Digestive System

1. Digestive System -- responsible for smell & taste -- moves food around to form a Bolus -- also necessary for speech Mouth -- receives food Tongue -- striated muscle

2. -- Hard Palate ( made up of cranial bones) -- Soft Palate (made up of muscle) Roof of Mouth (separates nose from mouth) -- ends in the Uvula

3. -- allows us to chew food so we can swallow it -- get first baby tooth at about 6 months of age -- we have 20 baby (Deciduous ) teethby age 2 -- lose first baby tooth by age 6 Teeth (considered a developmental milestone)

4. -- Adult usually have 32 teeth between ages 17 and 24 -- the last of these are the Wisdom Teeth Types of Teeth -- 8 incisors for biting -- 4 canines for tearing -- 8premolars (bicuspids) for grinding -- baby molars are replaced by these -- 12 molars (tricuspids) for crushing

5. Enamel Dentin Pulp Nerve Blood Vessels Crown Neck Tooth decay Root Cavities Caries Inflammation of the gums: Gingivitis Gum disease that causes loss of bone & teeth: Peridontitis

6. -- tonsils in back of throat are called: Palatine tonsils (These are the ones removed during a tonsillectomy) (Removal of these is called an Adenoidectomy) Tonsils -- play a minor role in protecting us -- Pharyngeal tonsils are the Adenoids

7. -- sends saliva to the mouth -- saliva contains the enzyme Salivary Amylasewhich starts the chemical digestion Parotid of Carbohydrates gland Sublingual (starches) gland Submandibular gland Salivary Glands

8. Pharynx oropharynx laryngopharynx Epiglottis Esophagus nasopharynx Larynx -- as soon as the bolus hits the back of the throat, we swallow (reflex action) -- the larynx is elevated and moves up under the Epiglottis -- prevent food from entering the larynx -- has 3 openings

9. Esophagus Esophagus or Gastroesophageal sphincter Cardiac sphincter Vomiting is caused by contraction of Heartburn is when the stomach content escapes the diaphragm & abdominal muscles into the esophagus -- pushes food along by: Peristalsis -- food enters the stomach through (also called the Lower EsophagealSphincter)

10. Stomach -- lined inside with smooth muscle -- stores food & starts digestion on Protein -- food is now a pasty, semisolid liquid called: Chyme

11. -- Gastric gland in the stomach produce gastric juices containing: 1. Pepsin (an enzyme) -- breaks proteins into Polypeptides 3. Intrinsic Factor (needed for the -- These juices are released in response to absorption of Vit. B 12) the hormone: 2. Hydrochloric Acid (HCL) Gastrin

12. HCL 1. breaks down the connective tissue in meat 2. kills microorganisms ingested with the food 3. activates the gastric enzyme (changes Pepsinogen to Pepsin) -- doesn't digest food, it:

13. Ulcers are caused by HCL penetrating mucous layer of the stomach -- the entire stomach lining is replaced every 3 days -- once thought due to overproduction of HCL & stress -- now know it is caused by a bacteria called: Helicobacter Pylori (it weakens the gastric mucosal lining) Autodigestion

14. Cardiac sphincter Rugae Duodenum Pylorus -- allows the stomach to expand for storage -- takes stomach 2 to 6 hours to empty

15. -- No food or water is absorbed in Cardiac sphincter the stomach Duodenum Pylorus -- only two non-nutrient substance are absorbed here: Aspirin & Alcohol

16. Cardiac sphincter Duodenum Pylorus Pyloric sphincter -- empties into the small intestines (Duodenum) through the:

17. -- approximately 20 feet in length -- supported by the Mesentary which contains the nerves & blood that supply the small intestines -- divided into three Mesentary sections: small intestines Small Intestines 1. Duodenum (frequent area for ulcers) 2. Jejunum 3. Ileum

18. -- like the stomach, the small intestines contain many glands that produce digestive juices -- small fingerlike projections --the villi increase for absorption & secrete certain the surface area enzymes for completing the digestion of our food Villus

19. -- a small lymph Lacteal vessel in the center of the villus which absorbs fatty acids & glycerol Villus -- Amino Acids & Glucose will be absorbed into the blood stream -- absorption of food molecules involves active transport -- we digest food to make it small enoughto cross the cell membrane

20. So, main functions of the Small 3. Transport undigested food into the large intestines Transverse colon (Sigmoid Cecum Colon) Ascending Descending colon Rectum colon Vermiform Appendix Ileocecal valve Intestines are: 1. Digest food 2. Absorb nutrients Anal canal

21. Vermiform Appendix -- passage through the Large Intestines takes about 3 to 5 days Appendix has no digestive function if inflamed, called: Appendicitis

22. Like the esophagus, the large intestines contain no enzymes --It also contains bacteria Escherichia coli called: -- they produce Vit. K & some B complex vitamins -- also gives off an odor characteristic of stool The large intestine's main function is to absorb electrolytes and water

23. 3 Processes Food Undergoes -- begins in the mouth ends in small intestines -- takes place in the small & large intestines -- any disorders of the digestive system will usually involve problems with 1 or more of these processes Two Main Functions of the Digestive System: -- altering the chemical & physical composition of food: Digestion -- ridding the body of waste material: Elimination Digesting Absorption Metabolism -- the use of thenutrients by the cells

24. When chyme containing lipids or fats enter the duodenum, it releases a hormone called: CCK's stimulates the gallbladder to contract Gallbladder -- pear shaped muscular organ -- this pushes bile through the Common Bile attached to the Ductinto the duodenum ventral surface of the liver -- stores the bile produced by the liver -- concentrates bile Cholecystokinin

25. BILE -- mainly bilirubin which comes from the breakdown of hemoglobin -- produce 2 1/4 pints is produced a day -- contains bile salts which -- also lowers surface tension so fat emulsifiesfats -- breaks large fat -- this makes it easier for droplets are easily distributed in the liquid molecules intosmaller fat molecules the enzyme to act upon bile the fats fat -- contains bile pigment

26. Hepatic duct If the Hepatic Duct is obstructed, bile Common bileduct cannot drain out of the liver to the gallbladder -- bile will be reabsorbed & the bilirubin returned to the blood stream --skin & sclera will take on a yellowish tinge called: Jaundice -- since bile gives feces its color, stools would be: gray-white, chalky colored

27. Hepatic duct Common bileduct If Common Bile Duct is obstructed, bile can't get to the duodenum -- still release CCK, so patient has: severe pain & nausea & vomiting Hemolytic Jaundice is due to a rapid destruction of RBC's

28. LIVER 1. Destruction of old RBC 3. Storage of glucose as glycogen -- a less toxic nitrogen waste made from Ammonia (byproduct of breakdown of Amino Acids) -- largest gland in the body -- is a exocrine gland -- Functions: 2. Production of bile 4. Production of urea

29. 5. Production of Blood Proteins 6. Detoxification of blood 7. Storage of Fat-soluble vitamins -- A -- D -- E -- K

30. Pancreatic duct -- is an endocrine & an exocrine gland -- it sends pancreatic juices with enzymesvia the pancreatic duct to the duodenum for digesting protein, fats & carbohydrates PANCREAS -- secretes hormones Insulin & Glucagon

31. Pancreatic duct -- besides enzymes the pancreatic juices also contain Sodium Bicarbonate to neutralize the gastric juices as it enters the intestines -- the Pancreas releases its enzymes in response to the small intestinehormones: Secretin & CCK

32. -- it is a serous membrane that lines the abdominal cavity & covers the organs located in it -- any organ located behind it, is called: PERITONEUM Retroperitoneal (pancreas, duodenum, kidneys)

33. -- found between the parietal & visceral layers -- encloses most of the small intestines -- contains nerves & arteries that supplies the small intestines -- may play a role in fighting infection -- Two extension of the peritoneum are: 1. Mesentary 2. Greater Omentum -- hangs down over the abdomen

34. Rectum --as stool enters Anal Canal the Rectum, stretch receptors are stimulated sending a Internal Anal Sphincter message to the Spinal Cord. External Anal Sphincter --this causes the urge to defecate & the internal sphincter to relax --this is why we can voluntarily choose to defecate --is made up of skeletal muscles & it surrounds the internal sphincter

35. CarbohydrateDigestion MOUTH Salivary Amylase(Enzyme)(startsbreakdownofstarches) SMALL INTESTINES (Releases Secretin - Hormone) Bicarbonate PANCREAS Pancreatic Amylase & Sodium (Neutralizes Gastric Acids) (Enzyme) Breaks starches into: Maltose-- Malt sugar Sucrose-- Cane sugar Lactose -- Milk sugar

36. SMALL INTESTINES Intestinal Enzymes: (Maltase) (Sucrase)(Lactase) Breaks: (Maltose into Glucose ) (Sucrose into Glucose) (Lactose into Glucose) Glucoseabsorbed through Intestinal Villi into the Blood Stream for use by Cells

37. STOMACH Releases Gastrin (Hormone) causing the release of: Pepsin- (Enzyme) breaksproteinsintopolypeptides HCL -- breaks downconnective tissue in meat and activatesenzyme Activates Protein Digestion

38. (Releases Secretin -- Hormone) PANCREAS Trypsin (Enzyme) & Sodium Bicarbonate Breakspolypeptides into peptides (Neutralizes Gastric Acids) Peptidase (Enzyme) Breaks Peptides into Amino Acids SMALL INTESTINES Amino Acids absorbed through Intestinal Villi into the Blood Stream

39. FAT DIGESTION SMALL INTESTINES Releases Hormones -- Secretin& CCK LIVER ProducesBile PANCREAS Sodium Bicarbonate GALLBLADDER (Neutralizes Bile Gastric Acids) Emulsifies Fats Lipase(Enzyme) Breaks Fat into Fatty Acids&Glycerol Fatty Acids & Glycerolabsorbed through theLactealinto theLymph for storage & use by cells

40. -- using materials for growth & repair MECHANICAL DIGESTION -- includes: chewing (mastication) swallowing peristalsis defecation All the chemical reactions that occur in the cell are known as: METABOLISM 1. Catabolism -- releasing stored energy in food 2. Anabolism