PowerPoint ® Lecture Slides prepared by Leslie Hendon, University of Alabama, Birmingham HUMAN ANATOMY fifth edition MARIEB | MALLATT | WILHELM 22 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Digestive System PART 3

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Large Intestine  Digested residue contains few nutrients  Small amount of digestion by bacteria  Main functions  Absorb water and electrolytes  Mass peristaltic movements force feces toward the rectum

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Gross Anatomy of Large Intestine  Subdivided into  Cecum, vermiform appendix, colon, rectum, anal canal  Special features of large intestine  Teniae coli  Thickening of longitudinal muscularis  Haustra  Puckering created by teniae coli  Epiploic appendages  Fat-filled pouches of visceral peritoneum

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Gross Anatomy of Large Intestine  Cecum  Blind pouch  Beginning of large intestine  Vermiform appendix  Contains lymphoid tissue  Neutralizes pathogens  Colon  Divided into distinct segments  Ascending, transverse, descending, and sigmoid colon

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Gross Anatomy of Large Intestine  Rectum  Descends along the inferior half of the sacrum  Anal Canal  The last subdivision of the large intestine  Lined with stratified squamous epithelium

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Gross Anatomy of Large Intestine Figure 22.22a

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Gross Anatomy of Large Intestine Figure 22.22b

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Vessels and Nerves of the Large Intestine  First half of large intestine  Arterial supply - superior mesenteric artery  Innervation  Sympathetic innervation – superior mesenteric and celiac ganglia  Parasympathetic innervation – vagus nerve

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Vessels and Nerves of the Large Intestine  Distal half of large intestine  Arterial supply - inferior mesenteric artery  Innervation  Sympathetic innervation – inferior mesenteric and hypogastric plexuses  Parasympathetic innervation – pelvic splanchnic nerves

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Defecation Reflex Figure 22.23

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Microscopic Anatomy of Large Intestine  Villi are absent  Contains numerous goblet cells  Intestinal crypts – simple tubular glands  Lined with simple columnar epithelial tissue  Epithelium changes at anal canal  Becomes stratified squamous epithelium

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Mucosa of the Large Intestine Figure 22.24

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Liver  Largest gland in the body  Performs over 500 functions  Digestive function  Bile production  Performs many metabolic functions

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Visceral Surface of the Liver Figure 22.26

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Microscopic Anatomy of the Liver  Hepatocyte – functional cells of the liver  Portal triad composed of  Bile duct tributary  Branch of hepatic portal vein  Branch of hepatic artery  Kupffer cells – destroy bacteria

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Microscopic Anatomy of the Liver  Some functions of hepatocytes  Rough ER manufactures blood proteins  Smooth ER produces bile salts, detoxifies poisons  Peroxisomes detoxify poisons (alcohol)  Golgi apparatus packages secretory products  Mitochondria provide energy for liver processes  Glycosomes store sugar  Great capacity for regeneration

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Microscopic Anatomy of Liver Figure 22.27a, c, d

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Gallbladder  Stores and concentrates bile  Expels bile into duodenum  Bile emulsifies fats  Cholecystokinin – released from enteroendocrine cells in response to fatty chyme

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Gallbladder Figure 22.20