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Ch14 Digestive System Overview
 

Ch14 Digestive System Overview

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    Ch14 Digestive System Overview Ch14 Digestive System Overview Presentation Transcript

    • Chapter 14 The Digestive System and Body Metabolism
      • 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
      • 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
      • Organs of the Digestive System – know diagram for test
      Slide 14.2b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 14.1
      • 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
      • 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
      • 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
      • Mouth (Oral Cavity) Anatomy
      Slide 14.6 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
      • Tonsils
        • Palatine tonsils
        • Lingual tonsil
      Figure 14.2a
      • 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
      • 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
      • 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)
      • 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)
      • 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
      • 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
      • 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
      • 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
      • 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
      • 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
      • 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
      • 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
      • 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
      • 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
      • Chemical Digestion in the Small Intestine
      Slide 14.23b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 14.6
      • 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
      • 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
      • 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)
      • 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
      • Large Intestine
      Slide 14.28 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 14.8
      • 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
      • 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
      • 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
      • 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
      • Accessory Digestive Organs
      Slide 14.32 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
      • Salivary glands
      • Teeth
      • Pancreas
      • Liver
      • Gall bladder
      • Spleen
      • 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
      • 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
      • 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
      • 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
      • 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
      • 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)
      • 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
      • 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
      • 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
      • 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
      • 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
      • 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