A & P of the Gastrointestinal Tract

1. A & P of the Gastrointestinal Tract By: Sara Anderson

2. Food!!!!! • It is necessary for existence • Pssstt…and it’s darn good too!!!!! • What happens once we chew & swallow it????? • The rest of the world may never know..but YOU will!!!!!

3. AKA: Alimentary Canal Musculoskeletal membranous tube extending from the mouth to the anus Approximately 30 FEET long!!! Digestive Tract

4. Coordinated, rhythmic, serial contraction of smooth muscle that forces food through the digestive tract, bile through the bile duct, and urine through the ureter. **Interesting note** During peristalsis, the tract shortens from approximately 30 feet to 15 feet! What is peristalsis?

5. Accessory Organs • These aid in the digestive tract but AREN’T considered part of the digestive tract: • Teeth • Tongue • Salivary Glands • Liver • Gall Bladder • Pancreas

6. We should all know it all begins at our MOUTHS! TONGUE: Muscular appendage Aids in chewing, swallowing and formation of speech Papillae contain taste buds BITTER, SWEET, SOUR AND SALTY I’m hungry..let’s eat!!!

7. The teeth shred, grind and breakdown Each tooth has a special function Incisors (center) for biting and cutting Canines (posterior incisors) are pointed for tearing and shredding Molars (rear) with 4 cusps are for mastication; crushing and grinding TEETH

8. 3 Pairs: Parotid Submandibular Sublingual Secrete saliva – 99% water with enzymes & mucus 1,000 – 1,500 mL of saliva every day After food is ingested, continue to secrete saliva to cleanse the mouth Salivary amylase (ptyalin) - major enzyme – initiates carbohydrate metabolism Lysozyme – destroys bacteria SALIVARY GLANDS

9. Muscular, collapsible tube approximately 10” long Mouth to thoracic cavity Esophageal hiatus to stomach No digestion takes place here Bolus: broken down food with saliva that moves to the stomach in 5-6 seconds ESOPHAGUS

10. Bolus Transport

11. Located in the LUQ When full it’s the size of a football Holds approximately 1 Liter Entrance- Cardiac sphincter Churns, contracts & compresses contents with gastric juices & water Protein digestion begins Hydrochloric acid softens connective tissue of meat kills bacteria activates pepsin, which converts proteins into proteoses & peptones Mucin- protects stomach lining Intrinsic factor- absorption of B12 Broken down into viscous semiliquid called CHYME Exit- Pyloric sphincter STOMACH

12. STOMACH

13. 90% of digestion 20 feet long 1” diameter Starts at the pyloric sphincter and ends at the ileocecal valve 3 major sections Duodenum Jejunum Ileum Lacteals absorb metabolized fats Intestinal juices finish carb & protein metabolism Bile breaks molecules into smaller droplets Pancreatic juices break down proteins to amino acids Dietary fats to glycerol & fatty acids Starch to simple sugars SMALL INTESTINE

14. SMALL INTESTINE

15. Cecum Appendix Ascending colon Transverse colon Descending colon Sigmoid colon Rectum anus LARGE INTESTINE

16. 2” diameter, 5’ long 4 Major functions Completion of absorption Manufacture certain vitamins Formation of feces Expulsion of feces **NOTE** No function for appendix is known as of today Bacteria Changes chyme into fecal material by releasing remaining nutrients Synthesizes Vitamin K Produces some B-complex vitamins Remaining water & vitamins are absorbed into bloodstream through OSMOSIS LARGE INTESTINE

17. RECTUM • Last 8” of Large intestine • Fecal material is expelled • This is the desired outcome….

18. Largest glandular organ & one of the most complex 3 lbs Divided into 2 lobes 15oo mL of blood are delivered to the liver every minute via the portal vein & hepatic artery Bile Yellow-brown or green-brown color Necessary for metabolism of fats 500-1,000 mL/daily Many functions: Manages blood coagulation Manufactures cholesterol Manufactures albumin (maintains normal blood volume) Filters old RBC’s & bacteria Detoxifying poisons (alcohol, nicotine, drugs) Turns ammonia into urea Main source of body heat Stores back up glycogen Activates Vitamin D Breaks down nitrogenous waste And that’s it!!!!!!!!!! ACCESSORY ORGANS: THE LIVER

19. THE LIVER

20. ACCESSORY ORGANS:THE PANCREAS • Endocrine & EXOCRINE • 1,000 – 1,500 mL juice to aid in digestion • Protease (trypsin), lipase (steapsin), & amylase (amylopsin) digest proteins, fats and carbohydrates • Empties through the duodenum in the papilla of Vater • Contains sodium bicarbonate to neutralize hydrochloric acid

21. THE PANCREAS

22. Hypothalamus 2 centers to stimulate to eat and to STOP eating!!!! And THIS..is your stomach on too much good food!!!!!!!!!!!!! Regulation of food intake!!