Digestion and nutrition

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Digestive System

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Digestion and nutrition

  1. 1. Digestion and Nutrition Pua Karen Joy D. 1 PSY 4
  2. 2. 2 types of species: <ul><li>Autotroph </li></ul><ul><li>– producers in food chain(i.e. plants). </li></ul><ul><li>– organisms that only need inorganic compounds from their surroundings to acquire nutrition. </li></ul><ul><ul><li>Phototrophs – organisms that carry out photosynthesis. </li></ul></ul><ul><ul><li>Chemotrophs –organisms w/c gain energy from inorganic chemical reactions. </li></ul></ul>
  3. 3. 2 types of species: <ul><li>Heterotroph </li></ul><ul><li>– consumers (i.e. almost all of animals). </li></ul><ul><li>– takes in autotrophs as food. </li></ul>
  4. 4. Animal division according to dietary habits <ul><li>Herbivorous – plant eating animals. </li></ul><ul><li>Carnivorous – herbivore/carnivore eating animals. </li></ul><ul><li>Omnivorous – animal and plant eating animals. </li></ul><ul><li>Saprophagous – animals who eat decaying organic matter. </li></ul>
  5. 5. Food processing <ul><li>Ingestion – food taken by mouth or mouth-like structure. </li></ul><ul><li>Digestion – breaking down of food particles. </li></ul><ul><li>Absorption – digested food particles are absorbed to the circulatory system & transported to body’s tissues. </li></ul><ul><li>Excretion – waste products not needed for the body is egested in feces. </li></ul>
  6. 6. Feeding Mechanisms <ul><li>Feeding on particulate matter </li></ul><ul><ul><ul><li>feeding on food particles. </li></ul></ul></ul><ul><li>Feeding on Food Masses </li></ul><ul><ul><ul><li>feeding on solid food. </li></ul></ul></ul><ul><li>Feeding on Fluids </li></ul><ul><ul><ul><li>Feeding on liquid substance. </li></ul></ul></ul>
  7. 7. On particulate matter <ul><li>Suspension feeding </li></ul><ul><ul><ul><li>Organisms w/c use ciliated surfaces to produce currents that draw food to their mouth. </li></ul></ul></ul><ul><ul><ul><li>Filter feeding –organisms having filtering structure w/c feeds by straining food particles from water. </li></ul></ul></ul>barnacles fan worms Spiral tube worms
  8. 8. On particulate feeding <ul><li>Deposit feeding </li></ul><ul><ul><li>obtaining nutrients from particles suspended in soil. </li></ul></ul>earthworm Amphitrite ornata
  9. 9. On Food Masses <ul><li>Carnivorous animals use their teeth for seizing and has a retractable stomach for large intake of intact preys. </li></ul><ul><li>Invertebrates (birds) have teeth-like structures (bills, beaks) for seizing preys. </li></ul>Dasypeltis Raven (generalized bill) Cardinal (seed cracker) Parrot (nut cracker)
  10. 10. On Food Masses <ul><li>Mammals are the only beings who chew their foods. </li></ul><ul><ul><li>has 4 different types of teeth: </li></ul></ul><ul><ul><ul><li>Incisors –biting, cutting, stripping. </li></ul></ul></ul><ul><ul><ul><li>Canines –seizing, piercing, tearing. </li></ul></ul></ul><ul><ul><ul><li>Premolars –grinding & crushing. </li></ul></ul></ul><ul><ul><ul><li>Molars –grinding & crushing. </li></ul></ul></ul>
  11. 11. On Fluids <ul><li>Common organisms that feed on fluids are parasites. </li></ul><ul><li>2 kinds: </li></ul><ul><ul><li>Endoparasites (internal parasites) –feeds upon inside the unknowing host. </li></ul></ul><ul><ul><li>Ectoparasites (external parasites) –feeds outside of the host’s body. </li></ul></ul>hookworms leech lamprey Ectoparasites Endoparasites
  12. 12. Other ectoparasites have piercing and sucking mouthparts just like mosquitoes and lampreys. <ul><li>Life cycle of lamprey </li></ul><ul><li>Sucking mouth part of mosquito </li></ul>
  13. 13. DIGESTION <ul><li>The process of digestion is mechanically and chemically breaking down of solid foods into small particles for absorption. </li></ul><ul><li>Solid foods must be broken down first to their simplest molecular form for it to be assimilated. </li></ul>
  14. 14. Types of digestion <ul><li>Intracellular digestion </li></ul><ul><ul><li>Digestion w/in a cell. </li></ul></ul><ul><ul><li>Food particle is enclosed by food vacuole via phagocytosis. </li></ul></ul><ul><ul><li>Exclusively used by sponges and protozoa. </li></ul></ul>
  15. 15. Types of digestion <ul><li>Extracellular digestion </li></ul><ul><ul><li>Digestion outside the cell. </li></ul></ul><ul><ul><li>Digestion of large food masses. </li></ul></ul><ul><ul><li>Mouth-to-anus alimentary system. </li></ul></ul><ul><ul><li>Practiced by arthropods and vertebrates. </li></ul></ul><ul><ul><li>Ingested food is exposed to mechanical, chemical & bacterial treatments, to diff. acidic & alkaline regions, & to digestive juices added throughout passing the alimentary canal. </li></ul></ul>
  16. 16. Digestive enzymes <ul><li>Are hydrolytic enzymes or hysrolases. </li></ul><ul><li>Food molecule is split by process of hydrolysis . </li></ul><ul><li>Hydrolysis -a chemical reaction in which a compound reacts with water, causing decomposition and the production of two or more other compounds, e.g. in the conversion of starch to glucose. </li></ul><ul><li>**Enzymes –important biochemical catalyst. </li></ul>
  17. 17. Motility in Alimentary Canal <ul><li>Food is moved by cilia or specialized musculature . </li></ul><ul><li>*cilia – tiny projecting thread that beats rhythmically to aid the movement of a fluid past the cell or movement of the organism through liquid. </li></ul><ul><li>Characteristic gut movement: </li></ul><ul><ul><li>Segmentation – alternative constriction of rings of smooth muscle of the intestine that constantly divide & squeeze contents back & forth. </li></ul></ul>
  18. 18. Motility in Alimentary Canal <ul><li>Characteristic gut movement: </li></ul><ul><ul><li>Peristalsis – sweeps food down the gut w/ waves of contraction of circular muscle behind and relaxation in front of the food mass. </li></ul></ul>peristalsis segmentation
  19. 19. Regional function of Alimentary Canals <ul><li>5 major regions of alimentary canal </li></ul><ul><ul><li>Reception </li></ul></ul><ul><ul><li>Conduction and storage </li></ul></ul><ul><ul><li>Grinding and early digestion </li></ul></ul><ul><ul><li>Terminal digestion and absorption </li></ul></ul><ul><ul><li>Water absorption and concentration of solids </li></ul></ul>
  20. 20. I. Reception <ul><li>Buccal cavity </li></ul><ul><ul><li>Mouth. </li></ul></ul><ul><li>Pharynx </li></ul><ul><ul><li>throat </li></ul></ul><ul><ul><ul><li>Salivary gland </li></ul></ul></ul><ul><ul><ul><ul><li>buccal gland </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Produce lubricating secretions containing mucus to assist swallowing. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Secretes toxic enzymes for struggling preys. </li></ul></ul></ul></ul><ul><ul><ul><li>Amylse </li></ul></ul></ul><ul><ul><ul><ul><li>Carbohydrate-splitting enzyme. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Begins hydrolysis of plant and animal starches. </li></ul></ul></ul></ul>
  21. 21. I. Reception <ul><li>* Maltose –two-glucose fragment. </li></ul><ul><ul><li>Tongue </li></ul></ul><ul><ul><ul><li>vertebrate innovation attached to the floor of mouth. </li></ul></ul></ul><ul><ul><ul><li>Assists in food manipulation and swallowing. </li></ul></ul></ul><ul><ul><ul><li>Possess taste buds that are used to determine palatability of foods. </li></ul></ul></ul><ul><ul><ul><li>II. Conduction and storage </li></ul></ul></ul><ul><li>Esophagus </li></ul><ul><ul><li>Transfers food to the digestive region. </li></ul></ul><ul><ul><li>Serves as crop to invertebrates. </li></ul></ul><ul><ul><li>* crop – food storage before digestion. </li></ul></ul>
  22. 22. III. Region of grinding & early digestion <ul><li>Stomach </li></ul><ul><ul><li>Provides initial digestion, storage & mixing of food w/ digestive juices. </li></ul></ul><ul><ul><li>Digestive diverticula (pl. diverticulum ) –blind tubules or pouches arising from the main passage. </li></ul></ul><ul><ul><li>Cellulase –only enzyme that can digest woody cellulose that encloses plant cells. </li></ul></ul><ul><ul><li>Are U-shaped in carnivores & omnivores. </li></ul></ul><ul><ul><li>Cardiac sphincter –muscular ring at the orifice between the esophagus and stomach that opens reflexively when food enters and closes to prevent regurgitation back into the esophagus. </li></ul></ul>
  23. 23. II. Region of grinding & early digestion <ul><li>Duodenum -1 st region of small intestine. </li></ul><ul><li>Pyloric sphincter –regulates flow of food into the intestine and prevents regurgitation into the stomach. </li></ul><ul><li>Deep tubular glands secrete gastric juice 2 liters/day in humans. </li></ul><ul><ul><li>Goblet cell –secrete mucus. </li></ul></ul><ul><ul><li>Chief cells –secrete pepsinogen. </li></ul></ul><ul><ul><li>Parietal/Oxyntic cells –secrete hydrochloric acid. </li></ul></ul><ul><ul><li>**pepsinogen –precursor of pepsin. </li></ul></ul><ul><ul><li>*Rennin –milk-curdling enzyme found in stomachs of ruminant mammals. </li></ul></ul>
  24. 24. III. Grinding and early digestion <ul><li>Happens in intestine. </li></ul><ul><ul><li>Villi –minute finger-like projection in the small intestine. </li></ul></ul><ul><ul><li>Microvilli -a microscopic hair-shaped cell that projects from the surface of the lining of the small intestine. </li></ul></ul><ul><ul><li>Pyloric sphincter -is a strong ring of smooth muscle at the end of the pyloric canal and lets food pass from the stomach to the duodenum. </li></ul></ul><ul><ul><li>Pancreatic juice & bile – has high bicarbonate content. </li></ul></ul><ul><li>Pancreatic enzymes </li></ul><ul><ul><li>Trypsin & chromotrypsin – highly specific proteases that split peptide bonds deep inside a protein molecule. </li></ul></ul><ul><ul><li>Carboxypeptidase –removes amino acid from carboxyl ends of polypeptides. </li></ul></ul><ul><ul><li>Pancreatic lipase –hydrolyzes fats into fatty acids and glycerol. </li></ul></ul><ul><ul><li>Pancreatic amylase –starch-splitting enzyme. </li></ul></ul><ul><ul><li>Nucleases –degrade RNA & DNA to nucleotides. </li></ul></ul>
  25. 25. IV. Grinding and early digestion <ul><li>Membrane enzyme </li></ul><ul><ul><li>Aminopeptidase –splits terminal amino acids from amino end of short peptides. </li></ul></ul><ul><ul><li>Alkaline phosphatase –enzyme that attacks a variety of phospate compunds, nucleotidases & nucleosidases. </li></ul></ul><ul><li>Bile </li></ul><ul><ul><li>Is secreted in the bile duct. </li></ul></ul><ul><ul><li>Collects in the gallbladder between meals. </li></ul></ul><ul><ul><li>Contains no enzyme. </li></ul></ul><ul><ul><li>Bile salts –essential for digestion of fats. </li></ul></ul><ul><ul><ul><ul><li>Bile pigments –produces yellow-green color of bile. </li></ul></ul></ul></ul>
  26. 26. V. Region of water absorption & concentration in solids <ul><li>Happens in the large intestine. </li></ul><ul><ul><li>Large intestine –consolidates remnants of digestion. </li></ul></ul><ul><ul><ul><li>Rectal gland –absorbs water and ions as needed. </li></ul></ul></ul>Large intestine
  27. 27. Regulation of Food intake <ul><li>Hunger centers –located in the hypothalamus. </li></ul><ul><li>Brainstem –regulate the intake of food. </li></ul><ul><li>Brown fat –dark adipose tissue specialized in generation of heat present in placental mammals. </li></ul><ul><li>Uncoupling protein –acts to uncouple the production of ATP during oxidative phosphorylation. </li></ul><ul><li>Thermogenesis –heat production in the body thru metabolic process </li></ul><ul><li>Leptin –hormone w/c tells the hypothalamus & brainstem how much fat the body carries. </li></ul>
  28. 28. Regulation of Digestion <ul><li>Gastrointestinal(GI) hormone </li></ul><ul><ul><li>Group of hormone secreted by enteroendocrine cells. </li></ul></ul><ul><ul><li>Gastrin –a polypeptide hormone that stimulates secretion of gastric acid . </li></ul></ul><ul><ul><li>Cholecystokinin (CCK) –a polypeptide hormone that stimulates gallbladder contraction (increasing bile salts into the intestine), stimulates enzyme-rich secretion in the pancreas, & contributes a feeling of satiety after a meal particular those rich in fat. </li></ul></ul><ul><ul><li>Secretin –secreted in response to food and strong acid in the stomach and small intestine. </li></ul></ul>
  29. 29. Nutritional requirements <ul><li>For Animals: </li></ul><ul><ul><li>Carbohydrates & fats- fuel for energy. </li></ul></ul><ul><ul><li>Proteins (amino acids) –synthesis of specific proteins and other nitrogen-containing compunds. </li></ul></ul><ul><ul><li>Water –solvent for body chemistry, major component of all fluids of the body. </li></ul></ul><ul><ul><li>Mineral – inorganic elemental atoms that are essential nutrients. </li></ul></ul><ul><ul><li>Salts –(inorganic) forms structural & physiological components throughout the body. </li></ul></ul><ul><ul><li>Vitamins - organic compound required as a nutrient in tiny amounts by an organism. </li></ul></ul>
  30. 30. Undernourishment/Malnourishment <ul><li>#2 world’s oldest problem & today’s major health problem. </li></ul><ul><ul><li>*Atherosclerosis – disease that occurs when a diet is high in saturated lipids but low in polyunsaturated lipids. </li></ul></ul><ul><li>Growing children, pregnant & lactating women are most vulnerable to effects of malnutrition. </li></ul>atherosclerosis Malnutrition

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