Chapter 22 u2013 Digestive System.docx - Chapter 22 u2013...

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Chapter 22 – Digestive SystemI)Introa.Gastrointestinal (GI) / digestive tracti.Alimentary canal– continuous tube, food passes through canal1.POES-SILI- Pharynx, oral cavity, esophagus, stomach, S.I., L.I.ii.Accessory organs1.GPSLTT– Gallbladder, pancreas, salivary glands, liver, teeth, tongueb.Basic Functions and Processes i.ISPDADii.Ingestion– food and water brought into digestive system, mouthiii.Secretion– Endocrine and exocrine glands secrete mucus, enzymes, acid, hormonesiv.Propulsion– via peristalsis, rhythmic contractions of smooth muscle, moves foodv.Digestion– Food breakdown; mechanical and chemicaldigestionvi.Absorption– nutrients move through walls into bloodvii.Defecation– exit the body via fecesc.Regulation of Motilityi.Enteric Nervous System (ENS)1.Part of Autonomic Nervous System (ANS)parasympathetic2.Extends from esophagus to anus3.Short reflexes confined to local neuronsd.Histology of Alimentary Canali.Lumen – space in the middleii.4 tissue layersiii.Mucosa1.Epithelium, lamina propria(loose connective), muscularis mucosae(smooth)iv.Submucosa1.Dense irregular CT, blood, submucosal plexus(nerve clusters)v.Muscularisexterna1.Smooth musclecircular and longitudinal, regulated by myenteric plexus(nerve clusters)vi.Serosa/ adventitia1.Serosa(simple squamous and loose connective) on peritoneal organs2.Adventitia– Dense irregular in organs outside peritoneal
Chapter 22 – Digestive Systemvii.Peritoneum– the entire serous membrane1.Visceral peritoneum(serosa, on the organ), parietal peritoneum(outer wall)2.Peritoneal cavity– serous fluid filled space between serous membranesviii.Mesenteries– structures forms when serosa folds over onto itself, provides structure and blood vessels1.Greater Omentum (“fatty apron”)andLesser Omentum– four layers and adiposeix.Splanchnic circulation– blood vessels that supply and drain the digestive organsx.SNS and PSN- Celiac Plexus, Superior Mesenteric Plexus, Inferior Mesenteric PlexusII)Pharynx, Oral Cavity, and Esophagusa.Structure of Oral Cavityi.Cheeks– buccinators musclesii.Lips– orbicularis oris muscle; stratified squamous keratinized; labial frenulumiii.Vestibule– space between lips, cheeks gumsiv.Gums– gingivav.Palate– hard palate (palatine process of maxilla, palatine bone); soft palate; uvulab.Teethand masticationi.Masseterand temporalismuscles provide masticationii.Alveoli– bony sockets in mandible and maxilla bonesiii.Dentitions– 3, 2, 1, 4, 1, 2, 31.Tricuspids (molars), bicuspids (premolars), cuspids (canines), incisors2.Secondary dentition – 32 permanent teeth (6, 4, 2, 4, 2, 4, 6 + 4 wisdom)iv.Crown– above gum linev.Root– in alveolusvi.Enamel– soft coveringvii.Dentin– inner layer under enamel, made by odontoblastsviii.Cementum– outer portion on root, hold in place by periodontal ligamentix.Pulp– inner gelatinous, blood vessels and nervesc.Tonguei.Skeletal muscle, stratified squamousii.Lingual frenulum– anchors to floor of oral cavityiii.Papillae1.Filiform, Fungiform, Circumvallate, Foliate papillae2.

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