1. EQ: WHAT IS THE DIFFERENCE BETWEEN THE ALIMENTARY CANAL AND THE ACCESSORY DIGESTIVE ORGANS? PGS 469-470  If you missed exam on Thursday/Friday, must be made up by Thursday!

2. OBJECTIVES  To compare and contrast chemical vs. mechanical digestion.  To explain the general characteristics of the alimentary canal.  To explain the process of swallowing and peristalsis.  To identify the structures of the mouth and explain their function.  To understand the necessity of salivary glands and name each type.

3. DIGESTION  Chemical digestion- complex molecules are broken down into smaller molecules  Mechanical digestion- physical movement of food that breaks it down into smaller pieces  Ex. Chewing, grinding, mashing  Chewing is called “mastication”

4. COMPONENTS OF DIGESTIVE SYSTEM  Alimentary Canal  “digestive tract”  Mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anal canal  Accessory Structures:  Salivary glands, liver, gallbladder, & pancreas

5. COMPLETE TABLE- GIVE NO MORE THAN 3 WORDS TO DESCRIBE FUNCTION PGS 470-481 Structure (Alimentary Canal)Structure (Accessory Organs) MouthSalivary Glands PharynxLiver EsophagusGallbladder StomachPancreas Small Intestine Large Intestine FRONT OF PAPERBACK OF PAPER

6. EQ: DESCRIBE THE 4 BASIC TISSUE LAYERS, OR TUNICS OF THE ALIMENTARY CANAL. PG 472 (ESOPHAGUS) 1. Grab Digestive System Diagram off front table. 2. Be sure to check Absent folder if you have missed days 3. If you missed exam on Thursday/Friday, must be made up by Thursday!

7. ALIMENTARY CANAL  Muscular tube that passes through the body’s ventral cavity  9 meters long  Contains 4 layers

8. ALIMENTARY CANAL 1. Mucosa: (innermost)  Epithelial Tissue  Protects the tissues beneath it & carries out secretion/absorption 2. Submucosa:  Nourishes surrounding tissue and carries away absorbed materials

9. ALIMENTARY CANAL 3. Muscular Layer:  Two layers of smooth muscle & nerves  Fibers of inner coat, lengthwise  Contraction= shortening  Fibers on outer coat circular  Contraction= decreased diameter 4. Serosa: (outermost)  Protects underlying tissues and secrete serous fluid

10. MOUTH  Mechanical Digestion  Reduces size of solid particles/mixes with saliva ORAL CAVITY

11. SALIVARY GLANDS  Secrete saliva  Amylase (enzyme that breaks down carbs)  Mucus to bind to food and lubricate during swallowing. Salivary Glands Sublingual Submandibular Parotid

12. PHARYNX  Transports bolus (digesting food) to esophagus

13. ESOPHAGUS  About 25 cm long  Connects pharynx to the stomach  Separated from the stomach by the cardiac sphincter. Pharynx Tongue Esophagus Cardiac sphincter

14. DO NOW  Read the story about William Beaumont and his work with St. Martin in the early 1800s.  Write a short summary of what you read.

15. SWALLOWING MECHANISM 1. Food is chewed and mixed with saliva, 2. Tongue rolls this into a bolus forcing it into the pharynx 3. Food stimulates sensory receptors around the pharyngeal opening triggering the swallowing reflex. 4. Momentarily inhibits breathing, peristalsis transports food into the esophagus and to the stomach.

16. MOVEMENTS OF THE ALIMENTARY CANAL  Mixing Movement  Muscles contract rhythmically  Mixes food with digestive juices secreted by the mucosa  Peristalsis-propelling movement

19. DO NOW  Read the story about William Beaumont and his work with St. Martin in the early 1800s.  Write a short summary of what you read.

20. EQ: WHY IS IT NECESSARY FOR THE STOMACH TO BE SO ACIDIC? PGS 485-487 (ACTIVITIES OF THE STOMACH)  Periods 1, 3, 5- turn in Reading Logs from before spring break if you have not already done so.

21. LETS REVIEW!  Without using any notes, trace the pathway of food through the entire digestive system.  Describe what happens to the food between the mouth and the stomach (the remainder of the process, we haven’t discussed yet)

22. STOMACH  J shaped with about a 1 liter capacity.  Contains rugae (ridges) which allow it to expand  Divided into 4 regions  Cardiac  Fundic  Body  Pyloric

23. STOMACH  Mostly Mechanical Digestion  Chemical breakdown of protein begins  Can absorb only small amounts of water, certain salts, alcohol, and some lipid-soluble drugs.  EX: Aspirin

24. STOMACH Cardiac sphincter Pyloric sphincter Stomach

25. GASTRIC JUICE  HCl  Viscous alkaline mucus that coats the stomach  Enzymes  Pepsinogen + HCL  Pepsin (protein breakdown)  Intrinsic factor  Helps the small intestine absorb B12

26. STOMACH JUICES  The mixture of gastric juice and the bolus gives us chyme.  Stomach contractions push chyme a little at a time through pyloric sphincter into the sm. Intestine.  Type of food can effect rate of emptying  Fatty food = 3-6 hrs. in stomach  Proteins quicker  Carbs are fastest

27. HEARTBURN!  Cardiac sphincter contracts and closes to prevent regurgitation.  Heartburn  Regurgitation of stomach acid into the esophagus.

28. STOMACH ULCERS  Breaking down of the mucosal lining.

29. STOMACH

31.  EQ: What is the importance of the microvilli, Villi, and Circular folds in the Small intestine? Pgs 475-477 (Small Intestine)

32. SMALL INTESTINE  Body’s MAJOR digestive organ -- nutrient absorption into the circulatory system  Suspended from posterior abdominal wall by mesentery

33. SUBDIVISIONS OF SMALL INTESTINE 1. Duodenum -- attached to the stomach (5%) 2. Jejunum – middle section (40%) 3. Ileum – attaches to large intestine (60%)

34. Duodenum Jejunum Ilium

35. CHEMICAL DIGESTION IN SMALL INTESTINE 1. FAT digestion begins in the small intestine a. Intestinal & Pancreatic Enzymes b. Bile (liver) enters duodenum 2. Fats  fatty acids + glycerol

36. ANATOMY OF SM. INTESTINE– MEMBRANE LINING 1. Villi—fingerlike structures (“hairs”) 2. Microvilli—tiny projections (“brush border”) 3. Circular Folds- like the rugae of the stomach All meant to increase the surface area of the small intestine for absorption

38. WHAT IS THE DIFFERENCE BETWEEN PERISTALTIC AND SEGMENTAL MOVEMENTS OF THE DIGESTIVE TRACT? PGS 481-482

39.  Peristaltic- Propulsion  Segmental- Mixing

40. PANCREAS  Secretes pancreatic juice into the duodenum through the Pancreatic Duct  Pancreatic enzymes:  Pancreatic amylase  CARBS  Pancreatic lipase  FATS  Nucleases  NUCLEIC ACIDS  Proteases: trypsin, chymotrypsin & carboxypeptidase  PROTEIN

41. Pancreas Pancreatic Duct

42. EQ: DESCRIBE THE PROCESS OF FOOD BREAKDOWN AND ABSORPTION IN THE LARGE INTESTINE. PG 492  Check absent folder if you were out this week.

43. LIVER AND GALLBLADDER  Effects carbohydrate, lipid, and protein metabolism.  Produces bile  Not an enzyme  **bile salts emulsify fats (turn them into little globs instead of big globs!)  Gallbladder- bile storage when food digestion is not occurring

44. Pancreas Pancreatic Duct Common Bile Duct Gallbladder Liver Common Hepatic Duct

45. LARGE INTESTINE (COLON)  “Frames” the small intestine  Colon : Ascending  Transverse  Descending  Sigmoid  Rectum

46. Rectum Colon Transverse Descending Ascending Anal Sphincter Ileocecal Valve Appendix

47. DIGESTION OF LG. INTESTINE  Main Site for uptake of:  WATER  Minerals  Salts  Some Vitamins  Whatever is left unabsorbed, forms feces  Undigested food residues  Mucus  Bacteria  Some water to allow smooth passage

49. REVIEW  What is the process that occurs after swallowing?  What is the scientific name for the digestive tract?  How many layers is this tract?  What are the 3 parts of the pharynx?  What is absorbed in the stomach?  What does the pancreas do?  Why are bile salts important?