Presentation 04 - Bioenergetics And Digestion in Lower Forms


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Digestion in Lower Forms

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  • gastrovascular
  • Esophagus – no sphincter valve, two-way contraction of esophagus muscles Rumen and reticulum – low partition, intermix, main fermentation <synthesis of vitamins and proteins, breakdown of fibrous feeds> vat teeming with microorganisms (before exposing to gastric juices) Omasum – filter pump to sort food (absorption) Abomasum – true stomach (gastric juices)
  • Presentation 04 - Bioenergetics And Digestion in Lower Forms

    1. 1. Bioenergetics and Digestion
    2. 2. We’ll be discussing <ul><li>Trends and Various Strategies Used by Organisms to Process Food </li></ul><ul><li>Process of Digestion in Man </li></ul><ul><li>Disorders of the Human Digestive System </li></ul>
    3. 3. Core Concepts <ul><li>Nutritional requirements </li></ul><ul><ul><li>Animals are heterotrophs that require food for fuel, carbon skeletons, and essential nutrients. </li></ul></ul><ul><ul><li>Metabolic rate provides clues to an animal’s bioenergetic strategy. </li></ul></ul><ul><li>  Evolutionary adaptations of feeding mechanisms and digestive systems </li></ul><ul><ul><li>Diverse feeding adaptations have evolved among animals. </li></ul></ul><ul><ul><li>Structural adaptations of digestive systems are often associated with diet. </li></ul></ul><ul><ul><li>Symbiotic microorganisms help nourish many vertebrates. </li></ul></ul><ul><li>  Overview of food processing </li></ul><ul><ul><li>The four main stages of food processing are ingestion, digestion, absorption, and elimination. </li></ul></ul><ul><ul><li>Digestion occurs in specialized compartments. </li></ul></ul><ul><ul><li>The oral cavity, pharynx, and esophagus initiate food processing. </li></ul></ul><ul><ul><li>The stomach stores food and performs preliminary digestion. </li></ul></ul><ul><ul><li>The small intestine is the major organ of digestion and absorption. </li></ul></ul><ul><ul><li>Reclaiming water is a major function of the large intestine. </li></ul></ul><ul><ul><li>Hormones regulate digestion. </li></ul></ul><ul><ul><li>Reclaiming water is a major function of the large intestine. </li></ul></ul><ul><li>Nutrition and disorders of the human digestive system </li></ul><ul><ul><li>A healthful diet provides both fuel and building materials. </li></ul></ul><ul><ul><li>Nutritional disorders damage health. </li></ul></ul>
    4. 4. Keywords <ul><li>absorption </li></ul><ul><li>alimentary canal </li></ul><ul><li>amebocytes </li></ul><ul><li>anorexia </li></ul><ul><li>bile </li></ul><ul><li>bolus </li></ul><ul><li>brush border </li></ul><ul><li>bulimia </li></ul><ul><li>cecum </li></ul><ul><li>chyme </li></ul><ul><li>complete digestive tract </li></ul><ul><li>crop </li></ul><ul><li>digestion </li></ul><ul><li>duodenum </li></ul><ul><li>elimination </li></ul><ul><li>endocytosis </li></ul><ul><li>enzyme </li></ul><ul><li>esophagus </li></ul><ul><li>essential nutrient </li></ul><ul><li>extracellular digestion </li></ul><ul><li>filter feeders </li></ul><ul><li>gallbladder </li></ul><ul><li>gastrovascular cavity </li></ul><ul><li>gizzard </li></ul><ul><li>heterotroph </li></ul><ul><li>ileum </li></ul><ul><li>incomplete digestive tract </li></ul><ul><li>ingestion </li></ul><ul><li>intracellular digestion </li></ul><ul><li>jejunum </li></ul><ul><li>large intestine </li></ul><ul><li>liver </li></ul><ul><li>malnutrition </li></ul><ul><li>microvilli </li></ul><ul><li>minerals </li></ul><ul><li>nutrition </li></ul><ul><li>obesity </li></ul><ul><li>pancreas </li></ul><ul><li>peptic ulcers </li></ul><ul><li>peristalsis </li></ul><ul><li>phagocytosis </li></ul><ul><li>pharynx </li></ul><ul><li>salivary glands </li></ul><ul><li>small intestine </li></ul><ul><li>sphincters </li></ul><ul><li>stomach </li></ul><ul><li>undernutrition </li></ul><ul><li>vesicles </li></ul><ul><li>villus </li></ul><ul><li>vitamins </li></ul>
    5. 6. Bioenergetics of an animal <ul><li>Food </li></ul><ul><ul><li>Fuel </li></ul></ul><ul><ul><li>C-skeletons </li></ul></ul><ul><ul><li>essential nutrients </li></ul></ul><ul><li>ATP </li></ul><ul><ul><li>resting metabolism </li></ul></ul><ul><ul><li>activity </li></ul></ul><ul><ul><li>temperature regulation </li></ul></ul><ul><li>Excess for biosynthesis </li></ul><ul><li>85-90% of energy from food is lost as heat </li></ul>
    6. 7. Metabolic rates <ul><li>Metabolism </li></ul><ul><ul><li>Anabolism </li></ul></ul><ul><ul><li>Catabolism </li></ul></ul><ul><li>Resting/ Basal Metabolic Rate (BMR) </li></ul><ul><ul><li>energy/unit mass/hr </li></ul></ul><ul><li>Size and relative metabolic rate are inversely proportional </li></ul>
    7. 8. Do plants have digestive systems? <ul><li>Carnivorous plants with primitive digestive systems </li></ul><ul><li>Habitats with N-poor soils </li></ul><ul><li>Adaptation: occasionally feed on animals </li></ul>Pitcher plant – Heliamphora nutans Flypaper trap – Pinguicula gigantea Sundew– Drosera capensis Venus fly trap– Dionaea muscipula
    8. 9. Evolution of digestion <ul><li>Different types depending on diet and lifestyle </li></ul><ul><li>All must accomplish </li></ul><ul><ul><li>Ingestion </li></ul></ul><ul><ul><li>Digestion </li></ul></ul><ul><ul><ul><ul><li>Mechanical breakdown </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Chemical breakdown </li></ul></ul></ul></ul><ul><ul><li>Absorption </li></ul></ul><ul><ul><li>Elimination </li></ul></ul><ul><li>Digestion occurs in specialized compartments </li></ul>
    9. 10. Intracellular digestion (evolved in single-celled protists, retained in simplest animals) <ul><li>PROTISTS </li></ul><ul><li>Paramecium </li></ul>
    10. 11. Intracellular digestion (Protists, Porifera) <ul><li>SPONGES </li></ul>
    11. 12. Extracellular digestion <ul><li>FUNGI </li></ul><ul><li>Sedentary heterotrophs living in or on food supply </li></ul><ul><li>Saprotroph/parasites </li></ul><ul><li>No internal cavity  release digestive enzymes </li></ul>Image from
    12. 13. Extracellular and intracellular digestion Incomplete digestive system <ul><li>CNIDARIANS </li></ul><ul><li>Hydra </li></ul>Image from
    13. 14. Extracellular and intracellular digestion Incomplete digestive system <ul><li>PLATYHELMINTHES </li></ul><ul><li>Planaria </li></ul>
    14. 15. Extracellular digestion Animals with complete digestive systems <ul><li>NEMATODA to VERTEBRATES </li></ul><ul><li>Earthworms </li></ul><ul><li>20 cm long with ~ 100 segments </li></ul><ul><ul><li>1 st – mouth </li></ul></ul><ul><ul><li>Last – anus </li></ul></ul><ul><li>Eats its way through soil </li></ul>
    15. 16. Feeding adaptations for ingestion
    16. 17. Comparison of vertebrate digestive systems
    17. 18. Mammalian digestion General plan ACCESSORY DIGESTIVE ORGANS Organs of the GI tract
    18. 19. Comparison of mammalian digestive systems (Diet plays an important role in the length and structure)