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Lectures 23, 20 Nov 2003 Chapter 15, Feeding and Digestion Vertebrate Physiology ECOL 437

1. Lectures 23, 20 Nov 2003 Chapter 15, Feeding and Digestion Vertebrate Physiology ECOL 437 University of Arizona Fall 2003 instr: Kevin Bonine t.a.: Bret Pasch. 2. Vertebrate Physiology 437. 1. Feeding and Digestion (CH15) 2. Announcements… -Exams returned next week

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Lectures 23, 20 Nov 2003 Chapter 15, Feeding and Digestion Vertebrate Physiology ECOL 437

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  1. 1 Lectures 23, 20 Nov 2003 Chapter 15, Feeding and Digestion Vertebrate Physiology ECOL 437 University of Arizona Fall 2003 instr: Kevin Bonine t.a.: Bret Pasch

  2. 2 Vertebrate Physiology 437 1. Feeding and Digestion (CH15) 2. Announcements… -Exams returned next week -Powerpoint preview -Eldon Braun Thanks

  3. 3 FEEDING

  4. 4 Feeding Filter Feeding -baleen whales -flamingoes -planktivorous fish with modified gill rakers -amphibian larvae Fluid Feeding -lampreys -vampire bats (analgesic and anticoagulants) (15-3)

  5. 5 Seizing with mouth etc. -Jaws, teeth, beaks -Form and function matched Eryx tataricus Modification for diet (15-7)

  6. 6 Seizing with mouth etc. Modification for diet (15-8) -Form and function matched -Darwin’s Finches in Galapagos

  7. 7 Eunectes murinus Seizing with mouth etc. Most toothed non-mammalian vertebrates have homodont dentition -Exception: Some snakes (15-6) Some snakes also with venom - hemolytic, neurotoxic Viperidae, including rattlesnakes

  8. 8 Front Fanged Hypodermic Duvernoy’s/Venom Gland Heloderma Proteroglyph Elapidae Solenoglyph Viperidae Pough et al. 2001

  9. 9 Joe Slowinski Myanmar, Burma Bungarus multicinctus Multibanded Krait alpha bungarotoxin nicotinic ACh receptor antagonist

  10. 10 … Alethinophidia, Macrostomata, Caenophidia, Colubroidea Elapidae (62 genera, 300 species) Naja spp. - Cobras, coral, and sea snakes - venomous - proteroglyph dentition maxilla longer than that of vipers may have teeth posterior to fang relatively fixed - some with biparental care - most terrestrial are oviparous - most marine are viviparous - corals often mimicked by non-venomous sympatrics Micruroides euryxanthus

  11. 11 Pit Organs multiple origins - vipers, boas, pythons infrared image (pit sensitivity to 0.003 C) Pough et al. 2001

  12. 12 Gastric Brooding Frog Etc. Python regius Rheobatrachus vitellinus

  13. 13 Unidirectional Suction Feeding Pough et al. 2001

  14. 14 Suction Feeding Cryptobranchus alleganiensis Salamanders 1. Jaws open 2. Hyoid apparatus (floor of mouth) drops 3. Muscles keep gills closed A few genera asymmetrical - flexible mandible (cartilage) Figure 9-5 Pough et al. 2001

  15. 15 Suction Feeding Anurans buccal pharyngeal Tadpoles unidirectional spiracle(s) filter feeders - strain - mucus atrial branchial filters Figure 9-6f Pough et al. 2001 Stebbins and Cohen, 1995

  16. 16 Turtle Suction Feeding Bidirectional, no teeth (keratinous beak) 1. Compensatory suction - displaced water 2. Inertial suction - modified hyobranchial - greater expansion Figure 9-13 Pough et al. 2001 Esophogeal modifications - prevent prey escape - Dermochelys, 5 cm spines

  17. 17 Feeding Chamaeleo jacksonii

  18. 18 Hydromantes Projectile Feeding Deban et al. 1997 Salamanders a d c protractor b retractor

  19. 19 Snake Feeding Scolecophidians Ancestral Group Leptotyphlops (teeth lower only) - small gape Mandibular raking - short jaws - many small prey Fig. 4-25 Pough et al. 2001

  20. 20 Snake Feeding Cranial Kinesis Unilateral Feeding - two sides of lower jaw (dentary) unfused - intramandibular hinge - looser streptostylic quadrate Fig. 9-33 Pough et al. 2001

  21. 21 Fig. 9-25 Pough et al. 2001

  22. Geochelone elephantopus 22 ~Terrestrial Feeding Turtles -beak shape thickness (durophagic) motion (Gopherus) Alligator Snapping Turtle Macroclemys temminckii

  23. Egg Eating (e.g., Dasypeltis) elastic neck skin, few teeth, vent. vertebral processes 23 Pough et al. 2001

  24. 24 Digestive Systems Three main types: 1. Batch reactors (in and out, not in vertebrates) Alimentary Canal 2. Continuous-flow/Stirred-tank reactor (in, out when broken down) 3. Plug-flow reactor Often 2,3 combined (e.g., stomach and small intestine)

  25. 25 Digestive Systems Transit time (time to digest), cost, and anatomy variable: -Food quality -Body Size -Temperature (ectotherms) (15-11) (15-12)

  26. 26 Generalized Digestive System 1 1 Salivary glands (mucin) to lubricate Tongue for chemoreception 2 2 3 3 4 4 (15-13)

  27. 27 (15-16)

  28. 28 Generalized Digestive System 1 1 Salivary glands (mucin) to lubricate Tongue for chemoreception 2 2 3 3 4 4 (15-13)

  29. 29 Foregut -Conducting, Storage, Digestion -Esophagus and Stomach Crop in some for storage/regurgitation e.g., Some birds use to grind with pebbles and sand Stomach - food storage - begins digestion (e.g., pepsin) - mechanical mixing (muscular walls) - Monogastric (1 chamber, carnivores and omnivores) - Digastric (> 1 chamber)

  30. 30 Foregut Monogastric Stomach - strong muscular sac/tube - sphincters at both ends - mucus from goblet cells of gastric pit - HCl from parietal cells of gastric gland - pepsinogen from chief cells of gastric gland (15-17)

  31. 31 Foregut (15-18) Digastric Stomach - herbivores - regurgitation 3 1 2 - digestive enzymes 4 Domestic cattle, 1L/min gas! (methane and CO2) - anaerobic fermentation by symbiotic bacteria and protozoans ( Carbohydrates -> sugars and gases ) sugars, amino acids, short FAs into blood

  32. 46 END

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