1. 1 The Digestive System

2. 2 Digestion Processing of food Types –Mechanical (physical) Chew Tear Grind Mash Mix –Chemical Catabolic reactions Enzymatic hydrolysis –Carbohydrate –Protein –Lipid

3. 3 Digestion Phases –Ingestion –Movement –Digestion –Absorption –Further digestion

4. 4 Digestive System Organization Gastrointestinal (Gl) tract (Alimentary canal) –Tube within a tube –Direct link/path between organs –Structures Mouth Oral Cavity Pharynx Esophagus Stomach Duedenum Jejenum Ileum Cecum Ascending colon Transverse colon

5. 5 Digestive System Organization Descending colon Sigmoid colon Rectum Anus Accessory structures –Not in tube path –Organs Teeth Tongue Salivary glands Liver Gall bladder Pancreas

6. 6 Anatomy of the Mouth and Throat

7. 7 Human Deciduous and Permanent Teeth

8. 8 Dorsal Surface of the Tongue

9. 9 The Major Salivary Glands

10. 10 Deglutition (swallowing) Sequence –Voluntary stage Push food to back of mouth –Pharyngeal stage Raise –Soft palate –Larynx + hyoid –Tongue to soft palate –Esophageal stage Contract pharyngeal muscles Open esophagus Start peristalsis

11. 11 Deglutition (swallowing) Control –Nerves Glossopharyngeal Vagus Accessory –Brain stem Deglutition center –Medulla oblongata –Pons –Disorders Dysphagia (difficulty swallowing) Aphagia (inability to swallow; may be psychological or physical)

12. 12 Esophagus Usually collapsed (closed) Functions –Secrete mucous –Transport food

13. 13 Peristalsis and Segmentation

14. 14 Esophagus Sphincters –Upper –Lower Abnormalities –Achalasia- difficulty swallowing, backflow –Atresia- esophagus does not connect to stomach properly –Hernia –Barret’s esophagus- lining damaged by stomach acid –Esophageal varices- bleeding in esophagus

15. 15 Stomach Usually “J” shaped Left side, anterior to the spleen Mucous membrane –G cells – make gastrin –Goblet cells – make mucous –Gastric pit – Oxyntic gland – Parietal cells – Make HCl –Chief cells – Zymogenic cells Pepsin Gastric lipase

16. 16 Anatomy of the Stomach

17. 17 Stomach 3 muscle layers –Oblique –Circular –Longitudinal Regions –Cardiac sphincter –Fundus –Antrum (pylorus) –Pyloric sphincter Vascular Inner surface thrown into folds – Rugae Contains enzymes that work best at pH 1-2

18. 18 Stomach Functions –Mix food –Reservoir –Start digestion of Protein Nucleic acids Fats –Activates some enzymes –Destroy some bacteria –Absorbs Alcohol Water Lipophilic acid B 12

19. 19 Small Intestine Extends from pyloric sphincter  ileocecal valve Regions –Duodenum –Jejenum –Ileum Movements –Segmentation –Peristalsis

20. 20

21. 21 Small Intestine Chemical digestion of nutrients and absorption of nutrients is completed in the small intestines Three divisions of the small intestines: Duodenum – first portion of the small intestine where the majority of chemical digestion occurs. Jejunum – middle portion of the small intestine where the majority of absorption of nutrients occurs. Ileum – final portion of the small intestine where absorption occurs.

22. Large Intestines The large intestines are the last part of the digestive system. Absorption of water, vitamins, electrolytes, production of vitamin K, and formation of feces occurs in the large intestines Ascending, Transverse, Descending, Sigmoid colons

23. 23 Anatomy of the Large Intestine

24. 24 Large Intestine Functions –Mechanical digestion Haustral churning Peristalsis Reflexes –Gastroileal –Gastrocolic –Chemical digestion – Bacterial digestion Ferment carbohydrates Protein/amino acid breakdown – Absorbs More water Vitamins – B – K – Concentrate/eliminate wastes

25. 25 Feces Formation and Defecation Chyme dehydrated to form feces Feces composition –Water –Inorganic salts –Epithelial cells –Bacteria –Byproducts of digestion Defecation –Peristalsis pushes feces into rectum –Rectal walls stretch Control –Parasympathetic –Voluntary

26. Rectum The last portion of the large intestine which functions as a temporary storage of solid wastes before excretion

27. Anus The final portion of the rectum where solid waste is excreted from the body

29. 29 Liver Location –R. Hypochondrium –Epigastric region Functions –Makes bile Detergent – emulsifies fats

30. 30 Liver –Detoxifies/removes Drugs Alcohol –Stores Glycogen Vitamins (A, D, E, K) Fe and other minerals Cholesterol –Activates vitamin D –Fetal RBC production –Metabolizes absorbed food molecules Carbohydrates Proteins Lipids

31. 31 Liver Dual blood supply –Hepatic portal vein Direct input from small intestine –Hepatic artery/vein Direct links to heart

32. 32 The Duodenum and Related Organs

33. 33 The Organs and Positions in the Abdominal Cavity

34. Diseases and Disorders of the Digestive System

35. Colon Cancer Most of the cancers of the large intestine are believed to have developed from polyps (benign tumors). Cancer of the colon and rectum, also called colorectal cancer can invade and damage adjacent tissues and organs. Symptoms include fatigue, weakness, shortness of breath, change in bowel habits including diarrhea or constipation, red or dark blood in stool, weight loss, abdominal pain, cramps, or bloating. Surgery is the most common treatment for colon cancer. Quick Write: Who is more likely to get colon cancer, men or women?

36. From Donna Myers, former About.com Guide Updated: July 8, 2007 About.com Health's Disease and Condition content is reviewed by the Medical Review BoardDonna MyersMedical Review Board Research has shown that in general, men are more likely to have colon polyps and colon tumors than women.colon polyps Female smokers were more likely to get colorectal cancer than male smokers. So, all other things being equal, if a man and a woman smoke, the woman is more likely to get colorectal cancer.smokers Men tend to get rectal cancer and left-sided colon cancers more often than women, and women tend to get right-sided colon cancer more often than men.rectal cancercolon cancers

37. Chron’s Disease Chron’s disease is an ongoing disorder that causes inflammation of the digestive tract. The disease can affect any area of the GI tract, from the mouth to the anus, but it most commonly affects the lower part of the small intestine, the ileum. The swelling extends deep into the lining of the affected organ. The swelling can cause pain and can make the intestines empty frequently, resulting in diarrhea. Chron’s disease may be caused by an abnormally functioning immune system. Treatment includes prescription medications, nutritional supplements, surgery, or a combination of these. There is no cure.

38. from ehealthmd.com/chron’s disease Compromised nutrition, even malnutrition, is a constant threat to an individual with Crohn's disease. This is because the disease creates a vicious cycle: Fever and diarrhea cause a loss of appetite. Fever, by raising the body's metabolic rate, adds to the need for caloric energy. Diarrhea can lead to dehydration and temporary lactose intolerance (the inability to digest milk sugars). Lactose intolerance causes milk sugars to ferment in the colon, leading to cramps and more diarrhea. Lactose intolerance can also indirectly lead to calcium deficiency, which in turn can lead to the loss of bone density called osteoporosis. This side effect can be especially prevalent among those being treated with corticosteroids such a s prednisone.

39. Celiac Disease Celiac disease is a digestive disease that damages the small intestine and interferes with absorption of nutrients from food. People who have celiac disease cannot tolerate a protein called gluten, found in wheat, rye, and barley. When people with celiac disease eat foods or use products that contain gluten, their immune system responds by damaging the small intestine. Celiac disease is an autoimmune disease that is genetic. The most common symptoms include pain in the digestive system or other parts of the body. The only know treatment is a gluten-free diet.

40. Appendicitis Appendicitis, inflammation of the appendix, is the most common surgical disease. It results from the obstruction of the opening to the appendix by a mass, structure or infection. Symptoms of appendicitis include generalized abdominal pain, pain localized in the lower right abdomen, nausea, vomiting, possibly fever, and an elevated white blood cell count. Treatment involves the removal of the appendix and antibiotics.

41. Hernia hernias occur when a part of the intestine protrudes through a weak point or tear in the abdominal wall. This protrusion creates a bulge which can be painful. Some hernias occur at birth when the abdominal lining does not close properly. Other hernias occur later in life when muscles weaken or deteriorate. The most common treatment is surgery.