1. Digestive System Animated Introduction

2. The Digestive System Structures The digestive system includes: –Mouth –Pharynx –Esophagus –Stomach –Small intestine –Large intestine Major accessory structures that add secretions to the digestive system include: –Salivary glands –Pancreas –Liver

3. Mouth Salivary glands Stomach Pancreas (behind stomach) Large intestine Small intestine Rectum Gallbladder (behind liver) Liver Esophagus Pharynx Figure 38–10 The Digestive System

4. The Digestive System Organs

6. Mouth = mechanical digestion – Moistens food – Increases surface area so that chemical digestion can begin Salivary glands = produce saliva Pharynx = transfer food from the mouth to the esophagus

7. Esophagus = peristalsis (muscle contraction to move food) Bolus = chewed clump of food X Ray of Chewing

8. Liver = produces bile Gallbladder = stores bile Bile = not an enzyme – Mechanically breaks down fat into smaller droplets Stomach = mechanical & chemical digestion – digestive enzymes & acid (hydrochloric acid) – Chyme = mixture of food, acids, enzymes Pancreas = produces enzymes & insulin (hormone)

9. Small Intestine = digestion, absorption of nutrients into blood stream – Chemical digestion is completed here Large Intestine = water absorption Rectum = storage of undigested food (feces) Anus = eliminates feces

10. Small Intestine

11. Villi – Folds in the small intestine – Increases surface area for absorption of nutrients

12. Small Intestine Villus Circular folds Villi Epithelial cells Capillaries Lacteal Vein Artery Figure 38–14 The Small Intestine Section 38-2

13. The Digestive Enzymes Site Mouth Stomach Small intestine (from pancreas) Small intestine Site Mouth Stomach Small intestine (from pancreas) Small intestine Enzyme Role in Digestion Section 38-2 Salivary amylase Pepsin Amylase Trypsin Lipase Maltase, sucrase, lactase Peptidase Breaks down starches into disaccharides Breaks down proteins into large peptides Continues the breakdown of starch Continues the breakdown of protein Breaks down fat Breaks down remaining disaccharides into monosaccharides Breaks down dipeptides into amino acids.

14. Digestive Disorders / Problems Heart Burn –Stomach acid splashes into esophagus –Failure of sphincter from closing off to prevent stomach contents from moving backwards

15. Ulcers a hole in the stomach wall caused by a bacterial infection that eats away at the lining of the stomach Nausea, vomiting

16. Constipation – feces are evacuated infrequently or with difficulty. – Maybe the result of sluggish peristalsis and excessive removal of water from undigested material making the material hard or stiff. – Insufficient roughage in diet can result in constipation.

17. Diarrhea – Insufficient removal of water from undigested food, feces are watery and evacuation is frequent. – Usually associated with intestinal disturbance such as infection. – Prolonged diarrhea can result in dehydration of body tissues.

18. Anorexia – Severe restriction of food intake – Severe underweight Results – nutritional deficiencies permanent failure of normal growth in females: menstrual periods stop in males: levels of sex hormones fall Depression, Irritability, withdrawl DEATH

19. BULIMIA- eating disorder Inappropriate methods of weight control: episodes of binge eating followed by vomiting RESULTS Depression Irregular menstrual cycle mineral imbalances irregular heartbeat erosion of teeth DEATH

20. GALLSTONES Form when bile hardens into pieces of stone-like material and collect in gallbladder. 2 types of gallstones Cholesterol stones- made of cholesterol Pigment stones- made of bilirubin RESULTS pain in abdominal area, back CAUSES They occur when bile has too much cholesterol

21. APPENDICITIS Infection and inflammation of the appendix. If infection cannot be controlled it may become necessary to remove appendix.