The document summarizes the key components and functions of the digestive system. It describes the digestive process which involves breaking down food mechanically and chemically into smaller molecules through digestion and absorption. The digestive system includes the alimentary canal from mouth to anus, accessory organs like the liver, gallbladder and pancreas, and four layers. Digestion occurs through the actions of teeth, saliva, stomach acid, enzymes and peristalsis. Absorption mainly takes place in the small intestine through villi and lacteals. Undigested waste is eliminated as feces through the large intestine and anus.

1. Digestive System Chapter 17

2. Digestion: Breaking down food into the smallest end products EndProducts: Small particles, small enough to pass through cell membrane Absorption: Getting products into the circulation for cells to use EliminateWaste: Bowel Movement

4. Gall Bladder

6. Sympathetic~ Decrease digestive secretions Mucosa Submucosa 3. (2) Layers of smooth muscle run in different directions when the contract causes a wave like motion to push food through digestive system called peristalsis Muscular

7. Layers of the Digestive System 4. Peritoneum: Sirius membrane lining of abdominal cavity and covers digestive organs allows for movement A. Parietal: Lines entire cavity B. Visceral: Internal layer cover over organs in the cavity 1.) Omentum: Towards front fold of membrane start at stomach to the intestine, like an apron covers & helps support. 2.) Mesentery: Covers and attaches to intestine and attaches to posterior abdominal wall supports and holds loops of bowl in place

8. Mouth-Oral Cavity

9. Definitions Roof: Roof of the mouth or oral cavity is made of the HARD (anterior) and SOFT (posterior) Palates Uvula: Hangs down from the soft palate is a V-shaped structure, which assist with swallowing Tongue: Located on the floor of the mouth. The tongue has Three functions 1. Swallowing- Deglutition 2. Taste 3. Production of sound Frenulum: Fold of mucous membrane under the tongue Papillae: Rough elevations on the tongue which contain the taste buds. Teeth: Allows us to perform MASTICATION or chewing. Calcium is the most important mineral for tooth growth.

10. Deciduous: Baby teeth we develop 20 starting at 6 month of and begin to shed at 6 years old. They are replaced by 32 permanent (adult) teeth. Pulp Cavity: Inner area of a tooth which contains nerves and blood supply Enamel: Covers the part of the tooth above the Gingiva (gum) is the hardest substance in the body. Root: Entire tooth under the gum line Crown: Tooth above the gum line

11. Salivary Glands Produce saliva which is made of and a digestive enzyme called Amylase. 1. Parotid: Back of mandible in front of ear 2. Submandibular: Under mandible 3. Sublingual: Under the tongue, floor of mouth

12. The Pharnyx or throat transports food after deglutition or swallowing. The epiglottis closes off the trachea during swallowing Esophagus : 10 inch long tube carrying food away from the pharynx to the stomach. It is lined with mucous membrane and has a muscular wall which performs “peristalsis” (wave like motion to propel food)

14. Located in LUQ, below the diaphragm

15. Lined with mucous membrane that lays in the fold or Rugae when empty.Fundus: Upper section Body: Central Portion Pylorus: Lower narrow end

16. Sphincters Cardiac/Lower Esophageal Sphincter: Between the esophagus and stomach. Between the stomach and small intestines. Pyloric Sphincter:

17. Chyme: When liquid food mixture enters the small intestine

18. Stomach Functions 1.Reservoir: Stores food 2.Secretion: Mucus, HCL, Pepsin(and enzyme that digests protein) and intrinsic factor for absorption of Vit B12 for RBC production. 3. Churns Food- Breaks down food into smaller pieces 4. Absorption- small amounts of water, alcohol(much faster absorption) and some medications.

20. Villi Small projections or villi extends into the lumen. Single cell thick wall. !st function of small intestine- absorption of nutrients from the food we eat. Some end products of digestion pass into the capillaries where they join the venous system. End products of fats are absorbed by lacteals and enter the lymph system for transport to the bloodstream. Glands in the mucous lining of the small intestine secrete mucus and enzyme which help food digestion. (the 2nd function of small intestine) its smooth muscle wall performs peristalsis, pushing digested food to the next structure.

23. Secretion of mucus

26. Stores glucose as glycogen and released prn

27. Stores fat-solube vitamins-A,D,E,K (Carried around on fat particles)

28. Makes plasma protein-albumin for water balance globulins for immunity (antibodies) fibrinogen & prothrombin for clotting

29. Filters blood-filter out toxins

30. Hemolysis-break down of old blood cellsBile contains: bile salts, bile rouben(break down of RBC) cholesterol Function of bile: Emulsification fats Flow: Out of liver through hepatic ducts and common bile duct. Backs up at sphincter and drains empties into gallbladder.

31. Gallbladder-Cholecyst Location: RUQ under(behind) liver Functions: 1. Stores and concentrates bile after produced in liver 2. When chyme enters the small intestines, the gallbladder contracts to eject bile through the cystic duct, into the common bile and then into the duodenum

32. Pancreas -most important organ for digestive enzyme Location: LUQ posterior to stomach Functions: Endocrine Beta cells in the illets of langerhauns secrete insulin to decrease blood glucose. Alpha cells secrete glucagon to increase blood glucose. 2. Exocrine Digestive secretions empty into the pancreatic duct then into the duodenum. HCO3- alkaline substance Enzymes – breakdown all three major nutrients

34. Digestive process B. Absorption: most takes place in small intestine 1.)stomach- alcohol some medications 2.)small intestine- absorption mostly takes place here villi-Blood capillaries through circulation< carbs, proteins Fats- lacteals- lymp- blood 3.) large intestines water is reabsorbed, absorbs vitamins and minerals c. Elimination- eliminate feces Bulk – fiber indigestible substance a. cellulose-(seeds, shells, skins off fruits) Also in feces Bacteria Water Mucus Bile pigments – cause stool to have a dark color

35. THE END!