Download - Chapter 18 Digestive System
Chapter 18 Digestive System Digestive System Food must be
converted by physical andchemical changes before it can be used
bythe cells; this process is called digestion Enzymes Alimentary
canal Accessory organs Layers of the Digestive System
Mucosa Innermost lining Submucosa Circular muscle Longitudinal
muscle Lining of the Digestive System
Peritoneum Parietal Visceral Mesentery Greater omentum Peritonitis
Functions of the Digestive System
Break down food physically Change food chemically Absorb the
nutrients Eliminate the waste products of digestion Organs of
Digestion Mouth (oral or buccal cavity)
Tongue/accessory organ of digestion Salivary glands Teeth/Accessory
Organ of Digestion
Gingivae or gums Teeth Food chewed or masticated Deciduous and
permanent teeth Structure of the tooth Esophagus Muscular tube to
transport swallowed food to stomach
Esophageal wall layers Mucosa Submucosa Muscular External serous
Stomach Fundus Body or great curvature Pylorus Upper part
Middle section Pylorus Lower portion Stomach Sphincters Four layers
of the stomach wall Cardiac sphincter
Pyloric sphincter Four layers of the stomach wall Gastric Juices
Enteroendocrine glands Parietal cells Chief type cells
Secrete gastrin Parietal cells Produce HCL and intrinsic factor
Chief type cells Produce pepsinogen Gastric Juices Mucus cells
Rennin Secrete alkaline mucus
Found in infants and children Small Intestine About 20 feet long
Same four layers as the stomach
Duodenum Jejunum Ileum Digestive Juices in the Small
Intestine
Enzymes, secretin, and cholecystokinin Pancreatic juices Bile
Intestinal juices Absorption in the Small Intestine
Villi Makes absorption possible Each villi contains a network of
blood andlymph capillaries Digested portion passes through the
villi intothe bloodstream and lacteals Absorption in the Small
Intestine
Undigested portion passes on to the largeintestine Accessory Organs
of Digestion
Pancreas Liver Gallbladder Large Intestine Also called the colon
About 5 feet long
Ileum empties chyme through ileocecal valve into large intestine
Secretes mucus to lubricate passageway Large Intestine Cecum and
appendix
Ascending, transverse, and descending colon Sigmoid colon Anal
canal Digestive System Structures General Overview of
Digestion
Bolus Peristalsis Digestion of protein, fats, and carbohydrates
Absorption of nutrients Undigested substance - feces General
Overview of Digestion
Action in the mouth Action in the pharynx Action in the esophagus
Action in the stomach Action in the small intestine Action in the
large intestine Action in the Large Intestine
Absorption Bacterial action Gas formation Fecal formation
Defecation Metabolism Within the cells, nutrients are changed into
energy
Aerobic metabolism Oxidation Anaerobic metabolism Krebs cycle
Metabolism Anabolism and catabolism Thyroid hormones Click here to
play Digestion animation
Animation Digestion Click here to play Digestion animation Effects
of Aging Decrease sensory ability of taste buds
Reduction of saliva Loss of teeth Slowing peristalsis Disorders
Digestive System
Stomatitis Gingivitis Periodontal disease Gastroesophageal reflux
disease (GERD) Disorders Digestive System
Hiatal hernia Heartburn Pyloric stenosis Gastritis Gastroenteritis
Disorders Digestive System
Enteritis Ulcer Inflammatory bowel disease (IBD) Appendicitis
Hepatitis Disorders Digestive System
Cirrhosis Cholecystitis Gallstones Pancreatitis Diverticulosis
Disorders Digestive System
Hemorrhoids Diarrhea Constipation