Digestive System

1. Digestive System

2. Functions 1. Breakdown of ingested food 2. Absorption of nutrients into the blood

3. Cellular Respiration

4. Alimentary Canal(G.I. Tract) • Mouth • Esophagus • Stomach • Small Intestine • Large Intestines

5. Glands secrete mucous and serous fluid into mouth to aid in bolus formation Amylase is an enzyme which speeds up digestion by breaking down complex starches Saliva also contains antibodies to protect from bacterial infection

6. Tongue – Muscle attached at hyoid and styloid processes of the skull, and by the lingual frenulum • Contains taste buds (Chemoreceptors) which are pockets of cells that extend through tongue epithelium and open at a taste pore • Bitter thresholds are lower than all other taste buds. That is why your get the sour face! Theoretically a protective function.

7. Taste impulses received by taste pore send messages to the hypothalamus via the gustatory afferent axons Brain receives and interprets these tastes

9. Teeth • The role is to masticate (chew) food • Humans have two sets of teeth • Deciduous (baby or milk) teeth beginning forming at 6 months and are usually complete in two years • Permanent teeth begin replacing deciduous teeth by age 6 • By adulthood, 32 total teeth + 4 impacted wisdom

10. Permanent teeth • Replace deciduous teeth beginning between the ages of 6 to 12 • A full set is 32 teeth, but some people do not have wisdom teeth • Structures • Enamel • Composed of calcium (hardest substance in the body) • Protects from chewing and acid breakdown of dentin • Dentin • Main composition of tooth • Gives tooth its shape • Pulp • Contains nerves, blood, and lymph vessels • Cementum • Connects root of tooth to the periodontal ligament • Periodontal Ligament • Anchors tooth in the gingivae • Acts as a shock absorber during chewing

11. Dental Cavities Due to bad dental hygiene bacteria occupy tooth enamel and begin to feed on sugar and left over food substances. Once they begin to feed they secrete lactic acid as a waste Lactic Acid breaks down enamel exposing pulp and nerves. OUCH!!!!!

12. Carnivorous Teeth • Incisors = Cutting • Canines = Piercing • Premolars = Grinding • Molars = Grinding

13. Peristalsis Peristalsis is a series of automatic, coordinated, rhythmic muscle contractions that moves • food through the digestive tract • urine from the kidneys through the ureters into the bladder • bile from the gallbladder into the duodenum

14. The Stomach • Located on the left side of the abdominal cavity • Food enters at the cardioesophageal sphincter; Gastrin is released causing pH to drop stimulating the protein digesting enzyme Pepsin • The muscles of the stomach begin mixing up food and gastric juices to form chyme • Most digestive activity occurs in Pyloric region • Chyme (Digestive food) empties into the small intestine at the pyloric sphincter • Pyloric sphincter is the “controller” of chyme entering small intestine

15. Reverse Peristalsis • Vomiting • A deep breath is taken, the glottis is closed, and the larynx is raised to open the upper esophageal sphincter. Soft Palate is elevated to close of external nares • Diaphragm contracts down to create a negative pressure in the thorax, which facilitates opening of the esophagus and esophageal sphincter • Simultaneously with the downward movement of the diaphragm, the abdominal muscles contract elevating inner gastric pressure. With the pylorus closed and the esophagus open the exit route is clear

16. Ulcer DO NOT Chew gum on an empty stomach Drink Coffee, Soda, Juices on an empty stomach Administer medicines on an empty stomach

17. Small Intestine Subdivisions • Duodenum • Attached to the pylorus of the stomach • Chyme enters from stomach • Enzymes enter from accessory organs • Jejunum • Attaches anteriorly to the duodenum • Ileum • Extends from jejunum to large intestine

18. The Small Intestine • The body’s major digestive organ • Once food enters, Chyme is neutralized and Pancreas begins secreting digestive enzymes • Amylase - Starch • Trypsin - Protein • Lipase - Fat • Majority of body’s nutrients absorption occurs along the length of small intestine • Microvilli • Villi • Food is mixed by segmentation and move through Small Intestine by Peristalsis • The neutralized chyme leaves the Small Intestine through ileocecal valve (connection to large intestine)

21. Digestive Enzymes • When chyme enters the duodenum, proteins and carbohydrates are only partly digested, and fat digestion needs to be carried out • Enzymes aid in the digestive breakdown and absorption of chyme _____________________________________________________________ Bile Salts (Liver & Gallbladder)Pancreatic & Salivary Amylase (Pancreas & Mouth) Fat  Fat Droplets Starch + H2O  Maltose Trypsin & Pepsin (Pancreas) Protein + H2O  Peptides Lipase (Pancreas) Fat Droplets + H2O  Glycerol + Fatty Acids Peptidases (Intestinal Juice) Peptides + H2O  Amino Acids Maltase (Intestinal Juice) Maltose + H2O  Glucose Bile is a thick digestive fluid secreted by the liver and stored in the gallbladder. Facilitates digestion by emulsifying fats into fatty acids, which can be absorbed by the digestive tract

22. Liver Gallbladder Pancreas Accessory Organs Digestive Enzyme Production

23. Liver Produces Bile Produces albumin, cholesterol, and many clotting proteins Enters the duodenum through common hepatic duct Responsible for gluco/glycogenesis Pancreas Produces many digestive enzymes Lipase which breaks down fat Enzymes are secreted into the duodenum to neutralize acidic chyme from the stomach Also produces Insulin and Glucagons Liver & Pancreas

24. Disorders of the Liver & Pancreas • Jaundice • Obstruction of the bile duct due to abnormally large breakdown of RBC’s and excessive Bilirubin • Person appears orange/yellow • Hepatitis • Virus obtained through blood transfusions, sex etc • Destroys healthy liver tissue and can lead to cancer • Cirrhosis • Organ becomes fatty scar tissue replacing normal, active liver tissue

25. Gastroenteritis Bacteria which causes one of the many types of traveler's diarrhea. The infection is usually acquired by eating or drinking contaminated food or water, often raw poultry, fresh produce, or unpasteurized milk Lactose Intolerance Small intestine inability to produce lactase which breaks down lactose Bacteria ferments causing inflammation of small intestine Disorders Small Intestine

26. Large Intestine Large Intestine • Functions • Reabsorb water (approx 5%) to dry out indigestible food • If water is not reabsorbed diarrhea occurs • Mutualistic Symbiotic Bacteria present aids in the production of Vitamin K and some B vitamins • Eliminate feces (75% water/25% solid matter) through defecation reflex

28. Anus • Ending of the large intestine, opens to exterior • Functions in elimination of feces • Feces - • External Voluntary sphincter • Internal, Involuntary sphincter

29. Appendicitis • Inflamed appendix can burst causing severe pain in the abdomen and sever infection in the large intestine • Appendix has no known function

30. Nutrition & Health NutrientSubstance used by the body for growth, maintenance, and repair

34. Categories of Nutrients • Carbohydrates • Most are derived from plants • Exceptions: lactose from milk and small amounts of glycogens from meats • Lipids • Saturated fats from animal products • Unsaturated fats from nuts, seeds, and vegetable oils • Cholesterol from egg yolk, meats, and milk products • Proteins • Complete proteins – contain all essential amino acids • Most are from animal products • Legumes and beans also have proteins, but are incomplete • Vitamins • Most vitamins are used as cofactors and act with enzymes • Found in all major food groups • Minerals • Play many roles in the body • Most mineral-rich foods are vegetables, legumes, milk, and some meats

35. Metabolism • Catabolism ~ Substance is broken down to simpler products ~ Energy is released • Anabolism ~ Larger molecules are built from smaller ones ~ Energy Required The sum of all chemical reactions necessary to maintain life

36. Basal Metabolic RateB.M.R. AgeBMR Equation Males0-3 (60.9 x wt) - 54 3-10 (22.7 x wt) + 495 10-18 (17.5 x wt) + 651 18-30 (15.3 x wt) + 679 30-60 (11.6 x wt) + 879 >60 (13.5 x wt) + 487 Females 0-3 (61.0 x wt) - 51 3-10 (22.5 x wt) + 499 10-18 (12.2 x wt) + 746 18-30 (14.7 x wt) + 496 30-60 (8.7 x wt) + 829 >60 (10.5 x wt) + 596 Wt (kg) = wt (lbs) / 2.2lbs/kg

37. Body Mass IndexB.M.I. • Convert your weight in pounds to kilograms by dividing by 2.2 • Convert your height in feet to inches (1 foot = 12 inches). • Convert your height to meters: multiply your height in inches by 2.54. The divide by 100 • Multiply your height (in meters) by itself.  • Divide your weight in kilograms (step 1) by your height squared (step 4) 

39. Body Mass IndexB.M.I. • Convert your weight in pounds to kilograms by dividing by 2.2 • 210lbs / 2.2kg = 95.45kg • Convert your height in feet to inches (1 foot = 12 inches). • 5’10’’ = 70’’ • Convert your height to meters: multiply your height in inches by 2.54. The divide by 100 • 70’’ x 2.54 = 177.8m ~~~~~~~~~~~~~~~ 177.8m/100 = 1.778 • Multiply your height (in meters) by itself.  • 1.778 x 1.778 = 3.16 • Divide your weight in kilograms (step 1) by your height squared (step 4) • 95.45kg/3.16m2 = 30.2

40. BMI Categories Underweight:Less than 18.5 Normal weight:18.5 - 24.9 Overweight:25 - 29.9 Obese:30 or higher

42. The Blueprint The way the body should look!