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1135thLectureMon 13 April 2009Vertebrate PhysiologyECOL 437 (MCB/VetSci 437)Univ. of Arizona, spring 2009Kevin Bonine & Kevin OhFeedingDigestionMetabolismAllometryChapters 5 & 6Scheduling...Geocheloneelephantopus2Housekeeping, Mon 13 April 2009ReadingsToday, Mon 13 Apr: Ch 5&6 (Feeding, Nutrition, Digestion)Wed 15 April: Proposal Due 10amCh 6 (Digestion, Metabolism)LAB: Peer Editing, Exam Review?Fri 17 April: Ch 7 (Metabolism)Fri 13 Feb = Exam 1When to have third exam?When to turn in final research proposal?3FEEDING(Hill et al. Ch 5)4FeedingChamaeleo jacksonii5FeedingFilter Feeding(Suspension Feeding)-baleen whales-flamingoes-planktivorous fish with modified gill rakers-amphibian larvaeFluid Feeding-lampreys-vampire bats(analgesic and anticoagulants)(Eckert 15-3)Behavior & Morphology Matched6-Jaws, teeth, beaks-Form and function matchedSeizing with mouth etc.Modification for diet(15-7)Eryx tataricus27(15-8)Modification for dietSeizing with mouth etc.-Form and function matched-Darwin’s Finches in Galapagos8http://www.mun.ca/biology/scarr/Adaptation_in_Darwins_Finches.htmlDarwin’s FinchesGalapagos Islands, Ecuador9http://www.mun.ca/biology/scarr/Adaptation_in_Darwins_Finches.htmlDarwin’s FinchesGalapagos Islands, Ecuador10Seizing with mouth etc.Most toothed non-mammalian vertebrates have homodontdentition-Exception: Some snakesViperidae, including rattlesnakes(15-6)Some snakes also with venom- hemolytic, neurotoxicEunectes murinus11HelodermaFront FangedHypodermicDuvernoy’s/Venom GlandSolenoglyphProteroglyph ElapidaeViperidaePough et al. 200112Joe SlowinskiMyanmar/BurmaBungarus multicinctusMultibanded Kraitalpha bungarotoxinnicotinic ACh receptorantagonist11 Sept 2001313… Alethinophidia, Macrostomata, Caenophidia, ColubroideaElapidae(62 genera, 300 species)- Cobras, coral, and sea snakes-venomous- proteroglyph dentitionmaxilla longer than that of vipersmay have teeth posterior to fangrelatively fixed- some with biparental care- most terrestrial are oviparous- most marine are viviparous-corals often mimicked by non-venomous sympatricsMicruroides euryxanthusNaja spp.14Pit Organsmultiple origins -vipers, boas, pythonsinfrared imagePough et al. 2001(pit sensitivity to 0.003 C)15Gastric Brooding Frog Etc.Python regiusRheobatrachus vitellinus16Pough et al. 2001UnidirectionalSuction Feeding17Suction FeedingSalamanders1. Jaws open2. Hyoid apparatus (floor of mouth) drops3. Muscles keep gills closedA few genera asymmetrical- flexible mandible (cartilage)Figure 9-5Pough et al. 2001Cryptobranchusalleganiensis18Turtle Suction FeedingBidirectional, no teeth(keratinous beak)1. Compensatory suction-displaced water2. Inertial suction- modified hyobranchial-greater expansionEsophogeal modifications- prevent prey escape-Dermochelys, 5 cm spinesFigure 9-13Pough et al. 2001419Projectile FeedingSalamandersHydromantesDeban et al. 1997abcdretractorprotractor20Fig. 9-25Pough et al. 200121Pough et al. 2001Egg Eating (e.g., Dasypeltis)elastic neck skin, few teeth, vent. vertebral processes22Herbivory-omnivores eat fruits and flowers- true herbivores with specializations:symbionts and gut morphology-smaller indivs eat more nutritious parts-Iguanas (need to acquire symbionts)no parental carecommunal nestinghatchlingseat soiljuvenileseat parental feces23Ontogenetic ChangesMammals?Lactase?24Digestion525Generalized Digestive System(Eckert15-13)123412 (incl. stomach)34Salivary glands (mucin) to lubricateTongue for chemoreception26Foregut-Conducting, Storage, Digestion-Esophagus and StomachCrop in some for storage/regurgitationStomach- begins digestion (e.g., pepsin)- food storage- mechanical mixing (muscular walls)- Monogastric (1 chamber, carnivores and omnivores)- Digastric (> 1 chamber)e.g., Some birds use to grind with pebbles and sand27ForegutMonogastric Stomach- strong muscular sac/tube- sphincters at both ends- mucus from goblet cells of gastric pit- HCl from parietal cellsof gastric gland- pepsinogen from chiefcells of gastric gland(Eckert 15-17)11223328ForegutDigastric Stomach-herbivores-anaerobic fermentationby symbiotic bacteriaand protozoans(Eckert 15-18)-regurgitation1234-digestiveenzymes( Carbohydrates -> sugars and gases )sugars, amino acids, short FAs into bloodDomestic cattle,1L/min gas!(methane and CO2)29Midgut-Chemical digestion and Absorption(~ small intestine)-from stomach through pyloric sphincter into duodenum-alkaline 1-Duodenum (mucus + secretions from liver, pancreas)Bile duct from liver-Bile breaks up fats and neutralizes acidsPancreatic Juice-proteases, lipases, carbohydrases, antacid2-Jejunum (digestion and absorption)3-Ileum(mostly absorption)-Internal symbionts help digest, provide nutrition, vitamins-Gas exchange in some air-breathing fishes(Eckert 15-31)30MidgutAnatomy:-longitudinal smooth muscle-circular smooth muscle-epithelium-submucosa(connective tissue)-mucosa(mucous membrane)(Eckert 15-19)Epithelial cells sloughed rapidly(2x1010cells/day),lining replaced every few days631Midgut-Intestinal Epithelium, SURFACE AREA-aids absorption of digested nutrients-epithelium arrangement:-circular folds-villi with blood vessels-central lacteal (lymph system)-microvilli (2x105per mm2)(Eckert 15-19)(Eckert 15-20)32Midgut-Intestinal Epithelium, SURFACE AREA-intestinal chyme-surface of microvilli:-covered with glycocalyx-mucus and water mixed in-absorption throughepithelialcells-microvilli with actin, interacts with myosin for movement(Eckert 15-20)33(Eckert 15-20)Villi with microvilli(brush border)34Hindgut-Water and Ion absorption; Defecation-reabsorb water and ions at end of small intestine (ilieum) and from large intestine/colon-feces into cloaca/rectum for excretion-cloaca can also be site of urine modification (e.g., birds)-bacterial digestion in hindgut fermenters(especially in cecum)-coprophagy/cecotrophy(e.g., rabbits)35Hindgut-Water and Ion absorption; defecationhorserabbithindgut fermenters(Eckert 15-22)36MotilityContraction of gut and movement of contents:1. Propulsion, expulsion2. Mixing and grinding (enzymes, mechanical digestion)3. Stirring so brush border/epithelial lining gets nutrientsPeristalsis-longitudinal muscle-circular muscle(Eckert 15-24)Move food along...737(Eckert 15-25)Regurgitation, Vomiting?KneadingMovement38ABSORPTION:-Across epithelium of brush border (microvilli)-Glycocalyx has enzymes for final cleavagedisaccharidases, aminopeptidases, phosphatases-Simple Diffusion- fat-soluble substances- small water soluble substances throughregulated aquaporins-


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