Gastrointestinal System

1. Gastrointestinal System

2. What is the Gastrointestinal System? • Digestion • Mechanical and chemical breakdown of foods and the absorption of nutrients • Mechanical digestion breaks large pieces into smaller ones without altering their chemical composition • Chemical digestion breaks food into simpler chemicals

3. Alimentary Canal • Includes • Mouth, Pharynx, Esophagus, Stomach, Small Intestine, Large Intestine, Rectum, and Anus • Accessory Organs • Salivary Glands, Liver, Gallbladder, and Pancreas

4. Mouth • Tongue • Mixes food particles with saliva • Frenulum – connects the tongue to the floor of the mouth • Salivary Glands • Serous Cells • Secrete Amylase which breaks down glycogen • Mucous Cells • Secrete Mucus which lubricates food while swallowing

5. Structure of the Mouth

6. Pharynx and Esophagus • Passageways whose muscular walls function in swallowing • Pharynx connects the nasal and oral cavities with the esophagus • Esophagus connects the pharynx to the stomach • Lower Esophageal Sphincter closes the entrance to the stomach, preventing stomach contents from regurgitating • Peristalsis – a wavelike motion that propels food down a tube • A wave of contraction occurs, pushing down tubular contents • Both lined with stratified squamos epithelium

7. Peristalsis

8. Stomach • J-Shaped pouch-like organ • Gastric Secretions • Chief Cells – Digestive enzyme pepsinogen • Parietal Cells – Hydrochloric Acid • Together form pepsin • Begins the digestion of all types of protein • Pyloric Sphincter • A muscular valve that controls gastric emptying into the Small Intestine

9. Structure of the Stomach

10. Small Intestine • Coiled mass filling most of the abdominal cavity inferior to the stomach and liver – about 6-7 m long • Simple Columnar • Receives secretions from the pancreas and liver, completes digestion of the nutrients in chyme, absorbs the products of digestion, transports the residues to the large intestine • Duodenum • Jejunum • Ileum

11. Digestion of Nutrients • Proteins and Peptides – Amino Acids • Lipids(fats) – Fatty Acids and Glycerol • Carbohydrates – Simple Sugars (monosaccharides)

12. Pancreas and Gallbladder • Pancreas • Secretes pancreatic juice which digests carbohydrates, fats, nucleic acids, and proteins • Pancreatic Lipase • Gallbladder • Absorbs/stores bile between meals • Bile • Yellowish-green liquid which breaks down fat globules into smaller droplets • Also enhances absorption of fatty acids, cholesterol, vitamins A, D, E, and K • Cystic Duct

13. Liver • General functions : • Carbohydrate metabolism • Lipid metabolism • Protein Metabolism • Storage • Blood filtering • Detoxification • Secretion

14. Liver, Gall Bladder, and Pancreas

15. Large Intestine • About 1.5 m long • Lined with simple columnar epithelium • No longer digests food. Instead, absorbs vitamins created by bacteria • Consists of the colon, cecum, rectum, and anal canal(rectum) • Secretes mucus, absorbs water and electrolytes, forms and stores feces • Rectum uses peristaltic movement to remove fecal matter from the body

16. Large Intestine

17. Links • http://www.wisc-online.com/objects/ViewObject.aspx?ID=NUR2403

18. Diseases of Gastrointestinal System

19. What is Celiac Disease? • Digestive disease that damages the SI • Interferes with absorption of nutrients from food • Cannot tolerate gluten, a protein in: • Wheat • Rye • Barley • Some medicines • Some vitamins • Some lip balms • Mal-absorption and an abnormal reaction to gluten

20. What Happens? • If foods are eaten, or products are used that contain gluten, the immune system responds by damaging and/or destroying villi • Villi are tiny, fingerlike protrusions lining the SI that allow nutrients from food to be absorbed through the walls of the SI into bloodstream • Without villi, a person will become malnourished

21. What are the Symptoms? • Major Symptoms that occur • Abnormal bloating and pain • Chronic diarrhea • Vomiting • Pale, foul-smelling or fatty stool • Weight loss • Short status • Anemia • Bone/joint pain, arthritis, bone loss • Leads to liver diseases and cancers of the intestine

22. What Causes it? • Genetic • Can be triggered by: • Surgery • Pregnancy and childbirth • Viral infection • Severe emotional stress • People with celiac tend to have other disease: • Type 1 Diabetes • Autoimmune Thyroid Disease • Autoimmune Liver Disease • Rheumatoid Arthritis

23. Rate of Occurrence and Misdiagnosis • More than 2 million people in the US or 1 in 133 people • Has been long misdiagnosed, easily confused with: • Irritable Bowel Syndrome • Anemia • Inflammatory Bowel Disease • Diverticulitis • Intestinal infections • Chronic Fatigue Syndrome

24. How its Diagnosed and Treated • Blood tests are done for diagnosis • Biopsy of SI is performed, to check the damage of villi • Cheek swap samples check for DNA containing the Celiac Disease gene • However, there is no known cure • The best cure-> eliminate gluten from diet (i.e. read ingredient labels carefully

25. Comparison of Celiac Villi Celiac Villi Non-Celiac Villi

26. What is Crohn’s Disease? • Inflammation of digestive tract (inflammatory bowel disease) • Any area of the GI tract: mouth to anus • Usually affects the lower part of the SI, called the ileum • Swelling extends deep into the lining of the affected organ • Causes pain and makes the intestines empty diarrhea

27. What Happens? • Blockage of the intestine • Thickens intestinal wall (swelling and scar tissue, narrowing the passage) • Ulcers in the affected areas and into surrounding tissues • Nutritional complications also common in this disease • Deficiencies of proteins, calories, and vitamins are caused by the inadequate dietary intake, intestinal loss of protein, or poor absorption

28. What are the Symptoms? • Overall symptoms: • Abdominal pain in the lower right area • Diarrhea • Rectal bleeding • Weight loss • Arthritis • Skin problems • Fever • Children • Delayed development and stunted growth

29. Rate of Occurrence and Misdiagnosis • Genetic • More often in: • 20-30 years old • Jewish heritage • Can be difficult to diagnose because it is similar to other inflammatory bowel diseases, such as IBS

30. Diagnosis • Can be diagnosed through physical exams and a series of tests • Blood test may be done to check for: • Anemia, which could indicate bleeding in the intestines • A high white blood cell count, which is a sign of inflammation somewhere in the body • Testing a stool sample->reveal if there is bleeding or infection in the intestines • Further testing is required, such as a colonoscopy

31. Treatment • Differs by how severe: • Medications -> help control inflammation, correct nutritional deficiencies, and relieve symptoms • Most require surgery to remove inflamed tissue and treat complications • After surgery, there may be a period of remission but the disease tends to reappear over a person’s lifetime • However, disease is unpredictable-> no set treatment for the disease, range of medication and surgery depends on the severity

32. Intestinal view of the Inflammation of Crohn’s Disease

33. Diseases and Disorders (cont.) • Appendicitis • what it is- an irritation, inflammation, and infection of the appendix. occurs when inside becomes filled with mucus, stool, or parasites (causes swelling) • causes- pain, no purpose but if goes untreated it can burst and lead to infection • symptoms- stomach ache on right side • diagnosis-blood and urine test • most occur between ages 10 and 30 • treatment: removal