digestionoutlineDigestive systemsDigestive compartmentsFood processingSlide 6Nutrition introductioningestionMechanical ProcessingSlide 10Slide 11secretionMouth Watery goodnessSecretionSlide 15Chemical digestionSlide 17absorptionSlide 19excretionSlide 21movementSlide 23peristalsisDigestive SystemAlimentary canalSlide 27Slide 28Gastrointestinal tractGastrointestinal Tract27 feet!Specialized regions of tubeGI tract componentsAccessory organsSlide 35Slide 36Slide 37General HistologyTunicsSlide 40Slide 41Slide 42Slide 43Tunic variationsGeneralized tunic structureSlide 46MucosaSlide 48Mucosa epitheliumesophagus- stratified squamousStomach- Simple ColumnarGlandular EpitheliumSlide 53Lamina PropriaSlide 55Slide 56Lymphoid tissueGlandsMuscularis MucosaeSlide 60Slide 61Rugae & Plica CircularisSlide 63Slide 64SubmucosasubmucosaSlide 67Submucosal GlandsPeyer’s Patch- Lymph TissueMeissner’s plexusSlide 71Muscularis ExternaSlide 73Slide 74Slide 75external anal sphincterSlide 77PeristalsisInner Circular LayerOuter LongitudinalAlternating contractionSlide 82SerosaSlide 84Slide 85Slide 86digestionChapteroutline•Food processing overview•Digestive system•Nutrition requirements•Nutritional disordersDigestive systemsDigestive compartments•Prevent digestion of own tissuesFood processing•Ingestion•Mechanical processing•Secretion•Digestion•Absorption•Excretion•movementNutrition introduction•Heterotrophs•Provides molecules body Needs to functioningestion•Intake of food source ie organic & inorganic molecules–Food, water & minerals•Physical actionMechanical Processing•Physical process•Physical reduction of food size•Tongue, teeth, churning (mixing) of stomach & intestineMechanical ProcessingMechanical Processingsecretion•Production & release of digestive chemicals & enzymes•Ex production of salivary amylase to chemically break down food particlesMouth Watery goodnessSecretiondigestion•Break down of food •chemical & enzymatic breakdown of ingested particles•Absorbable units- monomers–Monosaccharides–Amino acids–Fatty acidsChemical digestiondigestionabsorption•Transport of monomers through intestinal cells into blood & lymphabsorptionexcretion•Removal of indigestible substances•Defecation- removing solid wastesexcretionmovement•Transfer of ingested particles through the digestive tract•Peristalsis–Wave-like smooth muscle contractions of the digestive tract–Pushes solids & liquids through tractmovementperistalsisDigestive System•Gastrointestinal tract•Accessory organsAlimentary canal•Aka gastrointestinal tract•Tube within a tube design•Gut & accessory organsGastrointestinal tract•Aka GI tract, ailimentary canal•All regions food passes through•Primarily composed of smooth muscle- involuntary–Excludes entrance & exit= skeletal muscle•Continuous, open-ended muscular tube–1 way–Mouth to anus–~27 ft (8.2 m)–Sphincters- regulation•Organized into divisions–Specialized regions= different organs–Specializations result in specific isolated functionsGastrointestinal Tract27 feet!Specialized regions of tubeGI tract components•Oral cavity•Pharynx•Esophagus•Stomach•Small & large intestine (colon/rectum)Accessory organs•Aid in food processing as it travels through the digestive tract•Food does not pass through accessory structuresAccessory organs•Teeth•Tongue•Salivary glands•Liver •Gall bladder•pancreasAccessory organsAccessory organsGeneral Histology •4 tissue layers•Aka tunics–Mucosa•Most variable–Submucosa–Muscularis–Serosa•Visceral peritoneum•Variations in tunics reflect specialization of function•Variations identify GI tract regionsTunicsLayers within tube systemTunicsMucosaSubmucosaMuscularisSerosaTunicsMucosaTunic variationsMucosa most variable layerGeneralized tunic structure•Mucosa•Submucosa•Muscularis externa•serosaMucosa•Inner most layer of GI tract •In contact with food•Mucous membrane–3 layers•Epithelium•Lamina propria–Connective tissue•Muscularis mucosae–Muscle tissueMucosa epithelium•Stratified &/or simple–Esophagus- stratified squamous–Stomach- simple columnar•Glandular epithelium–Mucus- lubrication–Digestive- enzymes & chemicalsesophagus- stratified squamousStomach- Simple ColumnarSecretionGlandular EpitheliumGlandular EpitheliumLamina Propria•Underlying loose areolar connective tissue of Mucosa tunic•Contains blood & nerve tissue–Nutrients to epithelia•Lymphoid tissue–Immune- white blood cell aggregations–Peyer’s patches•Glands–Mucosal glands–Brunner’s glandsLamina PropriaLymphoid tissueGlandsMuscularis Mucosae•External to lamina propria•Narrow band of smooth muscle found in mucosa tunic•Pushes GI tract into macroscopic folds–Rugae•Increases surface areaMuscularis MucosaeRugae & Plica CircularisGeneralized tunic structure•Mucosa•Submucosa•Muscularis externa•serosaSubmucosa•Loose areolar ct•Contains–Large blood vessels –Lymph tissue- especially in lower GI–Large glands- submucosal glands•Duodenal glands- aka Brunner’s Gland–Alkali mucus •Peyer’s patch aka Lymph nodule–Aggregations of immune cells–Nerves- control glandular secretions•Submucosal plexus•Meissner’s plexussubmucosasubmucosaSubmucosal GlandsPeyer’s Patch- Lymph TissueMeissner’s plexusGeneralized tunic structure•Mucosa•Submucosa•Muscularis externa•serosaMuscularis Externa•Comprise GI tract muscular wall•Produces movement (peristalsis) & regulates passage (sphincters) •Muscle type–Primary smooth muscle•Majority of tract unconscious control•Skeletal muscle–Sphincter–Entrances & exits consciously controlled–Mouth, pharynx, sup. Esophagus, external anal sphincter–Myenteric plexus•2 layers of muscle–Circular layer- decreases diameter of tube–Longitudinal layer- changes length of tubeMuscularis ExternaMuscularis ExternaMuscularis Externaexternal anal sphincterPeristalsis•Inner circular layer–Alters diameter of GI tract•Outer Longitudinal–Alters length of GI tract•Alternating contractions produce- peristalsisInner Circular LayerDiameter changeOuter LongitudinalAlters lengthAlternating contractionGeneralized tunic structure•Mucosa•Submucosa•Muscularis externa•serosaSerosa•Covering over GI tract•Visceral peritoneum•Function–Conduit for blood vessels & nerves–Attach & support: maintain position•Composition–Primarily serous