the Digestive TractAnatomy of the Digestive Tract • Esophagus • Two sphincters • Upper esophageal sphincter • Lower esophageal sphincter • Stomach • Movement of bolus • Chyme • Pyloric sphincter
    7. 7. Anatomy of the Digestive TractAnatomy of the Digestive Tract • Small intestine • Common bile duct • Pancreas and gall bladder • Three segments • Large intestine (colon) • Ileocecal valve • Withdrawal of water • Rectum and anus
    8. 8. Transverse colon Ascending colon Descending colon Sigmoid colonAnus Rectum Appendix Opening from small intestine to large intestine End of small intestine Stepped Art Figure 3-2 p72
    9. 9. Transverse colon Ascending colon Descending colon Sigmoid colonAnus Rectum Appendix Opening from small intestine to large intestine End of small intestine Stepped Art Fig. 3-2, p. 72
    10. 10. Muscular Action of DigestionMuscular Action of Digestion • Peristalsis • Circular and longitudinal muscles working together • Rate and intensity of contractions vary • Factors that may interfere with peristalsis • Stomach action • Circular, longitudinal, and diagonal muscles • Timing the release of chyme
    11. 11. Stomach MusclesStomach Muscles
    12. 12. Muscular Action of DigestionMuscular Action of Digestion • Segmentation • Contraction of circular muscles in small intestine • Mix chyme • Promote contact with absorption cells • Sphincter contractions • Periodically open and close • Control pace of GI tract contents
    13. 13. An Example of a SphincterAn Example of a Sphincter MuscleMuscle
    14. 14. Secretions of DigestionSecretions of Digestion • Five organs • Salivary glands, stomach, pancreas, liver, small intestine • Secretions • Water • Enzymes • Protein facilitator of chemical reactions • Hydrolysis
    15. 15. Secretions of DigestionSecretions of Digestion • Saliva • Moisten food for easy passage • Protective role • Carbohydrate digestion • Gastric juice • Protein digestion • Mucus • pH units
    16. 16. The Salivary Glands
    17. 17. Secretions of DigestionSecretions of Digestion • Pancreatic juice and intestinal enzymes • Released via ducts into duodenum • Enzymes act on all three energy nutrients • Sodium bicarbonate • Bile • Liver • Gallbladder
    18. 18. Summary of Digestive Secretions & Their Major Actions
    19. 19. The Final StageThe Final Stage • Undigested residues • Exercise intestinal muscles • Retention of water • Colon • Intestinal bacteria • Recyclable materials • Water and dissolved salts
    20. 20. AbsorptionAbsorption • Small intestine • Majority of absorption • Ten feet long • Surface area • Absorption techniques • Simple diffusion • Facilitated diffusion • Active transport
    21. 21. Carrier loads nutrient on outside of cell . . . Carrier loads nutrient on outside of cell . . . Outside cell Cell membrane . . . and then releases it on inside of cell. . . . and then releases it on inside of cell. Inside cell FACILITATED DIFFUSION Some nutrients (such as the water- soluble vitamins) are absorbed by facilitated diffusion. They need a specific carrier to transport them from one side of the cell membrane to the other. (Alternatively, facilitated diffusion may occur when the carrier changes the cell membrane in such a way that the nutrients can pass through.) ACTIVE TRANSPORT Some nutrients (such as glucose and amino acids) must be absorbed actively. These nutrients move against a concentration gradient, which requires energy. Stepped Art Some nutrients (such as water and small lipids) are absorbed by simple diffusion. They cross into intestinal cells freely. SIMPLE DIFFUSION Figure 3-8 p77
    22. 22. Carrier loads nutrient on outside of cell . . . Carrier loads nutrient on outside of cell . . . Outside cell Cell membrane . . . and then releases it on inside of cell. . . . and then releases it on inside of cell. Inside cell FACILITATED DIFFUSION Some nutrients (such as the water- soluble vitamins) are absorbed by facilitated diffusion. They need a specific carrier to transport them from one side of the cell membrane to the other. (Alternatively, facilitated diffusion may occur when the carrier changes the cell membrane in such a way that the nutrients can pass through.) ACTIVE TRANSPORT Some nutrients (such as glucose and amino acids) must be absorbed actively. These nutrients move against a concentration gradient, which requires energy. Stepped Art Some nutrients (such as water and small lipids) are absorbed by simple diffusion. They cross into intestinal cells freely. SIMPLE DIFFUSION Fig. 3-9, p. 78
    23. 23. Anatomy of the AbsorptiveAnatomy of the Absorptive SystemSystem • Villi • Select and regulate nutrients absorbed • Microvilli • Enzymes and “pumps” • Crypts • Secretion of intestinal juices • Goblet cells • Mucus secretion
    24. 24. A Closer Look at the IntestinalA Closer Look at the Intestinal CellsCells • Villi cells • Regulate nutrient absorption based on needs • Microvilli • Enzymes and ‘pumps’ • Specialized cells • Food combining • Enhanced use in the body
    25. 25. A Closer Look at the Intestinal Cells • Transport pathways • Bloodstream • Water-soluble nutrients and smaller products of fat digestion • Liver • Lymphatic system • Larger fats and fat-soluble vitamins • Chylomicrons • Bypass liver at first
    26. 26. The Vascular SystemThe Vascular System • Closed system of vessels • Heart pump • Blood • Delivers oxygen and nutrients • Removes carbon dioxide and wastes • Blood flow • Special routing for digestive system • Liver
    27. 27. The Vascular SystemThe Vascular System
    28. 28. The LiverThe Liver
    29. 29. The Lymphatic SystemThe Lymphatic System • One-way route • No pump • Circulation between cells • Entry into bloodstream • Subclavian vein • Nutrients in lymphatic vessels • Bypass liver at first
    30. 30. Health and Regulation of the GIHealth and Regulation of the GI TractTract • Gastrointestinal bacteria – flora • Most are not harmful • Benefits of gastrointestinal bacteria • Factors influencing bacteria presence • Diet – probiotics • Prebiotics • Others • Digestion of fibers and complex proteins • Vitamin production
    31. 31. Gastrointestinal Hormones andGastrointestinal Hormones and Nerve PathwaysNerve Pathways • Homeostatic regulation • Endocrine system • Nervous system • Feedback mechanisms • Examples • GI hormones • Gastrin • Secretin • Cholecystokinin (CCK)
    32. 32. An Example of a NegativeAn Example of a Negative Feedback LoopFeedback Loop
    33. 33. The Primary actions ofThe Primary actions of Selected GI HormonesSelected GI Hormones
    34. 34. The System at Its BestThe System at Its Best • Sensitive and responsive to environment • Immunity against intestinal diseases • Defense against foreign invaders • Health of digestive system • Healthy supply of blood • Lifestyle factors • Types of foods eaten • Balance, moderation, adequacy, and variety
    35. 35. Common DigestiveCommon Digestive ProblemsProblems Highlight 3Highlight 3
    36. 36. ChokingChoking • Food slips into trachea • Cuts off breathing • International sign for choking • Heimlich maneuver • Foods commonly associated with choking • Prevention of choking
    37. 37. Normal Swallowing andNormal Swallowing and ChokingChoking
    38. 38. First Aid for ChokingFirst Aid for Choking
    39. 39. VomitingVomiting • Vomiting • Adaptive mechanism of the body • Medical treatment • Dehydration • Self induced
    40. 40. Diarrhea • Diarrhea • Symptom of medical conditions & treatments • Irritable bowel syndrome (IBS) • Colitis • Treatment
    41. 41. Irritable Bowel Syndrome and Colitis • Irritable bowel syndrome • Characterization • Cause • Unknown • Triggers • Colitis • Inflammation of large intestine
    42. 42. Celiac Disease • Autoimmune disease • Inflammation of small intestine • Gluten-containing foods • Symptoms • Treatment • Rehydration
    43. 43. ConstipationConstipation • Not a disease • Symptoms of constipation • Causes • Lifestyle • Side effect of medications • Prevention • Fiber and water • Physical activity
    44. 44. Constipation • Hemorrhoids • Diverticulosis • Laxatives • Harmful practices • Colonic irrigation
    45. 45. Belching and GasBelching and Gas • Belching • Swallowed air • Prevention • Intestinal gas • Consumption of certain foods • Individually determined
    46. 46. Heartburn andHeartburn and “Acid“Acid Indigestion”Indigestion” • Gastroesophageal reflux (heartburn) • Causes • Prevention • Indigestion • Causes • Antacids and acid controllers • Damage to esophagus • Barrett’s esophagus
    47. 47. Gastroesophageal Reflux
    48. 48. UlcersUlcers • Peptic ulcers • Gastric ulcers • Duodenal ulcers • Causes • Bacterial infection • Anti-inflammatory drugs • Excessive gastric acid secretion • Ulcer treatment regimen
    49. 49. Strategies to Prevent or Alleviate Common GI Problems
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