Lab 5 Digestion and Hormones of Digestion 1
Figure 23.1 Alimentary canal and related accessory digestive organs. Mouth (oral cavity) Tongue* Parotid gland Sublingual gland Submandibular gland Salivary glands* Esophagus Liver* Gallbladder* Pharynx Stomach Pancreas* (Spleen) Small intestine Anus Duodenum Jejunum Ileum Transverse colon Descending colon Ascending colon Cecum Sigmoid colon Rectum Appendix Anal canal Large intestine 7/16/2015 2 MDufilho
Figure 23.2 Gastrointestinal tract activities. Ingestion Mechanical breakdown Chewing (mouth) Churning (stomach) Segmentation (small intestine) Digestion Food Pharynx Esophagus Propulsion Swallowing (oropharynx) Peristalsis (esophagus, stomach, small intestine, large intestine) Stomach Absorption Lymph vessel Small intestine Large intestine Mainly H 2 O Feces Blood vessel Anus Defecation 7/16/2015 3 MDufilho
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 4 Sagittal section of the oral cavity and pharynx
Figure 23.13 Deglutition (swallowing). Bolus of food Slide 1 Tongue Pharynx Epiglottis Glottis Uvula Bolus Epiglottis Trachea Esophagus Upper esophageal sphincter Bolus 1 During the buccal phase, the upper esophageal sphincter is contracted. The tongue presses against the hard palate, forcing the food bolus into the oropharynx. 2 The pharyngeal-esophageal phase begins as the uvula and larynx rise to prevent food from entering respiratory passageways. The tongue blocks off the mouth. The upper esophageal sphincter relaxes, allowing food to enter the esophagus. 3 The constrictor muscles of the pharynx contract, forcing food into the esophagus inferiorly. The upper esophageal sphincter contracts (closes) after food enters. Relaxed muscles Circular muscles contract 4 Peristalsis moves food through the esophagus to the stomach. Relaxed muscles 5 The gastroesophageal sphincter surrounding the cardial oriface opens, and food enters the stomach. Bolus of food Longitudinal muscles contract Circular muscles contract Gastroesophageal sphincter closed Gastroesophageal sphincter opens Stomach 7/16/2015 5 MDufilho
Figure 23.14a Anatomy of the stomach. Cardia Fundus Esophagus Muscularis externa Longitudinal layer Circular layer Oblique layer Serosa Body Lesser curvature Lumen Rugae of mucosa Greater curvature Duodenum Pyloric sphincter (valve) at pylorus Pyloric canal Pyloric antrum 6
Digestive Processes in the Stomach Physical digestion Denaturation of proteins by HCl Enzymatic digestion of proteins by pepsin (and milk protein by rennin in infants) Lingual lipase digests some triglycerides before digested as any other protein Delivers chyme to small intestine 7
Figure 23.19 Deglutition (swallowing). Slide 1 Pyloric valve closed Pyloric valve closed Pyloric valve slightly opened 1 Propulsion: Peristaltic 2 Grinding: The most 3 Retropulsion: The pyloric waves move from the fundus vigorous peristalsis and end of the stomach acts as a toward the pylorus. mixing action occur close to pump that delivers small amounts the pylorus. of chyme into the duodenum, simultaneously forcing most of its contained material backward into the stomach. 8
Figure 23.1 Alimentary canal and related accessory digestive organs. Mouth (oral cavity) Tongue* Parotid gland Sublingual gland Submandibular gland Salivary glands* Esophagus Liver* Gallbladder* Pharynx Stomach Pancreas* (Spleen) Small intestine Anus Duodenum Jejunum Ileum Transverse colon Descending colon Ascending colon Cecum Sigmoid colon Rectum Appendix Anal canal Large intestine 9
Figure 23.29a Gross anatomy of the large intestine. Right colic (hepatic) flexure Transverse colon Superior mesenteric artery Haustrum Ascending colon IIeum IIeocecal valve Cecum Left colic (splenic) flexure Transverse mesocolon Epiploic appendages Descending colon Cut edge of mesentery Tenia coli Sigmoid colon Appendix Rectum Anal canal External anal sphincter 10
Figure 23.21 The duodenum of the small intestine, and related organs. Right and left hepatic ducts of liver Cystic duct Common hepatic duct Bile duct and sphincter Accessory pancreatic duct Mucosa with folds Gallbladder Major duodenal papilla Hepatopancreatic ampulla and sphincter Duodenum Tail of pancreas Pancreas Jejunum Main pancreatic duct and sphincter Head of pancreas 11
Figure 23.28 Mechanisms promoting secretion and release of bile and pancreatic juice. Slide 1 1 Chyme enter -ing duodenum causes duodenal enteroendocrine cells to release cholecystokinin (CCK) and secretin. 2 CCK (red dots) and secretin (yellow dots) enter the bloodstream. 3 CCK induces secretion of enzyme-rich pancreatic juice. Secretin causes secretion of HCO 3 -rich pancreatic juice. 4 Bile salts and, to a lesser extent, secretin transported via bloodstream stimulate Liver to produce bile more rapidly. 5 CCK (via blood stream) causes gallbladder to contract and Hepatopancreatic Sphincter to relax. Bile Enters duodenum. 6 During cephalic and gastric phases, vagal Nerve stimulates gallbladder to contract weakly. CCK secretion Secretin secretion 7/16/2015 12 MDufilho