Chapter 17   Digestive System
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Chapter 17 Digestive System

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Hole's Anatomy and Physiology II

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Chapter 17   Digestive System Chapter 17 Digestive System Presentation Transcript

  • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 17 Lecture PowerPoint
  • 2402 Anatomy and Physiology II Chapter 17 Susan Gossett [email_address] Department of Biology Paris Junior College
  • Hole’s Human Anatomy and Physiology Twelfth Edition Shier  Butler  Lewis Chapter 17 Digestive System Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. View slide
  • 17.1: Introduction
    • Digestion is the mechanical and chemical breakdown of foods into forms that cell membranes can absorb
    • Organs of the digestive system carry out these processes, as well as ingestion, propulsion, absorption and defecation
    • The digestive system consists of the alimentary canal extending from the mouth to the anus, plus accessory organs that empty into the alimentary canal
    View slide
  • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Anus ACCESSORY ORGANS Salivary glands Secrete saliva, which contains enzymes that initiate breakdown of carbohydrates Liver Produces bile, which emulsifies fat Gallbladder Stores bile and introduces it into small intestine Pancreas Produces and secretes pancreatic juice, containing digestive enzymes and bicarbonate ions, into small intestine ALIMENTARY CANAL Mouth Mechanical breakdown of food; begins chemical digestion of carbohydrates Pharynx Connects mouth with esophagus Esophagus Peristalsis pushes food to stomach Stomach Secretes acid and enzymes; mixes food with secretions to begin enzymatic digestion of proteins Small intestine Mixes food with bile and pancreatic juice; final enzymatic breakdown of food molecules; main site of nutrient absorption Large intestine Absorbs water and electrolytes to form feces Rectum Regulates elimination of feces
  • 17.2: General Characteristics of the Alimentary Canal
    • The alimentary canal is a muscular tube about 8 meters long
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. .5 meter (from tongue to duodenum) 5.5 – 6.0 meters (small intestine) 1.5 meters (large intestine) Esophagus Stomach Gallbladder Pancreas Duodenum Cecum Appendix Anus Tongue Large intestine Ileum (3.3 – 3.6 m) Jejunum (2.2 – 2.4 m) 1.0m
  • Structure of the Wall Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Intestinal gland Lacteal Epithelium Mucous gland in submucosa Mucosa Circular muscle Longitudinal muscle Circular muscle Longitudinal muscle Serosa Artery Mesentery Circular fold Mucosa Submucosa Serosa Capillaries Lacteal Microvilli Nucleus Goblet cell Vein Villi Lymph nodule Nerve plexuses Muscular layer Simple columnar epithelium
  • Movements of the Tube Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. (c) (a) Movement of contents (b) Digesting material Wave of contraction
  • Innervation of the Tube
    • Branches of the sympathetic and parasympathetic divisions of the autonomic nervous system extensively innervate the alimentary canal, including:
      • Submucosal plexus – controls secretions
      • My enteric plexus – controls gastrointestinal motility
    • Remember:
      • Parasympathetic impulses – increase activities of digestive system
      • Sympathetic impulses – inhibit certain digestive actions
  • 17.3: Mouth
    • The mouth:
      • Ingests food
      • Mechanically breaks up solid particles using saliva
      • Prepares food for chemical digestion
    • This action is called mastication
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Uvula Soft palate Hard palate Lip Lip Lingual frenulum Palatine tonsils Tongue Vestibule
  • Cheeks and Lips
    • The cheeks form the lateral walls of the mouth
    • The lips are highly mobile structures that surround the mouth opening
  • Tongue
    • The tongue is a thick, muscular organ that occupies the floor of the mouth and nearly fills the oral cavity when the mouth is closed
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Root Body Epiglottis Lingual tonsils Palatine tonsil Papillae
  • Palate
    • The palate forms the roof of the oral cavity and consists of a hard anterior part and a soft posterior part
    Frontal sinus Hard palate Hyoid bone Trachea Esophagus Laryngopharynx Epiglottis Lingual tonsil Oropharynx Palatine tonsil Uvula Nasopharynx Soft palate Opening of auditory tube Pharyngeal tonsil Sphenoidal sinus Lip Tooth Larynx Nasal cavity Vestibule Tongue Oral cavity Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  • Teeth
    • The teeth are the hardest structures in the body
    • There are primary (deciduous) teeth numbering 20
    • There are secondary (permanent) teeth numbering 32
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © The McGraw-Hill Companies, Inc./Rebecca Gray, photographer
  • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. b: © Nick Koudis/Getty Images Incisors Canine (cuspid) Canine (cuspid) Molars Incisors (a) Molars (b) Canines Premolars (bicuspids) Premolars (bicuspids) Second premolars First premolars Lateral incisors Central incisors
  • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Crown Gingiva Root canal Cementum Root Dentin Enamel Alveolar process Periodontal ligament Pulp cavity
  • 17.1 Clinical Application Dental Caries
  • 17.4: Salivary Glands
    • Salivary glands secrete saliva
    • This begins the digestion of carbohydrates
    • There are three pairs of major salivary glands, including:
      • Parotid glands
      • Submandibular glands
      • Sublingual glands
    • There are many minor glands scattered throughout the mucosa of the tongue, palate, and cheeks
  • Salivary Secretions
    • The different salivary glands have varying proportions of two types of secretory cells, serous cells and mucous cells
      • Serous cells produce a watery fluid with a digestive enzyme called salivary amylase
      • Mucous cells secrete mucous
    • Parotid glands
      • Secrete clear watery, serous fluid
      • Rich in salivary amylase
    • Submandibular glands
      • Secrete primarily serous fluid and some mucus
    • Sublingual glands
      • Secrete primarily mucus
  • Major Salivary Glands Sublingual gland Mandible (cut) Parotid gland Masseter muscle Submandibular gland Tongue Submandibular duct Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Duct (a) Serous cell Duct Mucous cell (c) Serous cell Duct (b) Serous cell Mucous cell a: © The McGraw-Hill Companies, Inc./Al Telser, photographer; figure b: © Biophoto Associates/Photo Researchers, Inc.; figure c: © The McGraw-Hill Companies, Inc./Al Telser, photographer Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  • 17.5: Pharynx and Esophagus
    • The pharynx is a cavity posterior to the mouth from which the tubular esophagus leads to the stomach
    • Both the pharynx and esophagus muscular walls function in swallowing
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mandible Skull Tongue Epiglottis Larynx Esophagus Superior constrictor muscles Middle constrictor muscles Inferior constrictor muscles
  • Structure of the Pharynx
    • The pharynx can be divided into the following parts:
      • Nasopharynx
      • Oropharynx
      • Laryngopharynx
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Superior Middle Inferior Tongue Epiglottis Trachea Nasopharynx with mucosa removed to show muscles Pharyngeal constrictor muscles: (a) The tongue forces food into the pharynx. Food mass Hard palate
  • Swallowing Mechanism
    • Swallowing can be divided into three stages:
      • Voluntary stage where saliva is mixed with chewed food
      • Swallowing begins and the swallowing reflex is triggered
      • Peristalsis transports food in the esophagus to the stomach
    • Specifically:
      • The palate and uvula raise
      • The hyoid bone and larynx elevate
      • The epiglottis closes off top of the trachea
      • The longitudinal muscles of pharynx contract
      • The inferior constrictor muscles relax and the esophagus opens
      • The peristaltic waves pushes food through the pharynx
  • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Superior Middle Inferior Tongue Epiglottis Trachea Esophagus Soft palate Larynx Epiglottis Hyoid bone Esophagus Larynx Tongue Peristaltic wave Stomach Esophagus Food mass Nasopharynx with mucosa removed to show muscles Pharyngeal constrictor muscles: Hard palate Food mass (a) The tongue forces food into the pharynx. Soft palate Superior pharyngeal constrictor muscles Food mass (c) Superior constrictor muscles contract and force food into the esophagus. Food mass Inferior pharyngeal constrictor muscles (b) The soft palate, hyoid bone, and larynx are raised, the tongue is pressed against the palate, the epiglottis closes, and the inferior constrictor muscles relax so that the esophagus opens. (d) Peristaltic waves move food through the esophagus to the stomach.
  • Esophagus Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Esophagus Diaphragm Stomach Esophageal hiatus Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mucosa Lumen Submucosa © Ed Reschke Muscular layer
  • 17.6: Stomach
    • The stomach is a J-shaped, pouch-like organ, about 25-30 centimeters long
    • It hangs inferior to the diaphragm in the upper-left portion of the abdominal cavity
    • The stomach has two layers of smooth muscle
      • An inner circular layer
      • An outer longitudinal layer
      • (There may be a third inner layer of oblique fibers.)
  • Parts of the Stomach Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fundus Body Pylorus Pyloric opening Duodenum Cardia Esophagus Esophagus Esophagus (b) (a) Circular fibers Longitudinal fibers Oblique fibers Longitudinal fibers Pyloric sphincter Lesser curvature Lower esophageal sphincter Pyloric canal Pyloric antrum Gastric folds (rugae) Greater curvature
  • Parts of the Stomach Pyloric sphincter Duodenum Pylorus Fundus Gastric folds Body © Dr. Kent M. Van De Graaff Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  • Gastric Secretions
    • The mucous membrane of the stomach has tubular gastric glands that secrete:
      • Pepsinogen
        • From the chief cells
        • Inactive form of pepsin
      • Pepsin
        • From pepsinogen in the presence of hydrochloric acid
        • Is a protein splitting enzyme
      • Hydrochloric acid
        • From the parietal cells
        • Needed to convert pepsinogen to pepsin
      • Mucus
        • From the goblet cells and the mucous glands
        • Protective to stomach wall
      • Intrinsic factor
        • From the parietal cells
        • Is required for vitamin B 12 absorption
  • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Gastric pits Chief cell (a) (b) Parietal cell Gastric gland Mucous cell Mucosa Submucosa Serosa Mucous cell Gastric pit Parietal cell Chief cell Portion of a gastric gland Portion of a gastric gland Muscle layers b: © The McGraw-Hill Companies, Inc./Al Telser, photographer
  • Regulation of Gastric Secretions Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1 2 3 4 Stimulation Bloodstream Release into bloodstream Parasympathetic preganglionic nerve fiber (in vagus nerve) Gastrin stimulates gastric glands to release more gastric juice Parasympathetic postganglionic impulses stimulate the release of gastric juice from gastric glands Impulses stimulate the release of gastrin
  • Gastric Absorption
    • Gastric enzymes begin breaking down proteins, but the stomach is not well-adapted to absorb digestive products
      • Why not ???
    • The stomach does absorb:
      • Some water
      • Certain salts
      • Certain lipid-soluble drugs
      • Alcohol
  • Mixing and Emptying Actions Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Stomach Chyme Duodenum (a) (b) (c) Pyloric sphincter relaxed Pyloric sphincter contracted Food entering
  • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. From CNS 4 1 2 3 Nerve impulses inhibit peristalsis in stomach wall Duodenum fills with chyme Sensory stretch receptors are stimulated Sensory nerve impulses travel to central nervous system To CNS Vagus nerve
  • 17.2 Clinical Application Oh, My Aching Stomach!
  • 17.7: Pancreas
    • The pancreas has a dual function as both an endocrine gland and exocrine gland
    • The exocrine function is to secrete digestive juice called pancreatic juice
  • Structure of the Pancreas Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Right hepatic duct Left hepatic duct Cystic duct Common hepatic duct Bile duct Bile duct Gallbladder Sphincter muscles Head of pancreas Duodenum Major duodenal papilla Intestinal lumen Pancreatic duct Pyloric sphincter Minor duodenal papilla Major duodenal papilla Tail of pancreas Pancreatic duct Hepatopancreatic sphincter Hepatopancreatic ampulla
  • Pancreatic Juice
    • Pancreatic juice contains enzymes that digest carbohydrates, fats, proteins, and nucleic acids, and include:
      • Pancreatic amylase – splits glycogen into disaccharides
      • Pancreatic lipase – breaks down triglycerides
      • Trypsinogen, chymotrypsinogen, and carboxypeptidase
        • Digest proteins
      • Nucleases – digest nucleic acids
      • Bicarbonate ions – make pancreatic juice alkaline
  • Regulation of Pancreatic Secretion Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Bloodstream 1 5 4 3 2 Stimulation of effector organ Acidic chyme enters duodenum Bicarbonate ions neutralize acidic chyme Intestinal mucosa releases secretin into bloodstream Secretin stimulates pancreas to secrete bicarbonate ions Hormonal signals released into bloodstream Pancreatic juice rich in bicarbonate ions passes down pancreatic ducts to the duodenum
  • 17.8: Liver
    • The liver is the largest internal organ
    • It is located in the upper-right abdominal quadrant just beneath the diaphragm
  • Liver Structure Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Right lobe Coronary ligament Inferior vena cava Left lobe Inferior vena cava Right lobe Gallbladder Quadrate lobe Cystic duct Left lobe Hepatic duct Hepatic artery Bile duct Caudate lobe Gallbladder (b) (a) Round ligament Hepatic portal vein Falciform ligament
  • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Bile duct Branch of hepatic artery Plates of liver cells Central vein Bile canaliculi Bile ductule Bile duct Sinusoids (b) (a) (c) Branch of hepatic portal vein Hepatic sinusoids Branches of hepatic artery Branch of hepatic portal vein c: © The McGraw-Hill Companies, Inc./Al Telser, photographer
  • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Bile duct Bile ductule Bile canaliculi Kupffer cell Hepatic cells Branch of hepatic portal vein Branch of hepatic artery Hepatic sinusoids Blood flow into liver Central vein (blood flow out of liver)
  • Liver Functions
    • The liver carries on many important metabolic activities, including:
      • Produces glycogen from glucose
      • Breaks down glycogen into glucose
      • Converts non-carbohydrates to glucose
      • Oxidizes fatty acids
      • Synthesizes lipoproteins, phospholipids, and cholesterol
      • Converts carbohydrates and proteins into fats
      • Deaminating amino acids
      • Forms urea
      • Synthesizes plasma proteins
      • Converts some amino acids to other amino acids
      • Stores glycogen, iron, and vitamins A, D, and B 12
      • Phagocytosis of worn out RBCs and foreign substances
      • Removes toxins such as alcohol and certain drugs from the blood
  • 17.1 From Science to Technology Replacing the Liver
  • Composition of Bile
    • Bile is a yellowish-green liquid that hepatic cells continuously secrete
    • Bile contains:
      • Water
      • Bile salts:
        • Emulsify fats
        • Help absorb fatty acids, cholesterol, and fat-soluble vitamins
      • Bile pigments
      • Cholesterol
      • Electrolytes
  • 17.3 Clinical Application Hepatitis
  • Gallbladder Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Carroll Weiss/Camera M.D. Studios
  • Regulation of Bile Release Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1 4 5 Gallbladder Bile duct Cystic duct Duodenum 3 Bloodstream 2 Chyme with fat enters duodenum Cells from the intestinal mucosa secrete the hormone cholecystokinin (CCK) into the bloodstream Hormonal signals released into bloodstream Stimulation of effector organ Pancreatic duct Hepatopancreatic sphincter relaxes and bile enters duodenum Bile passes down the cystic duct and bile duct to duodenum CCK stimulates muscular layer of gallbladder wall to contract Common hepatic duct
  • Functions of Bile Salts
    • Bile salts aid digestive enzymes
    • They reduce surface tension and break fat globules into droplets (like soap or detergent) and this is called emulsification
    • They enhance absorption of fatty acids and cholesterol
    • They help absorb fat-soluble vitamins A, D, E and K
    • Bile salts are recycled as they return to the liver
  • 17.4 Clinical Application Gallbladder Disease
  • 17.9: Small Intestine
    • The small intestine is a tubular organ that extends from the pyloric sphincter to the beginning of the large intestine
    • It completes digestion of the nutrients in chyme, absorbs products of digestion, and transports the remaining residue to the large intestine
    • It consists of three parts that include:
      • Duodenum
      • Jejunum
      • Ileum
  • Parts of the Small Intestine Stomach Jejunum Duodenum Ascending colon Mesentery Appendix Cecum Ileum Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Stomach Small intestine © Armed Forces Institute of Pathology
  • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Liver Stomach Gallbladder Transverse colon underneath Greater omentum
  • Structure of the Small Intestinal Wall Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Lacteal Blood capillary network Intestinal gland Goblet cells Simple columnar epithelium Venule Arteriole Lymph vessel Villus Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Lumen Intestinal gland Villus © The McGraw-Hill Companies, Inc./Al Telser, photographer
  • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Microvilli Cell membrane Mitochondrion Golgi apparatus Nucleolus Nucleus (a) Lumen Microvilli (b) Rough endoplasmic reticulum Cytoplasm of epithelial cell b: © The McGraw-Hill Companies, Inc./Al Telser, photographer
  • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Submucosa Circular muscle Longitudinal muscle Serosa (a) (b) Plicae circulares Muscular layer Villi
  • Secretions of the Small Intestine
    • In addition to mucous-secreting goblet cells, there are many specialized mucous-secreting glands (Brunner’s glands) that secrete a thick, alkaline mucus in response to certain stimuli
    • Enzymes in the membranes of the microvilli include:
      • Peptidase – breaks down peptides into amino acids
      • Sucrase , maltase , lactase – break down disaccharides into monosaccharides
      • Lipase – breaks down fats into fatty acids and glycerol
      • Enterokinase – converts trypsinogen to trypsin
      • Somatostatin – hormone that inhibits acid secretion by stomach
      • Cholecystokinin – hormone that inhibits gastric glands, stimulates pancreas to release enzymes in pancreatic juice, and stimulates the gallbladder to release bile
      • Secretin – stimulates the pancreas to release bicarbonate ions in pancreatic juice
  • Regulation of Small Intestinal Secretions
    • Regulation of small intestine secretion occurs by:
      • Mucus secretion is stimulated by the presence of chyme in the small intestine
      • Distension of the intestinal wall activates nerve plexuses in the wall of the small intestine
      • Parasympathetic reflexes triggering the release of intestinal enzymes
  • Absorption of the Small Intestine
    • Villi increase the surface area for absorption
    • Small intestine absorption is so effective that very little reaches the organ’s distal end, noting that:
      • Monosaccharides and amino acids absorb:
        • Through facilitated diffusion and active transport
        • Absorbed into blood
      • Large proteins are broken down and absorbed into villi
      • Fatty acids and glycerol absorb by:
        • Several steps involved as noted
        • Absorbed into lymph and blood
      • Electrolytes and water absorb:
        • Through diffusion, osmosis, and active transport
        • Absorbed into blood
  • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Maltose Glucose Monosaccharides Disaccharide Glucose  H H O Maltase Maltase  HO H O OH OH H O H H HO H O OH HO H O H 2 O Water H N C H H Amino acid Amino acid Dipeptidase   R C H N O C R H H N C H H R C OH O H N C H H R C OH O C OH O Dipeptidase H 2 O Dipeptide (from protein digestion) Water Lipase H C HO HO HO H C H H C H C C 17 H 35 COO H H C H 3H 2 O Lipase + + Fatty acids Glycerol Fat C H C H O C O C O C 17 H 35 COO C 17 H 35 COO Water C 17 H 35 C C 17 H 35 C C 17 H 35 C OH OH OH
  • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fatty acids Lacteal Nucleus Chylomicrons 1 2 3 4 5 Lymph To blood Lymph in lacteal transports chylomicrons away from intestine Chylomicrons leave epithelial cell and enter lacteal Fats collect in clusters encased in protein to form chylomicrons Fatty acids are used to synthesize fats in endoplasmic reticulum Fatty acids resulting from fat digestion enter epithelial cell Endoplasmic reticulum Lumen of intestine Epithelial cell
  • Movements of the Small Intestine
    • The small intestine carries on mixing movements that include:
      • Peristalsis – pushing movements that propel chyme
      • Segmentation – ring-like contractions that can move chyme back and forth
  • 17.10: Large Intestine
    • The large intestine is named because of its diameter
    • It has five parts that include:
      • Cecum
      • Colon
        • Ascending, transverse, descending and sigmoid
      • Rectum
      • Anus
  • Parts of the Large Intestine Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Anal canal Sigmoid colon Haustra Descending colon Rectum Appendix Cecum Orifice of appendix Ileocecal sphincter Ascending colon Serous layer Mucous membrane Transverse colon Muscular layer Ileum Hepatic flexure Tenia coli Splenic flexure Epiploic appendage
  • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Jim Wehtje/Getty Images
  • Structure of the Large Intestinal Wall © Ed Reschke/Peter Arnold Lumen Submucosa Muscular layer Serosa Mucosa Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  • Functions of the Large Intestine
    • The large intestine:
      • Has little or no digestive function
      • Absorbs water and electrolytes
      • Secretes mucus
      • Houses intestinal flora
      • Forms feces
      • Carries out defecation
    Lumen of large intestine Goblet cells © Ed Reschke Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  • Movements of the Large Intestine
    • Movements of the large intestine are similar to those of the small intestine
    • It is slower and less frequent than that of the small intestine
    • Movements include:
      • Mixing movements
      • Peristalsis
    • Mass movements usually follow meals
    • The defecation reflex relaxes the internal anal sphincter and then the external anal sphincter
  • Feces
    • Feces is composed of materials not digested or absorbed, and include:
      • Water
      • Electrolytes
      • Mucus
      • Bacteria
      • Bile pigments altered by bacteria provide the color
    • The pungent odor is produced by bacterial compounds including:
      • Phenol
      • Hydrogen sulfide
      • Indole
      • Skatole
      • Ammonia
  • 17.5 Clinical Application Disorders of the Large Intestine
  • 17.11: Lifespan Changes
    • Changes to the digestive system are slow and slight, and eventually include:
      • Teeth may become sensitive
      • Gums may recede
      • Teeth may loosen, break or fall out
      • Heartburn may become more frequent
      • Constipation may become more frequent
      • Nutrient absorption decreases
      • Accessory organs age but typically not necessarily in ways that effect health
  • Important Points in Chapter 17: Outcomes to be Assessed
    • 17.1: Introduction
    • Describe the general functions of the digestive system.
    • Name the major organs of the digestive system.
    • 17.2: General Characteristics of the Alimentary Canal
    • Describe the structure of the wall of the alimentary canal.
    • Explain how the contents of the alimentary canal are mixed and moved.
    • 17.3: Mouth
    • Describe the functions of the structures of the mouth.
    • Describe how different types of teeth are adapted for different functions, and list the parts of the tooth.
  • Important Points in Chapter 17: Outcomes to be Assessed
    • 17.4-17.10: Salivary Glands – Large Intestine
    • Locate each of the organs and glands; then describe the general function of each.
    • Identify the function of each enzyme secreted by the digestive organs and glands.
    • Describe how digestive secretions are regulated.
    • Explain control of movement of material through the alimentary canal.
    • Describe the mechanisms of swallowing, vomiting, and defecating.
    • Explain how the products of digestion are absorbed.
  • Important Points in Chapter 17: Outcomes to be Assessed
    • 17.11: Lifespan Changes
    • Describe aging-related changes in the digestive system.
  • Quiz 17 Complete Quiz 17 now! Read Chapter 18.