Digestive System Part 1 PDF

THE DIGESTIVE SYSTEM PART 1 Bashir Sumar School of Nursing and Midwifery  Important Copyright Notice for Western Sydney University Students The material in this presentation has been made available to you by and on behalf of Western Sydney University for your pers...

THE DIGESTIVE SYSTEM PART 1 Bashir Sumar School of Nursing and Midwifery  Important Copyright Notice for Western Sydney University Students The material in this presentation has been made available to you by and on behalf of Western Sydney University for your personal use and study only. The material contained in this recorded lecture is subject to copyright protection. You may not make any further copies and share the recorded lectures in whole or in part by any hardcopy, digital and or online technologies.  Nutrition at a Glance Carbohydrates, For Energy (kj) to fats (& protein) run daily activities Water and Why do minerals and cellular reactions I eat? For hydration and Build structures osmoregulation such as cells/tissues/organs for growth, repair, Fats maintenance For organ protection, insulation and stored Proteins, fats & essential chemicals energy reserve carbohydrates controlling reactions Minerals/vitamins 3 Food Chemistry Carbohydrates (saccharides/sugars) - (compounds of C,H,O ) Polysaccharides (e.g. starch, cellulose, glycogen) contain many joined sugar units Oligosaccharides - (e.g. fructose chains, glycoprotein cell markers) - smaller polymers of many sugar units Disaccharides - (e.g. sucrose, lactose, maltose) - double sugars Monosaccharides- (e.g.glucose, fructose, galactose) single sugars (monomers) – the building blocks of the other complex saccharides 4  Proteins Compounds of C,H,O, N (and sometimes S), also called Polypeptides (polymers) Peptide bond globular Straight chain Dipeptides (double units) Amino Acids - building blocks of proteins – monomers Fats (Lipids) Compounds of C,H,O,P Complex (e.g. triglycerides) Fatty Acids and Glycerols 6 Digestive System Two groups of organs 1. Alimentary canal (gastrointestinal or GI tract) Mouth to anus Digests food and absorbs fragments Mouth, pharynx, esophagus, stomach, small intestine, and large intestine © 2013 Pearson Education, Inc. Digestive System 2. Accessory digestive organs Teeth, tongue, gallbladder Digestive glands and organs Salivary glands Liver Pancreas © 2013 Pearson Education, Inc. Figure 23.1 Alimentary canal and related accessory digestive organs. Mouth (oral cavity) Parotid gland Tongue* Sublingual gland Salivary Submandibular gland glands* Esophagus Pharynx Stomach Pancreas* (Spleen) Liver* Gallbladder* Transverse colon Duodenum Descending colon Small Jejunum intestine Ileum Ascending colon Cecum Large intestine Sigmoid colon Rectum Appendix Anus Anal canal © 2013 Pearson Education, Inc.  Digestive Processes Six essential activities 1. Ingestion 2. Propulsion 3. Mechanical breakdown 4. Digestion 5. Absorption 6. Defecation © 2013 Pearson Education, Inc. Figure 23.2 Gastrointestinal tract activities. Ingestion Food Mechanical breakdown Pharynx Chewing (mouth) Esophagus Churning (stomach) Propulsion Segmentation Swallowing (small intestine) (oropharynx) Peristalsis Digestion (esophagus, stomach, small intestine, large intestine) Stomach Absorption Lymph vessel Small intestine Large Blood intestine vessel Mainly H2O Feces Anus Defecation © 2013 Pearson Education, Inc. Figure 23.3 Peristalsis and segmentation. From mouth Peristalsis: Adjacent segments of alimentary tract organs alternately contract and relax, moving food along the tract distally. Segmentation: Nonadjacent segments of alimentary tract organs alternately contract and relax, moving food forward then backward. Food mixing and slow food propulsion occur. © 2013 Pearson Education, Inc. Figure 23.4 Neural reflex pathways initiated by stimuli inside or outside the gastrointestinal tract. External stimuli (sight, smell, taste, Central nervous system thought of food) Long reflexes Visceral afferents Extrinsic visceral (autonomic) efferents Internal Chemoreceptors, Local (intrinsic) Effectors: (GI tract) osmoreceptors, or nerve plexus Smooth muscle stimuli mechanoreceptors ("gut brain") or glands Short reflexes Gastrointestinal Response: wall (site of short Change in reflexes) contractile or secretory activity Lumen of the alimentary canal © 2013 Pearson Education, Inc.  Figure 23.6 Basic structure of the alimentary canal. Intrinsic nerve plexuses Myenteric nerve plexus Submucosal nerve plexus Glands in submucosa Mucosa Epithelium Lamina propria Muscularis mucosae Submucosa Muscularis externa Longitudinal muscle Circular muscle Serosa Epithelium (mesothelium) Nerve Connective tissue Artery Gland in mucosa Lumen Vein Duct of gland outside Mucosa-associated Mesentery Lymphatic vessel alimentary canal lymphoid tissue © 2013 Pearson Education, Inc.  Figure 23.6 Basic structure of the alimentary canal. Intrinsic nerve plexuses Myenteric nerve plexus Submucosal nerve plexus Glands in submucosa Mucosa Epithelium Lamina propria Muscularis mucosae Submucosa Muscularis externa Longitudinal muscle Circular muscle Serosa Epithelium (mesothelium) Nerve Connective tissue Artery Gland in mucosa Lumen Vein Duct of gland outside Mucosa-associated Mesentery Lymphatic vessel alimentary canal lymphoid tissue © 2013 Pearson Education, Inc. Figure 23.7a Anatomy of the oral cavity (mouth). Soft palate Palatoglossal arch Uvula Hard palate Oral cavity Palatine tonsil Tongue Oropharynx Lingual tonsil Epiglottis Hyoid bone Laryngopharynx Esophagus Trachea Sagittal section of the oral cavity and pharynx© 2013 Pearson Education, Inc. Figure 23.8 Dorsal surface of the tongue, and the tonsils. Epiglottis Palatopharyngeal arch Palatine tonsil Lingual tonsil Palatoglossal arch Terminal sulcus Foliate papillae Vallate papilla Medial sulcus of the tongue Dorsum of tongue Fungiform papilla Filiform papilla © 2013 Pearson Education, Inc. Salivary Glands Salivary glands Produce most saliva; lie outside oral cavity Parotid Submandibular Sublingual © 2013 Pearson Education, Inc.  Figure 23.9 The salivary glands. Parotid gland Ducts of sublingual gland Parotid duct Sublingual gland Submandibular duct Submandibular gland Mucous cells Serous cells forming demilunes © 2013 Pearson Education, Inc. Digestive Processes: Mouth Ingestion Mechanical digestion Chewing Propulsion Deglutition (swallowing) Chemical digestion (salivary amylase and lingual lipase) ~ No absorption, except for few drugs Please now watch Part 2 © 2013 Pearson Education, Inc.