VPHY 3100: Week of 11/9
VPHY 3100: Week of 11/9 VPHY 3100
Popular in Elements of Physiology
Popular in Animal Science and Zoology
verified elite notetaker
This 3 page Class Notes was uploaded by Lorin Crear on Saturday November 14, 2015. The Class Notes belongs to VPHY 3100 at University of Georgia taught by Dr. Li, Dr. Wells, Dr. Brown in Summer 2015. Since its upload, it has received 49 views. For similar materials see Elements of Physiology in Animal Science and Zoology at University of Georgia.
Reviews for VPHY 3100: Week of 11/9
Report this Material
What is Karma?
Karma is the currency of StudySoup.
Date Created: 11/14/15
Chapter 18 The Digestive System 0 Purpose to break food into basic organic molecules 0 Polymers 9 monomers by hydrolysis 0 Anatomy 0 Digestive tract aka GI tract or gastrointestinal tract Oral cavity Pharynx Esophagus Stomach Small intestine 0 Duodenum 0 J ejunum o Ileum Large intestine 0 Cecum 0 Colon 0 Rectum Anus 0 Internal anal sphincter 0 External anal sphincter 30 feet long in adults Considered outside body 0 Open at both ends to environment 0 Nondigestables never actually enter body Accessory organs 0 Teeth o Tongue 0 Salivary glands 0 Liver 0 Gallbladder o Pancreas Layers of tract 0 Mucosa 0 Submucosa o Muscularis 0 Inner circular muscularis 0 Outer longitudinal muscularis 0 Serosa 0 Thin outer membrane 0 Separates tract from abdominal cavity 0 Digestive processes 0 Digestion Breaking food down into smaller units 0 Absorption Oral Cavity Passing brokendown food into blood or lymph o Occurring in both processes Motility movement of food somewhat automatic Ingestion mastication chewing deglutition swallowing Peristalsis and segmentation Defecation Secretion somewhat automatic Regulation Neural Storage Endocrine hormones o Transported in blood Exocrine enzymes electrolytes HCl water 0 Transported through blood 0 Fastacting shortlived effects 0 Extrinsic nervous system I Parasympathetic division 0 Generally stimulatory o Vagus nerve stimulates 0 Upper GI o Pancreas o Gallblader 0 First part of large intestine 0 Spinal nerves in sacral region stimulate 0 Lower large intestine I Sympathetic division 0 Generally inhibitory o Inhibits peristalsis and secretion 0 Stimulates contraction of sphincters o Intrinsic nervous system I In uenced by extrinsic nervous system I Continues motility without input from extrinsic o Submucosal plexus I Sheet of neurons between submucosa and inner circular muscularis I Extrinsic and intrinsic NS meet here 0 Myenteric plexus I Sheet of neurons between inner circular muscularis and outer longitudinal muscularis I Extrinsic and intrinsic NS meet here Hormonal o Slowacting longlasting effects 0 From brain or other digestive organs Stomach and colon o Mastication chewing Saliva secreted by salivary glands 0 Contains salivary amylase mucus and growth factors Chewing mixes food with saliva o Deglutition swallowing 0 Esophagus Oral phase is voluntary Pharyngeal and esophageal phases are involuntary Upper esophageal sphincter relaxes to let food bolus through Epiglottis covers entrance to respiratory tract Center in medulla oblongata controls pattern of contractions necessary for swallowing 0 Upper third skeletal muscle 0 O O 0 Middle third mix of skeletal and smooth muscle Lower third smooth muscle Passes through diaphragm via esophagus hiatus Peristalsis Food bolus moved through esophagus to stomach by series of localized re ex in response to distention of wall by bolus Peristaltic wave 0 Muscle contractions 0 Circular smooth muscle on oral side of bolus contracts and muscle on anal side relaxes o Followed by longitudinal contraction shortening of smooth muscle 0 Lower esophageal sphincter 0 Stomach Stays closed to prevent regurgitationacid re ux heart burn 0 Most distensible part of GI tract 0 Empties into duodenum of small intestine 0 Anatomy Cardia Fundus Body Pylorus Pyloric sphincter Gastric mucosa lining has gastric pits in folds 0 Gastric pits lined by gastric glands that secrete gastric juice 0 Functions Stores food Mixes via contractions food with gastric secretions chyme Initiates digestion of proteins Kills bacteria Moves chyme into small intestine via contractions