BIO 139 ANATOMY AND PHYSIOLOGY II THE DIGESTIVE SYSTEM

BIO 139 ANATOMY AND PHYSIOLOGY II THE DIGESTIVE SYSTEM MARY CATHERINE FLATH, Ph.D.

DIGESTIVE SYSTEM ORGANS MOUTH PHARYNX ESOPHAGUS STOMACH SMALL INTESTINE LARGE INTESTINE SALIVARY GLANDS PANCREAS LIVER GALLBALDDER FUNCTION TO BREAKDOWN FOOD INTO SIMPLE NUTRIENTS WHICH CAN BE ABSORBED (PRIMARILY FOR ENERGY) Copyright 2012 Dr. Mary Cat Flath

ORGANIC MOLECULES Macromolecule Carbohydrates Lipids Proteins Nucleic Acids Atoms C, H, O C, H, O (much less O) Monomers Monosaccharides Triglycerides = glycerol and 3 fatty acids Specific Monomer(s) With function Specific Polymer (s) With Function Glucose, Fructose, Galactose Energy 1. Disaccharides: Sucrose, Maltose, Lactose: Energy 2. Polysaccharides: Glycogen (animals) Starch (plants): Energy 1.TG = energy. 2. Phospholipid = cell membrane component. 3. Steroids = cell membranes and chemical messengers. N/A C, H, O, N, S C, H, O, N, P Amino acids Nucleic acids = pentose sugar, phosphate, & base 20 different with same basic structure; differ in R groups or sidechains Proteins with many functions: ENZYMES, antibodies, structural, transport, chemical messengers, storage N/A 1. DNA, Deoxyribonucleic Acid directs protein synthesis. 2. RNA, Ribonucleic Acids assists DNA in protein synthesis Other info Saturated (all single bonds) vs. unsaturated fats (1 or more double bond) Copyright 2012 Dr. Mary Cat Flath

ALIMENTARY CANAL FROM MOUTH TO ANUS CHARACTERISTIC WALL STRUCTURE SPHINCTER MUSCLES BETWEEN ORGANS MOVEMENT OF FOOD BY PERISTALSIS

MOVEMENTS THROUGH THE ALIMENTARY CANAL MIXING PERISTALSIS

INNERVATION OF THE TUBE Autonomic Nervous System Parasympathetic activates digestion Sympathetic slows digestion Postganlionic Networks Submucosal plexus controls secretions Myenteric plexus controls peristalsis Copyright 2012 Dr. Mary Cat Flath

ORGANS OF THE ALIMENTARY CANAL

THE MOUTH SITE OF MECHANICAL DIGESTION; THE FIRST SITE OF CARBOHYDRATE DIGESTON: SALIVARY AMYLASE

Taste Sensations Four Primary Taste Sensations sweet stimulated by carbohydrates Tip of tongue sour stimulated by acids Lateral tongue salty stimulated by salts Perimeter of tongue bitter stimulated by many organic compounds Posterior tongue Spicy foods activate pain receptors Copyright 2012 Dr. Mary Cat Flath 12-22

SALIVARY GLANDS SECRETE SALIVA, A WATERY FLUID CONTAINING SALIVARY AMYLASE INTO FOOD IN MOUTH; SALIVARY AMYLASE CHEMICALLY BREAKS POLYSACCHARIDES (GLYCOGEN AND STARCH) INTO DISACCHARIDES

THE TEETH BEGIN THE MECHANICAL BEAKDOWN OF FOOD

THE PHARYNX The throat: Common passageway for food (digestive system) and air (respiratory system)

DEGLUTITION SWALLOWING

THE ESOPHAGUS CARRIES THE SWALLOWED BOLUS OF FOOD TO THE STOMACH THROUGH PERISTALSIS

THE STOMACH THE FIRST SITE OF CHEMICAL DIGESTION OF PROTEINS THROUGH THE ENZYME PEPSIN, WHICH BREAKS PROTEINS INTO PEPTIDES.

GASTRIC MUCOSA GASTRIC PITS ARE LINED BY GASTRIC GLANDS GASTRIC GLANDS SECRETE GASTRIC JUICE GASTRIN GLANDS ARE COMPOSED OF FOUR TYPES OF CELLS CHIEF CELLS SECRETE THE ENZYME PEPSIN PARIETAL CELLS SECRETE HYDROCHLORIC ACID AND INTRINSIC FACTOR MUCOUS/GOBLET CELLS SECRETE MUCUS G-CELLS SECRETE THE HORMONE Copyright 2012 Dr. Mary Cat Flath GASTRIN

REGULATION OF RELEASE OF GASTRIC JUICE WHEN STOMACH FILLS (STRETCHES) THE HORMONE GASTRIN IS SECRETED BY G- CELLS GASTRIN TARGETS THE GASTRIC GLANDS AND INCREASES THE RELEASE OF GASTRIC JUICE GASTRIN ALSO CAUSES INCREASED MIXING AND OVER TIME CONTRACTS THE GASTROESOPHAGEAL SPHINCTER AND RELAXES THE PYLORIC SPHINCTER Copyright 2012 Dr. Mary Cat Flath

MINIMAL ABSORPTION OCCURS IN STOMACH (5%) ETHANOL, DRUGS, AND SOME VITAMINS ARE ABSORBED

MOVEMENT OF CHYME INTO SMALL INTESTINE AS PERISTALTIC WAVES PUSH GASTRIC CHYME TOWARD PYLORIC SPHINCTER IT RELAXES AND CHYME ENTERS DUODENUM OF SMALL INTESTINE A LITTLE BIT AT A TIME Copyright 2012 Dr. Mary Cat Flath

THE PANCREAS SECRETES PANCREATIC JUICE CONTAINING AMYLASE, PROTEINASES, LIPASES, AND NUCLEASES INTO DUODENUM; THESE ENZYMES BREAK DOWN EACH OF THE MACROMOLECULES WE INGEST & Bicarbonate neutralizes acid

PANCREATIC ENZYMES AMYLASE POLYSACCHARIDES TO DISACCHARIDES LIPASES TRIGLYCERIDES TO MONOGLYCERIDE AND TWO FATTY ACIDS PROTEINASES PROTEINS TO PEPTIDES NUCLEASES NUCLEIC ACIDS TO NUCLEOTIDES Copyright 2012 Dr. Mary Cat Flath

REGULATION OF PANCREATIC SECRETIONS WHEN ACIDIC CHYME ENTERS DUODENUM INTESTINAL MUCOSA SECRETES THE HORMONE SECRETIN INTO BLOODSTREAM SECRETIN TARGETS THE PANCREAS AND STIMULATES THE RELEASE OF PANCRETIC JUICE INTO THE DUODENUM Copyright 2012 Dr. Mary Cat Flath

Let s review objectives 1-36

THE LIVER PRODUCES BILE WHICH EMULSIFIES FATS IN THE DUODENUM

BILE EMULSIFIES FAT INCREASES ITS SURFACE AREA FOR MORE EFFECTIVE DIGESTION BY LIPASES

THE GALLBLADDER STORES BILE (PRODUCED IN LIVER) BETWEEN MEALS; BILE IS DEPOSITED BILE INTO THE DUODENUM

Bile Secretion, Storage, and Flow From Liver Common Hepatic Duct Common Bile Duct Sphincter of Oddi Duodenum From Gallbladder Cystic Duct Common Bile Duct Sphincter of Oddi Duodenum Copyright 2012 Dr. Mary Cat Flath

REGULATION OF BILE RELEASE WHEN FATTY CHYME ENTERS THE DUODENUM, THE INTESTINAL MUCOSA RELEASE THE HORMONE CHOLECYSTOKININ (CCK) INTO THE BLOODSTREAM CCK TARGETS THE GALLBLADDER AND CAUSES IT TO CONTRACT AND RELAXES COMMON BILE DUCT BILE IS DEPOSITED INTO DUODENUM Copyright 2012 Dr. Mary Cat Flath

Let s review objectives 37-48

THE SMALL INTESTINE SITE OF COMPLETION OF DIGESTION (DUODENUM) SUCRASE, MALTASE, LACTASE, PEPTIDASES, LIPASE SITE OF ABSORPTION OF SIMPLE NUTRIENTS (JEJUNUM & ILEUM)

THE SMALL INTESTINE IS SUSPENDED IN THE ABDOMINAL CAVITY BY MESENTERY

INTESTINAL MUCOSA LINING IS SIMPLE COLUMNAR EPITHELIUM WITH GOBLET CELLS AND MICROVILLI INTESTINAL VILLI ARE LINED BY INTESTINAL GLANDS INTESTINAL VILLI HAVE A LACTEAL IN THEIR CORE Copyright 2012 Dr. Mary Cat Flath

LIGHT MICROGRAPHS OF THE SMALL INTESTINE

DIGESTIVE ENZYMES OF INTESTINAL GLANDS IN PEPTIDASES DUODENUM PEPTIDES TO AMINO ACIDS LIPASES TRIGLYCERIDES TO MONOGLYCERIDE AND TWO FATTY ACIDS SUCRASE, MALTASE, AND LACTASE DISACCHAARIDES TO MONOSACCHARIDES Copyright 2012 Dr. Mary Cat Flath

ABSORPTION OF SIMPLE NUTRIENTS DISTAL SMALL INTESTINE JEJUNUM AND ILEUM

THE LARGE INTESTINE SITE OF REABSORPTION OF WATER AND ELECTROLYTES FROM CHYME STORAGE (OF FECES) INTESTINAL FLORA (BACTERIA) DIGEST SUBSTANCES WE CANNOT = GAS

THE DIGESTIVE SYSTEM List the four major organic macromolecules that we ingest, and explain how each is broken down by various enzymes within the alimentary canal. Be sure to include enzyme names, the location of enzyme action, the breakdown products that result from the enzymatic action, and explain any hormonal control of the breakdown. Finally, explain how and where these simplest food forms are absorbed into the bloodstream or lymphatic system. Copyright 2012 Dr. Mary Cat Flath

MOUTH DIGESTION OF CARBOHYDRATES SALIVARY AMYLASE POLYSACCHARIDES TO DISACCHARIDES DUODENUM PANCREATIC AMYLASE POLYSACCHARIDES TO DISACCHARIDES (SECRETIN) DUODENUM LACTASE, SUCRASE, MALTASE DISACCHARIDES TO MONOSACCHARIDES Copyright 2012 Dr. Mary Cat Flath

DIGESTION OF LIPIDS DUODENUM (TRIGLYCERIDES) PANCREATIC LIPASE BILE TO EMULSIFY (CCK) TRIGLYCERIDES TO MONOGLYCERIDES AND FATTY ACIDS (SECRETIN) DUODENUM DUODENAL LIPASE TRIGLYCERIDES TO MONOGLYCERIDES AND FATTY ACIDS Copyright 2012 Dr. Mary Cat Flath

DIGESTION OF PROTEINS STOMACH PEPSIN (HCl; GASTRIN) PROTEINS TO PEPTIDES DUODENUM PANCREATIC PROTEASES PROTEINS TO PEPTIDES (SECRETIN) DUODENUM DUODENAL PEPTIDASES PEPTIDES TO AMINO ACIDS Copyright 2012 Dr. Mary Cat Flath

Short Answer Question for Digestion List the four major organic macromolecules that we ingest, and explain how each is broken down by various enzymes within the alimentary canal. Be sure to include enzyme names, the location of enzyme action, the breakdown products that result from the enzymatic action, and explain any hormonal control of the breakdown. Finally, explain how and where these simplest food forms are absorbed into the bloodstream or lymphatic system. Copyright 2012 Dr. Mary Cat Flath

Site of digestion Digestive Enzymes Macromolecule Start/Endproduct(s) of digestion Mode of Absorption body fluid Hormonal Control

Macromolecule Carbohydrates Lipids Proteins Nucleic Acids Site of digestion 1. Mouth 2. Duodenum 3. Duodenum 1. Duodenum 2. Duodenum 1. Stomach 2. Duodenum 3. Duodenum 1. Duodenum Digestive Enzymes 1. Salivary Amylase 2. Pancreatic Amylase 3. Maltase, Sucrase, Lactase 1. Pancreatic Lipases (bile require) 2. Duodenal Lipases (bile required) 1. Pepsin (HCl required) 2. Pancreatic Proteases 3. Peptidases 1. Pancreatic Nucleases Start/Endproduct(s) of digestion 1. Polysaccharides (PS) to Disaccharides (DS). 2. PS to DS 3. DS to Monosaccharides 1. Triglycerides to Monoglyceride and 2 fatty acids 2. Triglycerides to Monoglyceride and 2 fatty acids 1. Proteins to Peptides 2. Proteins to Peptides 3. Peptides to Amino Acids 1. Nucleic Acids to Nucleotides Mode of Absorption body fluid Facilitated Diffusion (and active transport) into blood in mesenteric vein to Hepatic Portal Vein Simple Diffusion, then recombined into chylomicrons absorbed into lymph in lacteal Active Transport into blood in gastric vein to Hepatic Portal Vein NA Hormonal 2. Secretin 2. Secretin and CCK 1. Gastrin 2. Secretin 1. Secretin

Let s review objectives 48-60 Good luck studying!