Principles of Anatomy and Physiology Thirteenth Edition Gerard J. Tortora • Bryan H. Derrickson Chapter 24 The Digestive System Copyright © 2012 by John Wiley & Sons, Inc.

Mouth (oral cavity) contains teeth and tongue Parotid gland (salivary gland) Sublingual gland (salivary gland) Submandibular gland (salivary gland) Pharynx Esophagus Stomach Liver Pancreas Duodenum Transverse colon Gallbladder Descending colon Jejunum Sigmoid colon Ascending colon Rectum Ileum Anal canal Cecum Anus Appendix (a) Right lateral view of head and neck and anterior view of trunk

SUPERIOR Diaphragm Falciform ligament Stomach Liver Transverse colon Gallbladder Ascending colon Descending colon Cecum Jejunum Ileum (b) Anterior view

Submucosal plexus (plexus of Meissner) Mesentery Duct of gland outside tract (such as pancreas) Gland in mucosa Vein Glands in submucosa Mucosa-associated lymphatic tissue (MALT) Lumen Artery MUCOSA: Nerve Epithelium Myenteric plexus (plexus of Auerbach) Lamina propria Muscularis mucosae SUBMUCOSA MUSCULARIS: SEROSA: Circular muscle Areolar connective tissue Longitudinal muscle Epithelium

(a) Midsagittal section showing the peritoneal folds Diaphragm Liver LESSER OMENTUM Pancreas MESOCOLON Stomach Duodenum MESENTERY Transverse colon GREATER OMENTUM Jejunum Ileum PARIETAL PERITONEUM Sigmoid colon VISCERAL PERITONEUM Uterus PERITONEAL CAVITY Urinary bladder Rectum Pubic symphysis Midsagittal plane POSTERIOR ANTERIOR (a) Midsagittal section showing the peritoneal folds

FALCIFORM LIGAMENT Liver Stomach Transverse colon GREATER OMENTUM Urinary bladder (b) Anterior view

Gallbladder (reflected upward) LESSER OMENTUM Liver (reflected upward) Stomach Duodenum Transverse colon Descending colon Ascending colon Sigmoid colon (c) Lesser omentum, anterior view (liver and gallbladder lifted)

GREATER OMENTUM (reflected upward) Transverse colon Jejunum (pulled laterally) MESENTERY Descending colon Ileum (pulled laterally) Sigmoid colon Urinary bladder (d) Anterior view (greater omentum lifted and small intestine reflected to right side)

SUPERIOR Lungs Heart Diaphragm Right lobe of liver FALCIFORM LIGAMENT Left lobe of liver Stomach GREATER OMENTUM (e) Anterior view

Hard palate Soft palate Uvula Cheek Molars Premolars Cuspid (canine) Superior lip (lifted upward) Superior labial frenulum Gingivae (gums) Palatoglossal arch Hard palate Fauces Soft palate Palatopharyngeal arch Uvula Palatine tonsil (between the arches) Cheek Tongue (lifted upward) Molars Lingual frenulum Premolars Opening of duct of submandibular gland Cuspid (canine) Gingivae (gums) Incisors Oral vestibule Inferior labial frenulum Inferior lip (pulled down) Anterior view

(a) Location of salivary glands Parotid duct Zygomatic arch PAROTID GLAND Opening of parotid duct (near second maxillary molar) Second maxillary molar tooth Tongue (raised in mouth) Lingual frenulum Sublingual ducts Lesser sublingual duct Submandibular duct SUBMANDIBULAR GLAND Mylohyoid muscle SUBLINGUAL GLAND (a) Location of salivary glands

Sagittal section of a mandibular (lower) molar Sagittal plane Enamel Dentin CROWN Gingival sulcus Gingiva (gum) NECK Pulp in pulp cavity Cementum Root canal Alveolar bone ROOT Periodontal ligament Apical foramen Nerve Blood supply Sagittal section of a mandibular (lower) molar

Central incisor(8–12 mo.) Lateral incisor(12–24 mo.) Cuspid or canine (16–24 mo.) E F D G First molar (12–16 mo.) C H Second molar (24–32 mo.) B I A J Upper Teeth Lower Teeth Second molar (24–32 mo.) T K First molar (12–16 mo.) S L R M Cuspid or canine (16–24 mo.) Q P O N Lateral incisor(12–15 mo.) Central incisor(6–8 mo.) (a) Deciduous (primary) dentition; teeth are designated by letters (with times of eruption)

First premolar or bicuspid (9–10 yr.) Central incisor (7–8 yr.) Lateral incisor(8–9 yr.) Cuspid or canine (11–12 yr.) 7 8 9 10 11 6 First premolar or bicuspid (9–10 yr.) 12 5 13 4 Second premolar or bicuspid (10–12 yr.) 3 14 2 15 First molar (6–7 yr.) 1 Upper Teeth 16 Second molar (12–13 yr.) Third molar or wisdom tooth (17–21 yr.) Lower Teeth 32 17 Third molar or wisdom tooth (17–21 yr.) 31 18 Second molar (11–13 yr.) 30 19 First molar (6–7 yr.) 29 20 28 21 Second premolar or bicuspid (11–12 yr.) 27 22 26 23 25 24 First premolar or bicuspid (9–10 yr.) (b) Permanent (secondary) dentition; teeth are designated by numbers (with times of eruption) Cuspid or canine (9–10 yr.) Lateral incisor(7–8 yr.) Central incisor(7–8 yr.)

Muscularis (circular layer) Lumen of esophagus Mucosa: Nonkeratinized stratified squamous epithelium Lamina propria Muscularis mucosae Transverse plane Submucosa Muscularis (circular layer) Muscularis (longitudinal layer) Adventitia 20x LM Wall of the esophagus

(a) Position of structures before swallowing Nasopharynx Hard palate Soft palate Bolus Uvula Tongue Oropharynx Epiglottis Laryngopharynx Larynx Esophagus (a) Position of structures before swallowing (b) During pharyngeal stage of swallowing

(c) Anterior view of frontal sections of peristalsis in esophagus Relaxed muscularis Circular muscles contract Longitudinal muscles contract Lower esophageal sphincter Relaxed muscularis Bolus Stomach (c) Anterior view of frontal sections of peristalsis in esophagus

Esophagus Lower esophageal sphincter FUNDUS Serosa CARDIA Muscularis: Longitudinal layer BODY Circular layer Lesser curvature PYLORUS Oblique layer Greater curvature Duodenum Pyloric sphincter Rugae of mucosa PYLORIC ANTRUM PYLORIC CANAL (a) Anterior view of regions of stomach

(b) Anterior view of internal anatomy Esophagus Duodenum PYLORUS Pyloric sphincter PYLORIC CANAL FUNDUS Lesser curvature CARDIA BODY PYLORIC ANTRUM Rugae of mucosa Greater curvature (b) Anterior view of internal anatomy

(a) Three-dimensional view of layers of stomach Lumen of stomach Gastric pits Surface mucous cell Lamina propria MUCOSA Mucous neck cell Parietal cell Chief cell Gastric gland Lymphatic nodule G cell SUBMUCOSA Muscularis mucosae Lymphatic vessel Venule MUSCULARIS Arteriole Oblique layer of muscle Circular layer of muscle SEROSA Myenteric plexus Longitudinal layer of muscle (a) Three-dimensional view of layers of stomach

Surface mucous cell (secretes mucus) Gastric pit Surface mucous cell (secretes mucus) Surface mucous cells Gastric pit Lamina propria Mucous neck cell (secretes mucus) 40x SEM Stomach mucosa Parietal cell (secretes hydrochloric acid and intrinsic factor) Gastric glands Chief cell (secretes pepsinogen and gastric lipase) Muscularis mucosae G cell (secretes the hormone gastrin) Submucosa (b) Sectional view of stomach mucosa showing gastric glands and cell types

Gastric pit Lamina propria Surface mucous cell Lumen of gastric gland Mucous neck cell Parietal cell G cells Chief cells Lumen of gastric gland LM 180x (c) Fundic mucosa

(a) Anterior view Falciform ligament Diaphragm Right lobe of liver Coronary ligament Left lobe of liver Right hepatic duct Left hepatic duct Gallbladder: Common hepatic duct Neck Round ligament Cystic duct Common bile duct Body Fundus Tail Pancreas Body Duodenum Pancreatic duct (duct of Wirsung) Head Accessory duct (duct of Santorini) Jejunum Hepatopancreatic ampulla (ampulla of Vater) Uncinate process (a) Anterior view

(b) Details of hepatopancreatic ampulla Common bile duct Pancreatic duct (duct of Wirsung) Hepatopancreatic ampulla (ampulla of Vater) Mucosa of duodenum Major duodenal papilla Sphincter of the hepatopancreatic ampulla (sphincter of Oddi) (b) Details of hepatopancreatic ampulla

Right hepatic duct Left hepatic duct Common hepatic duct from liver Cystic duct from gallbladder Common bile duct Pancreatic duct from pancreas Key: Liver Sphincter Gallbladder Pancreas Duodenum (c) Ducts carrying bile from liver and gallbladder and pancreatic juice from pancreas to duodenum

Falciform ligament Liver Diaphragm Hepatic bile duct Spleen Cystic bile duct Tail of pancreas Gallbladder Pancreatic duct (duct of Wirsung) Common bile duct Body of pancreas Major duodenal papilla Head of pancreas Duodenum (d) Anterior view

SUPERIOR MEDIAL LATERAL (e) Anterior view Duodenum Tail of pancreas Common bile duct Body of pancreas Major duodenal papilla Pancreatic duct (duct of Wirsung) Head of pancreas Uncinate process MEDIAL LATERAL (e) Anterior view

Liver Inferior vena cava Hepatic artery Hepatic portal vein Connective tissue Hepatocyte Portal triad: Hepatic laminae Bile duct Branch of hepatic artery Branch of hepatic portal vein Central vein Hepatic sinusoids (a) Overview of histological components of liver

(b) Details of histological components of liver Hepatic sinusoids Bile canaliculi Central vein To hepatic vein Portal triad: Bile duct Branch of hepatic portal vein Branch of hepatic artery Hepatic laminae Hepatocyte Stellate reticuloendothelial (Kupffer) cell Connective tissue Hepatic sinusoid (b) Details of histological components of liver

1 2 3 4 5 6 Nutrient-rich, deoxygenated blood from hepatic portal vein Oxygenated blood from hepatic artery 1 2 Liver sinusoids 3 Central vein 4 Hepatic vein 5 Inferior vena cava 6 Right atrium of heart

Stomach DUODENUM Large intestine JEJUNUM ILEUM (a) Anterior view of external anatomy

Circular folds (plicae circulares) (b) Internal anatomy of jejunum

Circular folds (plicae circulares) Villi Submucosa Circular layer of muscle (a) Relationship of villi to circular folds Longitudinal layer of muscle Serosa

Lumen of small intestine Blood capillary Lacteal Villi Opening of intestinal gland Absorptive cell Goblet cell Lacteal MUCOSA Lamina propria Enteroendocrine cell Paneth cell Lymphatic nodule Muscularis mucosae SUBMUCOSA Arteriole Venule MUSCULARIS Lymphatic vessel Circular layer of muscle Myenteric plexus SEROSA Longitudinal layer of muscle (b) Three-dimensional view of layers of the small intestine showing villi

Microvilli Absorptive cell (absorbs nutrients) Blood capillary Lacteal Goblet cell (secretes mucus) Lamina propria Mucosa Intestinal gland Enteroendocrine cell (secretes the hormones secretin, cholecystokinin, or GIP) Muscularis mucosae Arteriol Venule Submucosa Paneth cell (secretes lysozyme and is capable of phagocytosis) Lymphatic vessel Muscularis (c) Enlarged villus showing lacteal, capillaries, intestinal glands, and cell type

(d) Several microvilli from duodenum Brush border Simple columnar epithelial cell TEM 46,800x (d) Several microvilli from duodenum

(b) Movement of absorbed nutrients into blood and lymph Left subclavian vein Villus (greatly enlarged) Chylomicron Small short-chain fatty acid Heart Blood capillary Liver Hepatic portal vein Amino acid Lacteal Thoracic duct Monosaccharide Arteriole Venule Blood Lymphatic vessel Lymph (b) Movement of absorbed nutrients into blood and lymph

INGESTED AND SECRETED ABSORBED Saliva (1 liter) Ingestion of liquids (2.3 liters) Gastric juice (2 liters) Bile (1 liter) Pancreatic juice (2 liters) Intestinal juice (1 liter) Small intestine (8.3 liters) Total ingested and secreted Large intestine (0.9 liters) = 9.3 liters Total absorbed = 9.2 liters Excreted in feces (0.1 liter) Fluid balance in GI tract

(a) Anterior view of large intestine showing major regions TRANSVERSE COLON Left colic (splenic) flexure Right colic (hepatic) flexure Teniae coli ASCENDING COLON DESCENDING COLON Teniae coli Omental appendices Ileum Mesoappendix Haustra Ileocecal sphincter (valve) SIGMOID COLON CECUM RECTUM VERMIFORM APPENDIX ANAL CANAL ANUS (a) Anterior view of large intestine showing major regions

(b) Frontal section of anal canal Rectum Anal canal Internal anal sphincter (involuntary) External anal sphincter (voluntary) Anus Anal column (b) Frontal section of anal canal

(a) Three-dimensional view of layers of large intestine Lumen of large intestine Openings of intestinal glands Absorptive cell MUCOSA Goblet cell Intestinal gland Lamina propria Lymphatic nodule SUBMUCOSA Muscularis mucosae Lymphatic vessel MUSCULARIS Arteriole Venule Circular layer of muscle Myenteric plexus SEROSA Longitudinal layer of muscle (a) Three-dimensional view of layers of large intestine

(b) Sectional view of intestinal glands and cell types Openings of intestinal glands Lamina propria Microvilli Intestinal gland Absorptive cell (absorbs water) Goblet cell (secretes mucus) Muscularis mucosae Lymphatic nodule Submucosa (b) Sectional view of intestinal glands and cell types