Principles of Digestive System Functions Human Anatomy Anatomy Bio… · Anatomy of the Digestive...
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4/23/2012 1 CHAPTER 24 Part 1 The Digestive System Copyright © 2007 by John Wiley & Sons, Inc. Principles of Human Anatomy Eleventh Edition Principles of Human Anatomy Eleventh Edition Gerard J. Tortora & Mark T. Nielsen Digestive System Functions Digestive System Functions n Digestion Digestion n Breakdown of food into molecules small Breakdown of food into molecules small enough to enter the body enough to enter the body n Mechanical Mechanical n Chemical (enzymatic) Chemical (enzymatic) n Absorption Absorption n Passage of molecules into the blood & lymph Passage of molecules into the blood & lymph n Passive Passive n Active Active Organs of the Digestive Organs of the Digestive System System n GI Tract = Alimentary Canal GI Tract = Alimentary Canal n Mouth Mouth Pharynx Pharynx n Esophagus Esophagus Stomach Stomach n Small Intestine Small Intestine Large Intestine Large Intestine n Accessory Structures Accessory Structures n Teeth Teeth Tongue Tongue n Salivary glands Salivary glands Liver Liver n Gallbladder Gallbladder Pancreas Pancreas 25_01a 25_01a Layers of the GI Tract Layers of the GI Tract n Mucosa Mucosa n Epithelium Epithelium n Lamina Lamina propria propria n Muscularis Muscularis mucosa mucosa n Submucosa Submucosa n Areolar Areolar CT CT n Blood vessels & Blood vessels & glands glands n Submucosal Submucosal plexus ( plexus (Meissner Meissner) Layers of the GI Tract cont. Layers of the GI Tract cont. n Muscularis Muscularis Externa Externa n Inner circular muscle Inner circular muscle n Myenteric Myenteric plexus plexus (plexus of (plexus of Auerbach Auerbach) n Outer longitudinal Outer longitudinal muscle muscle n Serosa Serosa or Adventitia or Adventitia n Connective tissue Connective tissue n Mesothelium Mesothelium
Transcript of Principles of Digestive System Functions Human Anatomy Anatomy Bio… · Anatomy of the Digestive...
4/23/2012
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CHAPTER 24 Part 1The Digestive System
Copyright © 2007 by John Wiley & Sons, Inc.
Principles ofHuman Anatomy
Eleventh Edition
Principles ofHuman Anatomy
Eleventh EditionGerard J. Tortora
&
Mark T. Nielsen
Digestive System FunctionsDigestive System Functions
nn DigestionDigestionnn Breakdown of food into molecules small Breakdown of food into molecules small
enough to enter the bodyenough to enter the bodynn MechanicalMechanicalnn Chemical (enzymatic)Chemical (enzymatic)
nn AbsorptionAbsorptionnn Passage of molecules into the blood & lymphPassage of molecules into the blood & lymph
nn PassivePassivenn ActiveActive
Organs of the Digestive Organs of the Digestive SystemSystem
nn GI Tract = Alimentary CanalGI Tract = Alimentary Canalnn MouthMouth PharynxPharynxnn EsophagusEsophagus StomachStomachnn Small IntestineSmall Intestine Large IntestineLarge Intestine
nn Accessory StructuresAccessory Structuresnn TeethTeeth TongueTonguenn Salivary glandsSalivary glands LiverLivernn GallbladderGallbladder PancreasPancreas
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Layers of the GI TractLayers of the GI Tract
nn MucosaMucosann EpitheliumEpitheliumnn Lamina Lamina propriapropriann MuscularisMuscularis mucosamucosa
nn SubmucosaSubmucosann AreolarAreolar CTCTnn Blood vessels & Blood vessels &
glandsglandsnn SubmucosalSubmucosal
plexus (plexus (MeissnerMeissner))
Layers of the GI Tract cont.Layers of the GI Tract cont.
nn MuscularisMuscularis ExternaExternann Inner circular muscleInner circular musclenn MyentericMyenteric plexus plexus
(plexus of (plexus of AuerbachAuerbach))nn Outer longitudinal Outer longitudinal
musclemusclenn SerosaSerosa or Adventitiaor Adventitia
nn Connective tissueConnective tissuenn MesotheliumMesothelium
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25_0225_02 Serous Membrane of the Abdominal Cavity
n Peritoneumn Largest serous membrane in the bodyn Parietal peritoneum
n Lines wall of abdominopelvic cavityn Visceral peritoneum
n Covers organs in the cavity
n Peritoneal cavityn Potential space
n Ascities – fluid buildup in this space
Folds of the Peritoneumn Mesentery
n Holds intestines together and attaches them to the posterior body wall
n Falciform Ligamentn Attaches liver to the anterior abdominal wall
n Lesser Omentumn Suspends the stomach & duodenum from the liver
n Mesocolonn Binds the large intestine to the posterior abdominal wall
n Greater Omentumn Drapes over the transverse colon and small intestine
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25_03b25_03b--ee 25_03f25_03f
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Anatomy of the Digestive System
n Mouthn Where digestion begins
n Mechanical and enzymatic (CHO & lipid)n Cheeks, hard & soft palates, lips, oral cavityn Tongue
n Skeletal muscle covered by mucus membranen Papillae – projections of lamina propria
n Filiform – no tastebuds anterior 2/3 of tonguen Fungiform – most have tastebuds, numerous at tipn Circumvallate – posterior of tongue all have tastebuds
n Sour, salty, bitter, sweet, umami
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Salivary Glands
n Secrete saliva as an exocrine glandn 99.5% watern 0.5% solutes
n Ions – Na+ , K+ , Cl+ , bicarbonaten Dissolved organics – urea, albumen, globulin, mucusn Digestive enzymes – salivary amylase & lingual lipase
n Parotid glands – duct empties by upper molarn Submandibular glands – empties near lingual
frenulumn Gleeking
n Sublingual glands – empties under tongue
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Salivary GlandsSalivary Glands Teethn Major regions
n Crownn Above the gumlinen Covered by enamel
n Neckn Junction between
crown and root
n Rootn Embedded in bone
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Teethn Enamel (Crown)
n Calcium phosphaten Calcium carbonaten Hardest substance in
body (95% Ca++ salts)n Dentin
n Harder than bonen 70% Ca++ salts
n Cementum (Root)n Attaches root to
periodontal ligament
Pulp CavityPulp Cavity
Dentitionsn Deciduous (primary) or
baby teethn 6 mo – 32 mo
n Permanent (secondary) or adult teethn 6 yrs to > 20 yrs
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TeethTeeth Esophagus
n Muscular tube to connect mouth to stomachn UESn LES
n Unique Histological Characteristicsn Stratified Squamous Epitheliumn Adventitia
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Stomachn Cardian Fundusn Bodyn Pyloric Antrumn Pyloric Canaln Pylorusn Lesser curvaturen Greater curvature
Stomach Histology
n Gastric Pitsn Gastric Glandsn 3 Muscle Layers in
Muscularis Externan Inner Obliquen Middle Circularn Outer Longitudinal
Stomach Mucosan Surface mucous cells
n In gastric pitsn Mucous neck cells
n In gastric glandsn Parietal (oxycintic) cells
n Secretes HCln Secretes intrinsic factor
n Chief (zymogenic) cellsn Secretes pepsinogen
n G-cellsn Secretes Gastrin
n Hormone
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Accessory exocrine organs secreting into the small intestinen Pancreas
n Acininar cells secrete digestive enzymes
n Ductal cells secrete bicarbonate
n Pancreatic ductn Hepatopancratic
ampullan Sphincter of Oddi
Pancreas
Accessory exocrine organs secreting into the small intestine
n Livern Right & Left Lobesn Caudate & Quadrate Lobesn Biliary system
n Left & Right hepatic Ductsn Common Hepatic Ductn Cystic Ductn Common Bile Duct
n Specialized blood supplyn Hepatic Arteryn Hepatic Portal Vein
n Gall Bladdern Stores & Concentrates Bile
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Liver Histology 25_14c
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25_15 Small Intestinen Duodenum
n Means Twelven As long as the width of 12 fingers (10 inches)
n Retroperitonealn Jejunum
n Means Emptyn Found empty in death
n 3 feetn Ileum
n Means Twistedn 6 feet
Small Intestine Surface Area Adaptationsn Circular Folds
n Folds in mucosa and submucosa
n 1 cm (0.4 inches)n Causes chyme to spiral
n Villin Gives velvety appearancen 0.5-1 mm
n Microvillin Projections of apical
membranen 1 µm
25_18a Histology of the Ileum
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Large Intestinen Cecum
n Blind pouchn Ascending Colon
n Retroperitonealn Transverse Colonn Descending Colon
n Retroperitonealn Sigmoid Colonn Rectumn Anal Canal
Haustra & Teniae Coli
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25_20d Learning ObjectivesLearning Objectives
nn Describe the functions of the digestive Describe the functions of the digestive systemsystem
nn List the organs of the digestive systemList the organs of the digestive systemnn What are the functions of the accessory What are the functions of the accessory
organsorgansnn Describe the hard and soft palatesDescribe the hard and soft palatesnn Describe the structures associated with Describe the structures associated with
the mouth and lipsthe mouth and lips
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Learning ObjectivesLearning Objectives
nn Describe the 3 pairs of salivary glands and Describe the 3 pairs of salivary glands and their secretionstheir secretions
nn Describe the difference between chemical Describe the difference between chemical and mechanical digestionand mechanical digestion
nn Describe where chemical digestion of Describe where chemical digestion of carbohydrates, lipids and proteins begincarbohydrates, lipids and proteins begin
nn Describe the anatomy of a toothDescribe the anatomy of a toothnn Describe the 2 dentitionsDescribe the 2 dentitions
Learning ObjectivesLearning Objectives
nn Discuss the different cells of the stomach Discuss the different cells of the stomach mucosa and what their functions aremucosa and what their functions are
nn Describe the area of the GI tract where Describe the area of the GI tract where most of the digestion and absorption takes most of the digestion and absorption takes placeplace
nn Describe the histology of the liver and its Describe the histology of the liver and its blood suppliesblood supplies
nn List the different parts of the small and List the different parts of the small and large intestinelarge intestine
Learning ObjectivesLearning Objectives
nn List the adaptations of the mucosa List the adaptations of the mucosa designed to increase surface areadesigned to increase surface area
nn Describe the peritoneum and its many foldsDescribe the peritoneum and its many foldsnn Define retroperitoneal and list organs of the Define retroperitoneal and list organs of the
digestive system which are retroperitonealdigestive system which are retroperitonealnn Describe the 4 main layers of the GI tract Describe the 4 main layers of the GI tract
and discuss how and discuss how these layers differ from these layers differ from area to areaarea to area
Learning ObjectivesLearning Objectives
nn Define the following terms: peristalsis, Define the following terms: peristalsis, bolus, bolus, chymechyme, , haustrahaustra, , haustralhaustral churning, churning, teniatenia colicoli
