Seeley's Essentials Of Anatomy & Physiology Tenth Edition PDF

Seeley’s ESSENTIALS OF...

Seeley’s ESSENTIALS OF Anatomy & Physiology Tenth Edition Cinnamon Vanputte Jennifer Regan Andrew Russo See separate PowerPoint slides for all figures and tables pre-inserted into PowerPoint without notes. © 2019 McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  2 Week 6 Digestive System Lecture Outline © 2019 McGraw-Hill Education  3 Digestion and the Digestive System Digestion is the breakdown of large organic molecules into smaller molecules that can be absorbed. The digestive system performs the task of digestion. Food is taken into the digestive system, where it is enzymatically broken down into smaller and smaller particles for absorption. © 2019 McGraw-Hill Education  4 Digestive System Functions 1. Ingestion of solids and liquids 2. Digestion of organic molecules (proteins, fats & carbohydrates) 3. Absorption of nutrients 4. Elimination of waste © 2019 McGraw-Hill Education  5 Digestive System 1 Figure © 2019 McGraw-Hill Education 16.1  6 Digestive System 2 The digestive system consists of the digestive tract, plus specific associated organs. The digestive tract is also referred to as the GI (gastrointestinal tract) The tract is one long tube from the mouth to the anus. © 2019 McGraw-Hill Education  Digestive Tract Components 7 The digestive tract consists of the: oral cavity (mouth)- the beginning of digestion Pharynx- It transfer food to the esophagus Esophagus- receives that food Stomach-muscular organ small intestines- the primary site of nutrients absorption large intestines-absorbs water and electrolytes Rectum-stores feces © 2019 McGraw-Hill Education  Associated Organs 8 The digestive system includes some associated organs not directly in the digestive tract, but have ducts that lead into the tract. These associated organs are the: Salivary glands- helps moisten food and starts breaking it down. Liver- makes a substance called bile, which helps break down fats. Gallbladder- stores bile from the liver and releases it into the small intestine when you eat fatty foods. Pancreas- makes digestive enzymes and sends © 2019 McGraw-Hill Education  9 Layers of Digestive Tract Wall 1 The layers of the tract wall are also termed tunics. 1. Mucosa: innermost layer secretes mucus 2. Submucosa: above mucosa contains blood vessels, nerves, small glands © 2019 McGraw-Hill Education  10 Layers of Digestive Tract Wall 2 3. Muscularis: above submucosa longitudinal, circular, and oblique muscles 4. Serosa/adventitia: outermost layer peritoneum is present called serosa no peritoneum then called adventitia © 2019 McGraw-Hill Education  11 Digestive Tract Histology Figure © 2019 McGraw-Hill Education 16.2  12 Peritoneum Layer of smooth epithelial tissue Mesenteries: connective tissue of organs in abdominal cavity (intestines). They also provide a path for blood vessels, nerves, and lymphatics to reach these organs. Lesser omentum: mesentery connecting lesser curvature of stomach to liver and diaphragm Greater omentum: mesentery connecting greater curvature of stomach to transverse colon and posterior body wall © 2019 McGraw-Hill Education  13 Peritoneum and Mesenteries Figure © 2019 McGraw-Hill Education 16.3  14 Oral Cavity 1 First part of digestive system. Salivary glands: produce saliva which contains special proteins called enzymes to breakdown carbohydrates into glucose. cleanse mouth dissolve and moisten food © 2019 McGraw-Hill Education  15 Oral Cavity 2 Amylase: salivary enzyme that breaks down carbohydrates Lysozyme: salivary enzymes that are active against bacteria It is like a natural defense system in our saliva that targets and destroys harmful bacteria. Tongue: © 2019 McGraw-Hill Education  16 Oral Cavity 3 Figure © 2019 McGraw-Hill Education 16.4  17 Teeth 1 32 teeth in normal adult Incisors (8), canine(4), premolars(8), molars(12), wisdom(last to generate) 20 primary teeth (baby teeth) Each tooth has crown, cusp, neck, root Center of tooth is pulp cavity Enamel is hard covering protects against abrasions Cavities are breakdown of enamel by acids from bacteria © 2019 McGraw-Hill Education  18 Teeth 2 Figure © 2019 McGraw-Hill Education 16.5  Molar Tooth in Place in the 19 Alveolar Bone Figure © 2019 McGraw-Hill Education 16.6  20 Palate Palate: roof of oral cavity Hard palate: anterior part Soft palate: posterior part © 2019 McGraw-Hill Education  21 Salivary Glands 1 Salivary Glands: includes submandibular, sublingual, parotid produce saliva contains enzymes to breakdown food mumps is inflammation of parotid gland © 2019 McGraw-Hill Education  22 Salivary Glands 2 Figure © 2019 McGraw-Hill Education 16.7  Pharynx 23 Throat Connects the mouth to the esophagus. It has three parts: Nasopharynx-nasopharynx serves as an airway in the respiratory system Oropharynx-. It plays a crucial role in swallowing, as the muscles of the oropharynx contract to push the food bolus from the mouth into the laryngopharynx. Laryngopharynx- it directs food and liquids into the esophagus © 2019 McGraw-Hill Education  24 Esophagus Tube that connects the pharynx to the stomach Transports food to the stomach Joins stomach at cardiac opening Heartburn: occurs when gastric juices regurgitate into esophagus caused by caffeine, smoking, or eating or drinking in excess © 2019 McGraw-Hill Education  25 Swallowing Voluntary phase: bolus (mass of food) formed in mouth and pushed into oropharynx Pharyngeal phase: swallowing reflex initiated when bolus stimulates receptors in oropharynx Esophageal phase: moves food from pharynx to stomach Peristalsis: wave-like contractions moves food through digestive tract © 2019 McGraw-Hill Education  Events During the Three Phases 26 of Swallowing Figure © 2019 McGraw-Hill Education 16.8  27 Peristalsis Figure © 2019 McGraw-Hill Education 16.9  28 Stomach 1 Located in abdomen Acts as a storage tank for food Can hold up to 2 liters of food Produces mucus, hydrochloric acid, protein digesting enzymes Contains a thick mucus layer that lubricates and protects epithelial cells on stomach wall form acidic pH (3) © 2019 McGraw-Hill Education  29 Stomach 2 3 muscular layers: outer longitudinal, middle circular, and inner oblique to produce churning action Rugae: large folds that allow stomach to stretch Chyme: paste-like substance that forms when food begins to © 2019 McGraw-Hill Education  30 Stomach 3 Pyloric opening: opening between stomach and small intestine Pyloric sphincter: thick, ring of smooth muscle around pyloric opening Hunger pangs: stomach is stimulated to contract by low blood glucose levels usually 12-24 hours © 2019 McGraw-Hill Education  31 Anatomy and Histology of the Stomach Figure © 2019 McGraw-Hill Education 16.10 (c) ©Victor Eroschenko  32 Regulation of Stomach Secretions 1 Cephalic phase: 1st phase (prepares the stomach for food) stomach secretions are initiated by sight, smell, taste, or food thought VAGUS NERVE---PARIETAL CELLS--- GASTRIN © 2019 McGraw-Hill Education  33 Regulation of Stomach Secretions 2 Gastric phase: 2nd phase (Majority of gastric secretion) partially digested proteins and distention of stomach promote secretion HCL © 2019 McGraw-Hill Education  34 Regulation of Stomach Secretions 3 Intestinal phase: 3rd phase(chyme enters the intestines) acidic chyme stimulates neuronal reflexes and secretions of hormones that inhibit gastric secretions. Secretin-slowdown gastric emptying © 2019 McGraw-Hill Education  35 Movement in Stomach 1 Mixing waves: weak contraction in the stomach thoroughly mix food to form chyme Peristaltic waves: stronger contraction force chyme toward and through pyloric sphincter Stomach empties every 4 hours after regular meal, and 6 to 8 hours after high fatty meal © 2019 McGraw-Hill Education  36 Small Intestine 1 Measures 6 meters in length Major absorptive organ Chyme takes 3 to 5 hours to pass through Contains enzymes to further breakdown food Contains secretions for protection against the acidity of chyme © 2019 McGraw-Hill Education  37 Parts of Small Intestine 1 Duodenum: first part (where the food from the stomach enters the S.I) 25 cm long contains absorptive cells, goblet cells, granular cells, endocrine cells contains microvilli and many folds (for more efficient nutrient absorption). contains bile and pancreatic ducts (ducts release bile (from the liver) and enzymes (from the pancreas) to help digest fats and proteins, respectively) © 2019 McGraw-Hill Education  38 Parts of Small Intestine 2 Jejunum: second part 2.5 meters long and absorbs nutrients Ileum: third part 3.5 meters long © 2019 McGraw-Hill Education  39 Small Intestine 2 Figure © 2019 McGraw-Hill Education 16.13  40 Mucosa of the Small Intestine 1 The mucosa of the small intestine is simple columnar epithelium with four major cell types. 1. Absorptive cells, which have microvilli, produce digestive enzymes, and absorb digested food 2. Goblet cells, which produce a protective mucus 3. Granular cells, which may help protect the intestinal epithelium from bacteria; © 2019 McGraw-Hill Education  Segmental Contractions in 41 the Small Intestine Figure © 2019 McGraw-Hill Education 16.15  42 Liver Anatomy 1 Weighs about 3 lbs. Located in the right upper quadrant of the abdomen under the diaphragm Consists of right, left, caudate, and quadrate lobes Porta: gate where blood vessels, ducts, nerves enter and exit Receives arterial blood from the hepatic artery © 2019 McGraw-Hill Education  43 Liver Figure © 2019 McGraw-Hill Education 16.16  44 Liver Anatomy 2 Lobules: divisions of liver with portal triads at corners Portal triad: contain hepatic artery, hepatic portal vein, hepatic duct Hepatic cords: between center margins of each lobule separated by hepatic sinusoids © 2019 McGraw-Hill Education  45 Liver Anatomy 3 Hepatic sinusoids: contain phagocytic cells that remove foreign particles from blood Central vein: center of each lobule where mixed blood flows towards forms hepatic veins © 2019 McGraw-Hill Education  46 Liver Ducts Hepatic duct: transport bile out of liver Common hepatic duct: formed from left and right hepatic duct Cystic duct: joins common hepatic duct from gallbladder Common bile duct: formed from common hepatic duct and cystic duct © 2019 McGraw-Hill Education  47 Bile and Pancreatic Secretions Figure © 2019 McGraw-Hill Education 16.17  48 Functions of the Liver Digestive and excretory functions Stores and processes nutrients Detoxifies harmful chemicals Synthesizes new molecules Secretes 700 milliliters of bile each day Bile: dilutes and neutralizes stomach acid and breaks down fats © 2019 McGraw-Hill Education  49 Control of Bile Secretion and Release Figure © 2019 McGraw-Hill Education 16.18  50 Pancreas 1 Located posterior to stomach in inferior part of left upper quadrant Head near midline of body Tail extends to left and touches spleen Endocrine tissues have pancreatic islets that produce insulin and glucagon Exocrine tissues produce digestive enzymes that travel through ducts © 2019 McGraw-Hill Education  51 Pancreatic Secretions 2 The major protein-digesting enzymes are: 1. Trypsin (breaks down large proteins into smaller peptide chains) 2. Chymotrypsin (breaks down proteins into smaller peptide fragments, but it targets different amino acids compared to trypsin) 3. Carboxypeptidase (breaks off individual amino acids from the © 2019 McGraw-Hill Education  52 Duodenum and Pancreas Figure © 2019 McGraw-Hill Education 16.19  53 Large Intestine 1 Function is to absorb water from indigestible food Contains cecum, colon, rectum, anal canal Cecum: joins small intestine at ileocecal junction has appendix attached Appendix: 9 cm structure that is often removed © 2019 McGraw-Hill Education  54 Large Intestine 2 Colon: 1.5 meters long contains ascending, transverse, descending, sigmoid regions Rectum: straight tube that begins at sigmoid and ends at anal canal © 2019 McGraw-Hill Education  55 Large Intestine 3 Anal canal: last 2 to 3 cm of dig. tract Food takes 18-24 hours to pass through Feces is product of water, indigestible food, and microbes Microbes synthesize vitamin K © 2019 McGraw-Hill Education  56 Large Intestine Figure © 2019 McGraw-Hill Education 16.21 (b) ©CNRI/SPL/Science Source  57 Digestive Process 1 1. Digestion: breakdown of food occurs in stomach and mouth 2. Propulsion: moves food through digestive tract includes swallowing and peristalsis © 2019 McGraw-Hill Education  58 Digestive Process 2 3. Absorption: primarily in duodenum and jejunum of small intestine 4. Defecation: elimination of waste in the form of feces © 2019 McGraw-Hill Education  59 Digestion Figure © 2019 McGraw-Hill Education 16.22  Carbohydrate, Lipid and Protein 60 Digestion Polysaccharides split into disaccharides by salivary and pancreatic amylases. Lipase breaks down triglycerides into fatty acids and monoglycerides. Pepsin is a protein-digesting enzyme secreted by the stomach. © 2019 McGraw-Hill Education  61 Water and Minerals 99% of water entering intestine is absorbed Minerals are actively transported across wall of small intestine © 2019 McGraw-Hill Education