ANSC 303 1st Edition Lecture 3Outline of Last Lecture I. Why do animals digest food?II. Functions of Gastrointestinal System III. Basic OrganizationIV. You are what you eat…Outline of Current Lecture I. MonogastricII. RuminantIII. Monogastric - Hindgut FermentationIV. Comparative Physiology a. Simple exampleb. Simple stomachesc. Foregut complexity d. Foregut fermentationV. Mouth VI. MasticationVII. SalivaVIII. EsophagusIX. Reticular GrooveX. Stomach XI. Glandular Stomach XII. Stomach Anatomy a. Esophageal b. Cardiacc. Fundicd. PyloricXIII. Stomach Secretionsa. HClb. Pepsinogen c. Renin These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Current LectureI. MonogastricA. Non-ruminant is more correctB. Examples:a Chickensb Pigsc HumansC. Simple compartment, simple stomach D. Rely on enzymes produced in the pancreas by the animalE. Low fermentation capacity F. Mostly omnivoresG. Low fiber dietsII. Ruminant A. Examples:a Cowsb GoatsB. Compartmentalized stomacha Provides fermentation for eating forageC. HerbivoresD. Fermentation:a Totally digestsb Partially digestsc Transforms itIII. Monogastric - Hindgut Fermentation A. HerbivoresB. They have a simple, singular stomach C. Cecum and colon ferment plant material at the end of the GI tractD. Examples:a Rabbitsb HorsesE. Smaller small intestine, larger large intestineIV. Comparative Physiology A. Simple examplea Mink vs Dogb Mink i. Strict carnivoreii. High quality dietiii. Simple stomach 1. Need high capacity to digest protein iv. Short intestine1. Need for enzymatic processesv. No cecum1. No need for fermentationc Dogi. Omnivoreii. Simple stomach iii. Short intestineiv. Small cecum 1. They can digest plant material if they need toB. Simple stomachsa "good at everything, great at nothing"b Pig/humani. Simple stomach 1/3 of the total GI tractii. Longer intestine 1/3 of the total GI tractiii. Cecum and colon sacculated 1/3 of the total GI tractiv. Larger ability to ferment v. Lose ability to digest protein as effectivelyc Horsei. Simple stomach ii. Short intestineiii. Voluminous cecum and colon iv. Cannot digest proteinC. Foregut Complexity a Chicken b Complex foreguti. There are three sectionsii. Crop1. Holding area2. First place to be exposed to acids and enzymesiii. Proventriculusiv. Gizzards1. Contains rocks2. The rocks are used to break down foodc Limited foregut capability d Ceca: small fermentation capabilities D. Foregut Fermentation a Sheepi. Compartmentalized stomach (largest capacity) ii. Long intestine 1. Needs to be able to abosrb fermentation iii. Short and simple cecum and colon iv. Small large intestine1. There is no need for double fermentation b Kangaroo i. Stomach sacculated and largeii. Simple stomach iii. Short cecum and colonV. Mouth A. Function is prehension (ways you take in food) B. TasteC. Masticatea Chewing foodb Decreases particle sizec Increases surface area sized Larger surface area allows for larger area for enzymes and microbes to work e Prehension differs among speciesi. Cow - tongueii. Horse - lipsiii. Pigs - lower jaw like a shovel D. Feed mixes with salivaVI. MasticationA. Physical reduction of foodB. Especially important to non-ruminant herbivoresC. Mastication is the key to their existenceD. Adaptationsa Carnivores - large canines and incisorsi. They need to tear a lotii. They do not have a large need to chewb Herbivores - specialized molarsi. Lots of chewing and grinding E. Teeth are essential VII. SalivaA. Functions:a Lubricate feed for transport from mouth to stomach b Start enzymatic digestion (only certain species)c Works as a bufferB. Compositiona pH > 7b Water c Inorganic componentsi. Mineralsii. Bufferd Organic compoundsi. Ureaii. Enzymes1. Amylase2. Lipaseiii. MucoproteinsVIII. EsophagusA. Muscular tubeB. Some species can throw up and some cannotC. Pharynx to stomach (cardia)D. Dogs and ruminants striated throughoutE. Angle of attachment in horses discourages regurgitation IX. Reticular GrooveA. Closes opening to rumen B. Also called the esophageal grooveC. Muscular contractions close the grooveD. This allows milk to pass from the esophagus to the abomasumE. That way milk does not ferment F. Milk by-passes the rumen X. Stomach A. This is the big fork in the road between rumens and monogastricsB. Monogastricsa Non-ruminantb One compartment c The size varies among speciesC. Ruminanta 3/4 of abdominal cavities b 4 componentsi. Reticulum ii. Rumen iii. Omasumiv. Abomasum XI. Glandular Stomach A. Glandular: a secreting organ B. Stomach in monogastricsC. Abomasum in ruminants D. Functions:a Mixing of foodb Reservoir for controlled release into small intestinec Production of HCl and pepsinogend Limited absorption:i. Asprinii. Alcohol XII. Stomach Anatomy A. Esophageal a Non-glandularB. Cardiaca Glandularb MucusC. Fundica Glandular b HCl (parietal cells)c Pepsin (chief cells)D. Pylorica Glandular b MucusXIII. Stomach SecretionsA. HCla Parietal cellsb Denatures protein c Kills bacteria d Activates pepsin e Ruptures starch granulesB. Pepsinogen a Chief cellsb Activated to pepsin by HClc Pepsin starts protein digestiond Clotls milkC. Renin a Unique to ruminantb Secreted in the abomasum cClots