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Digestion. I. Introduction. A. Processes. The basic digestive processes  Ingestion , Digestion ( mechanical and chemical ), Absorption ( extra-cellular and intracellular ), and Elimination. Figure 41.7. B. Parts Overview.

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  1. Digestion I.Introduction A.Processes

  2. The basic digestive processes  Ingestion, Digestion (mechanical and chemical), Absorption (extra-cellular and intracellular), and Elimination. Figure 41.7

  3. B.Parts Overview

  4. The basic parts  tube (alimentary canal, G-I tract, etc.) and a series of glands (salivary, liver, pancreas, etc.) Figure 41.8

  5. II.Development A.Simplest

  6. 1. Direct to gastrovascular cavity == Poriferans through Platyhelminthes Poriferans simply absorb molecules gathered from their watery homes. Choanocytes Figure 33.4

  7. 1. Direct to gastrovascular cavity == Poriferans through Platyhelminthes Figure 33.10 Figure 41.7

  8. B.Complex

  9. 1. Alimentary canal == Nemerteathrough theChordates Figure 41.8 How is food moved through the tube? What forces are involved? Why have the segmentation of the tube?

  10. III.Mammalian A.Tube 1. Sections

  11. Figure 41.9

  12. 2. Functions

  13. a. Oral cavity = ingestion, chewing, & chemical digestion teeth, tongue, buccal surfaces, and salivary glands b. Pharynx = move & lubricating food muscular wall and mucous glands c. Esophagus = move, lubricating food, & peristalsis muscular wall and sphincter d. Stomach = churn food & chemical digestion muscular wall and gastric glands

  14. e. Small Intestine = chemical digestion &

  15. e. Small Intestine = chemical digestion & absorption Figure 41.12

  16. e. Small Intestine surface area Figure 41.13

  17. f. Large Intestine = water absorption& packing surface area and muscular wall

  18. g. RectalandAnal Canals = packing & elimination muscular wall

  19. B.Glands & Organs 1. Salivary Glands

  20. Salivary Glands = mucin, salivary amylase, buffers, & antimicrobial agents Saliva to coat food, start carbohydratedigestion, control acidity, and prevent infection

  21. 2. Gastric Glands

  22. Gastric Glands = pepsinogen, HCl, & mucous. Figure 41.11 begin protein digestion, activate pepsinogen to pepsin, and buffer

  23. 3. Liver & Gall Bladder

  24. 3. Liver and Gall bladder = secrete or store bile Figure 41.19 emulsifies fat

  25. 4. Pancreas

  26. Pancreas = secrete numerous digestive enzymes Figure 41.12

  27. C.Absorption

  28. 1. What are the molecules and the mechanism of absorption for each of the ingested nutrient molecules?

  29. D.Regulation 1. Cephalic

  30. Digestion regulation can be divided into the cephalic and the gastric phases? Cephalic phase == nervous response Events: Stimuli related to food starts? Salivary secretions Stimulation of the stomach smooth muscle

  31. 2. Gastric

  32. Gastric phase== nervous response andendocrine input Events: Stimuli is the stretching of the stomach wall? Release of stomach secretions Pancreatic enzymes Liver/GB bile release Smooth muscle stimulation

  33. IV.Comparisons A.Dentition

  34. Dentitionis adapted to accommodate different diets. Types of teeth = incisors, canines, premolars, & molars Figure 41.16

  35. B.Tubular Divisions

  36. Tubular divisionsare adapted to accommodate different diets. Figure 41.18 Figure 41.17

  37. Believe to Achieve.

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