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Ch14 Digestive System Overview Presentation Transcript

  • 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