 The System The System  Basic Digestive Processes Basic Digestive Processes  Accessory Organs Accessory Organs  Mouth/Esophagus Mouth/Esophagus  Stomach Stomach  Small Intestine Small Intestine  Large Intestine/Rectum Large Intestine/Rectum  Disorders Disorders  Others Others

 Digestion involves 4 major processes: Ingestion  The act of putting the food in your mouth  Mouth Digestion  The physical and chemical breakdown of food into smaller parts  Mouth, Stomach, and Small Intestine Absorption  Absorbing our food into the blood stream  Small Intestine Egestion  The elimination of waste to the external environment  Large Intestine

 Main Structures Mouth Esophagus Stomach Small Intestine Large Intestine Rectum Anus

 Physical Digestion Any physical means by which the surface area of your food is increased  Teeth, Tongue, and Stomach  Chemical Digestion Using chemicals and enzymes to break chemical bonds in food such as carbohydrates, lipids, and proteins  Mouth, Stomach, and Small Intestine

 Secrete chemicals/enzymes that aid in the digestion of food Salivary Glands  Secretes mucus, water, and salivary amylase Liver  Produces bile, which is stored in the gall bladder Gall Bladder  Secretes bile Pancreas  Produces and secretes various digestive enzymes

 Mouth breaks food into small pieces  Salivary Glands secrete watery saliva Salivary Amylase - Starch  Dissacharides  Tongue rolls food into a bolusbolus  When swallowing, our epiglottis covers the trachea to prevent chokingswallowing  Esophagus moves bolus to stomach by peristalsis Wave-like contractions like propel the food forward

 Flanked by the esophageal sphincter and the pyloric sphincter  Rugae (folds) line the interior Allows stomach to expand  Walls secrete gastric juice Hydrochloric acid, enzymes, mucous Pepsin – Proteins  Small Polypeptides  Muscular walls churn the food, now known as Chyme

 Longest portion of the digestive tract  Completes digestion of macromolecules and absorbs their sub-unitssub-units  Ducts from pancreas, liver, and gallbladder connect to duodenum Ducts Pancreas  Protease – Digest proteins  Carbohydrase – Digests starch, polysacch., and disacch.  Lipase – Digests fat  Villi and microvilli increase surface area available for absorption Villi Contain capillaries that uptake macromolecule sub-units

 Main function is to concentrate and eliminate waste  The large intestine holds a large amount of different bacteria E. coli  Helps to absorb water and vitamins  The rectum stores the feces until they are eliminated through the anus

 Tooth Decay Tooth Decay  Ulcers Ulcers  Inflammatory Bowel Disease Inflammatory Bowel Disease Crohn’s Disease Colitis  Gall Stones Gall Stones  Colon Cancer Colon Cancer

 The digestive system is controlled by hormones secreted from the brain