Chapter 41 - Chapter 41 - Animal NutritionAnimal Nutrition

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I. Types of Digestion- mechanical & I. Types of Digestion- mechanical & chemical breakdown of food into chemical breakdown of food into smaller molecules that can be absorbed smaller molecules that can be absorbed by the cellsby 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

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

II. Nutrition – determined food II. Nutrition – determined food needneed

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

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

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?)

4. nucleid acids – broken down into nucleotides◦a. nucleotide = sugar, phosphate, &

nitrogenous base◦b. only 2 in the known universe – DNA & RNA

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

B. Nutritional requirementsB. Nutritional requirements1. Undernourishment: caloric deficiency2. Overnourishment (obesity): excessive

food intake3. Malnourishment: essential nutrient

deficiency4. Essential nutrients: materials that must

be obtained in preassembled form5. Essential amino acids: the 8 amino

acids that must be obtained in the diet6. Essential fatty acids: unsaturated fatty

acids

Nutritional requirementsNutritional requirements

III. Feeding mechanisms 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)

Suspension, substrate, fluid, or bulk????Suspension, substrate, fluid, or bulk????

IV. Food processingIV. Food processingA. 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

B. Mammalian Digestion (human)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

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

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

through digestive tract

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

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

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

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

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

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

V. Evolutionary adaptationsV. Evolutionary adaptationsA. Dentition: an animal’s assortment of

teethB. Digestive system lengthC. SymbiosisD. Ruminants