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Chapter 20 Digestive System. By Angie Lawson RN, BSN. Overview. Digestion Mechanical – breakdown of food by physical means Chemical – the chemical alteration of food Absorption – movement of end products out of the digestive tract. Layers. Mucosa – innermost layer, mucous membrane
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Chapter 20Digestive System By Angie Lawson RN, BSN
Overview • Digestion • Mechanical – breakdown of food by physical means • Chemical – the chemical alteration of food • Absorption – movement of end products out of the digestive tract.
Layers • Mucosa – innermost layer, mucous membrane • Submucosa – thick layer connective tissue • Muscle Layer- smooth muscle layer • This is where peristalsis occurs • Serosa – outermost layer
Peritoneal Membranes • Mesentery • Mesocolon • Greater Omentum – resembles an apron draped over the abdominal organs • Lesser Omentum
Mouth • Teeth • Tongue • Salivary Glands • Other structures
Teeth • Mastication • Deciduous teeth • Permanent teeth • Pulp
Tongue • Bolus – ball like mass of food • Frenulum – anchors tongue to the floor of the mouth • Sublingual – to place under the tongue
Salivary Glands • Parotid • Submandibular • Sublingual • Saliva – watery fluid that contains mucus and the digestive enzyme Salivary amylase
Other Structures • Hard palate & Soft Palate - make up the top of the mouth • Uvula – during swallowing it keeps food from moving upward into your nose
Pharynx • Deglutition • Esophagus • Epiglottis
Esophagus • Sphincters: • Pharyngoesophageal • Gastroesophageal • Lower Esophageal (LES) – also known as cardiac sphincter • Pyrosis – heartburn, stomach contents refluxes into the esophagus
Stomach • Fundus • Body • Pylorus • Greater & lesser curvature • Rugae – allows the stomach to expand
Stomach (cont:) • Chyme – thick pastlike substance • Vagus Nerve – primary nerve in the digestive tract • Mucus Cells • Gastric Glands • Gastric Juice
Hiatal Hernia • The stomach moves up through the diaphragm into the thoracic cavity
Small Intestine • Duodenum • Jejunum • Ileum • Villi • Chyle
Large Intestine • Cecum • Colon • Appendix
Liver (Hepatic) • Hepatic Portal System • Liver Lobules • Bile • Biliary Tree
Pancreas • Main Pancreatic Duct • Pancreatic Enzymes • Acinar Cells • Secretin
Digestion & Absorption • Amylases – digests polysaccharides • Cellulose • Proteases – digests proteins • Lipases – digests fats • Emulsification – this process is carried out with the use of bile