Chapter 41 - Animal Nutrition

1. Chapter 41 - Animal Nutrition

2. Negative feedback

3. I. Types of Digestion- mechanical & chemical breakdown of food into smaller molecules that can be absorbed by the cells • A. intracellular- • 1. digestion inside a cell • 2. occurs when a lysosome w/digestive enzymes merges w/ a food vacuole • 3. ex: paramecium

4. B. extracellular digestion – • 1. food digested in a gastrovascular cavity • 2. then absorbed by individual cells • 3. most animals use this process

5. II. Nutrition – determined food need • A. Organic cmpds. • 1. carbohydrates- • a. contain CHO • b. broken down into glucose to be used as a supply of energy • c. ex: sugars, starches

6. 2. lipids – fats • a. saturated – all carbons bonded with single bonds, mostly from animals, solid at room temp • b. unsaturated – some carbons have double bonds, mostly from plants, liquid at room temp • c. used for energy storage, protection, insulation, cell membrane • d. broken down into glycerol & fatty acids

7. 3. proteins • a. made of amino acids – your body breaks them down into these aa’s & makes new proteins with them • b. animal products provide all necessary aa’s • c. plant products lack some…(vegans?)

8. 4. nucleid acids – broken down into nucleotides • a. nucleotide = sugar, phosphate, & nitrogenous base • b. only 2 in the known universe – DNA & RNA

9. 5. vitamins – organic cmpds needed in minute amts to help body use other nutrients appropriately • *6. inorganic cmpds – • a. minerals – • 1) don’t contain carbon • 2) needed in minute amts

10. B. Nutritional requirements • 1. Undernourishment: caloric deficiency • 2. Overnourishment(obesity): excessive food intake • 3. Malnourishment: essential nutrient deficiency • 4. Essential nutrients: materials that must be obtained in preassembled form • 5. Essential amino acids: the 8 amino acids that must be obtained in the diet • 6. Essential fatty acids: unsaturated fatty acids

12. Nutritional requirements

13. III. Feeding mechanisms • A. Opportunistic • 1. Herbivore: eat autotrophs • 2. Carnivore: eat other animals • 3. Omnivore: both • B. Feeding Adaptations • 1. Suspension-feeders: aka filter feeders - sift food from water (baleen whale) • 2. Substrate-feeders: live in or on their food (leaf miner) (earthworm: deposit-feeder) • 3. Fluid-feeders: suck fluids from a host (mosquito) • 4. Bulk-feeders: eat large pieces of food (most animals)

14. Suspension, substrate, fluid, or bulk????

15. IV. Food processing • A. overview • 1-Ingestion: act of eating • 2-Digestion: process of food break down • a. enzymatic hydrolysis • 1) intracellular: breakdown within cells (sponges) • 2) extracellular: breakdown outside cells (most animals) • b. alimentary canals (digestive tract) • 3- Absorption: cells take up small molecules • 4- Elimination: removal of undigested material

17. B. Mammalian Digestion (human) • 1. Mouth--food is masticated in the mouth • a. mixed with saliva which contains amylase • 1) enzyme that begins the chem breakdown of starch into maltose (disaccharide) • 2) food is shaped into a ball or bolus swallowed

19. 2. Pharynx – bolus passes through back of mouth • a. uvula raises up to cover opening to nose • b. epiglottis drops down to cover top of trachea

20. 3. esophagus – bolus passes through tube leading from mouth to stomach • a. peristalsis – muscle action that pushes food through digestive tract

21. 4. stomach – functions • a. food is stored – can expand to store 2-4L • b. mixes food to produce a mixture called chyme • c. physical dig occurs • d. produces gastrin (sight, smell, food in stomach) which stimulates cells to produce gastric juices

22. e. chem digestion occurs • 1) HCl denatures/unfolds the proteins (& kills bacteria) • 2) secretes gastric juice – mix of enzymes & HCl • 3) proteins broken down by pepsin • a) pepsinogen (inactive form of pepsin) produced by stomach cells • b) pepsinogen activated by HCl • c) stomach protected from HCl by mucus lining • d) when mucus lining is “eaten” through – peptic ulcers occur • -caused by bacteria ---treated w/ antibiotics

24. 5. small intestine – bulk of digestion occurs here – 3 sections (duodenum, jejunum, & ileum • a. continues digestion of starch & protein • b. starts digestion of fats & nucleic acids • c. enzymes • 1) wall of SI secretes • a) secretes secretin – stimulates the pancreas to produce bicarbonate • b) proteases – digest proteins (ex: aminopeptidase) • c) phosphatases – digests nucleic acids • d) maltase & lactase – digests disaccharides • e) cholecystokinin – stims gallbladder to release bile & pancreas to release enzymes

25. 2) pancreas – secretes enzymes in an alkaline solution to neutralize HCl • a) trypsin – protease (break down proteins) • b) chymotrypsin – protease • c) lipase – fat break down • d) pancreatic amylase – starch breakdown

26. 3) liver • a) produces bile (alkaline – not an enzyme --stored in gall bladder) • b) bile emulsifies fat – breaks it up into smaller globules so enzymes have a greater surface area to work on • 4) villi & microvilli – finger-like projections “fringe” • a) increase surface area for absorption of digested materials

28. 4. Large Intestine – reabsorbs water from what’s left over of the “food” to form feces or solid wastes • a. feces stored in end of LI, rectum, & pushed out of the body (Valsalva muscle movement) through the anus

29. V. Evolutionary adaptations • A. Dentition: an animal’s assortment of teeth • B. Digestive system length • C. Symbiosis • D. Ruminants