ANIMAL ANIMAL NUTRITIONNUTRITION

Diverse Feeding Diverse Feeding AdaptationsAdaptations

Suspension Feeders – sift food particles Suspension Feeders – sift food particles from water.from water.

Substrate Feeders – eat their way through Substrate Feeders – eat their way through their food source.their food source.– Deposit Feeders – eating their way through Deposit Feeders – eating their way through

partially decayed matter.partially decayed matter. Fluid Feeders – suck fluids out of a living Fluid Feeders – suck fluids out of a living

host.host. Bulk Feeders – eat large pieces of their Bulk Feeders – eat large pieces of their

prey.prey.

Whale Eating a Seal

41-09-WhaleEatSeal-B.mov 41-09-WhaleEatSeal-S.mov

Four Main Stages of Food Four Main Stages of Food ProcessingProcessing

IngestionIngestion- act of eating.- act of eating. DigestionDigestion – process of breaking food – process of breaking food

down into molecules that can be down into molecules that can be absorbed by the body.absorbed by the body.

AbsorptionAbsorption – absorbing the – absorbing the nutrients into the blood.nutrients into the blood.

Elimination Elimination – ridding the body of – ridding the body of waste.waste.

Digestion Occurs in Specialized Digestion Occurs in Specialized CompartmentsCompartments

Prevents enzymatic hydrolysis of the Prevents enzymatic hydrolysis of the organisms own tissues.organisms own tissues.

Food vacuoles.Food vacuoles. Gastro vascular cavities.Gastro vascular cavities. Alimentary cavities.Alimentary cavities.

Intracellular Digestion Verses Intracellular Digestion Verses Extra Cellular Digestion.Extra Cellular Digestion.

Intracellular DigestionIntracellular Digestion – Food vacuoles ingest food particles that fuse Food vacuoles ingest food particles that fuse

to a lysosome containing hydrolytic enzymes.to a lysosome containing hydrolytic enzymes.– Heterotrophic protists and sponges do this.Heterotrophic protists and sponges do this.

Extracellular DigestionExtracellular Digestion– Occurs outside of cells.Occurs outside of cells.– Gastrovascular cavities – hydra, planariaGastrovascular cavities – hydra, planaria

Incomplete digestion – mouth and anus are the same Incomplete digestion – mouth and anus are the same openingopening

Digestive enzymes secreted by the gastrodermal Digestive enzymes secreted by the gastrodermal cells digest the prey into tiny bits.cells digest the prey into tiny bits.

Alimentary Cavities.Alimentary Cavities.

Digestive tubeDigestive tube Complete digestive tract – mouth and Complete digestive tract – mouth and

anus at opposite ends.anus at opposite ends. Nematodes, Annelids, Mollusks, Nematodes, Annelids, Mollusks,

Arthropods, Echinoderms and Arthropods, Echinoderms and Chordates.Chordates.

Enzymes are secreted by the digestive Enzymes are secreted by the digestive tube and nutrients are absorbed along tube and nutrients are absorbed along the way.the way.

Specialized Structures of the Specialized Structures of the Digestive TubeDigestive Tube

Mouth and pharnyxMouth and pharnyx – where food is taken in. – where food is taken in. EsophogusEsophogus - passage - passage CropCrop – food moistened and stored (insects – food moistened and stored (insects

and birds and annelids)and birds and annelids) GizzardGizzard – food is pulverized (birds and – food is pulverized (birds and

annelids)annelids) IntestineIntestine – enzymes digest food and nutrients – enzymes digest food and nutrients

absorbed.absorbed. AnusAnus – where undigested food and waste – where undigested food and waste

exits.exits.

The Mammalian Digestive The Mammalian Digestive SystemSystem

PeristalsisPeristalsis is the rhythmic contractions of is the rhythmic contractions of smooth muscle along the digestive tract smooth muscle along the digestive tract that keep food moving along.that keep food moving along.

SphintorsSphintors close off various parts of the close off various parts of the tube so that regulating the passage of tube so that regulating the passage of food between chambers.food between chambers.

Salivary GlandsSalivary Glands secrete amylase to secrete amylase to break down starch and lubricate food.break down starch and lubricate food.

PancreasePancrease secretes digestive enzymes. secretes digestive enzymes. LiverLiver produces bile. produces bile. GallbladderGallbladder stores bile. stores bile.

The Oral CavityThe Oral Cavity

ChewingChewing physically breaking the food physically breaking the food into smaller pieces and exposing into smaller pieces and exposing more surface area for enzymes to act more surface area for enzymes to act on.on.

Salivary amylaseSalivary amylase breaks down breaks down starch. Aliva also contains mucin with starch. Aliva also contains mucin with makes food slippery.makes food slippery.

BolusBolus is the ball of food that gets is the ball of food that gets pushed into the esophogus.pushed into the esophogus.

The StomachThe Stomach

Can accommodate about 2 liters of food. Can accommodate about 2 liters of food. Chyme Chyme is what the bolus becomes in the is what the bolus becomes in the

stomach after digestive juices are added.stomach after digestive juices are added. Ridges in the stomach called Ridges in the stomach called ruggaeruggae help help

churn food.churn food. PepsinPepsin breaks down proteins. breaks down proteins.

– PepsinogenPepsinogen is the inactive for of pepsin and is is the inactive for of pepsin and is activated by HCl.activated by HCl.

– HCl also helps denature proteins in the chyme.HCl also helps denature proteins in the chyme.

Digestion in the StomachDigestion in the Stomach A Closer Look A Closer Look

Gastric PitsGastric Pits in the stomach lining in the stomach lining are composed of specialized are composed of specialized epithelial cells.epithelial cells.

Gastric pits create the gastric juices.Gastric pits create the gastric juices.– Parietal Cells Parietal Cells secrete HCl.secrete HCl.– Chief CellsChief Cells secrete pepsinogen. secrete pepsinogen.– Mucus CellsMucus Cells secrete mucus that secrete mucus that

protects the stomach lining.protects the stomach lining.

Feedback SystemsFeedback Systems

Pepsin activates more pepsinogen.Pepsin activates more pepsinogen. The sight of food creates a nervous The sight of food creates a nervous

response that causes gastric juices to response that causes gastric juices to be secreted.be secreted.

A drop in pH and distention of the A drop in pH and distention of the stomach creates a negative feedback stomach creates a negative feedback response.response.

ProblemsProblems

Gastric ulcersGastric ulcers are lesions in the stomach are lesions in the stomach lining.lining.

Can occur when the lining is eroded faster Can occur when the lining is eroded faster that it is replaced.that it is replaced.

Helibacter pyloriHelibacter pylori can cause ulcers but can cause ulcers but can be treated with antibiotics.can be treated with antibiotics.

HeartburnHeartburn occurs when acid chyme occurs when acid chyme seeps back through the seeps back through the cardiac sphintorcardiac sphintor which is the opening between the which is the opening between the esophogus and stomach.esophogus and stomach.

Enter the Small Intestine!Enter the Small Intestine! The The pyloric sphinctor pyloric sphinctor is the opening is the opening

between the small intestine and the stomach.between the small intestine and the stomach. It takes 2 to 6 hours after a meal for the It takes 2 to 6 hours after a meal for the

stomach to empty.stomach to empty. The small intestine is known as the The small intestine is known as the

duodenumduodenum.. The small intestine secretes bicarbonate to The small intestine secretes bicarbonate to

neutralize the acid chyme coming from the neutralize the acid chyme coming from the stomach. stomach.

Bile is secreted by the gallbladder to emulsify Bile is secreted by the gallbladder to emulsify fats which are broken down by an enzyme fats which are broken down by an enzyme called called lipase lipase which is secreted by the small which is secreted by the small intestine.intestine.

Enzyme DigestionEnzyme Digestion CarbohydratesCarbohydrates

– Pancreatic amylasePancreatic amylase secreted by the pancreas secreted by the pancreas breaks down starch.breaks down starch.

– MaltaseMaltase, , SucraseSucrase, , LactaseLactase break down break down disacharrides and are built into the intestinal disacharrides and are built into the intestinal epithelium.epithelium.

Protein DisgestionProtein Disgestion– ChymotrypsinChymotrypsin, , TrypsinTrypsin,,CarboxypeptidaseCarboxypeptidase, ,

AminopeptidaseAminopeptidase, , enteropeptidaseenteropeptidase.. Nucleic AcidsNucleic Acids – – NucleasesNucleases LipidsLipids - - LipasesLipases

Absorption of NutrientsAbsorption of Nutrients Villi and microvilli increase surface area(300mVilli and microvilli increase surface area(300m22) )

for maximum absorption.for maximum absorption. Intestinal epitheium absorb nutrients either by Intestinal epitheium absorb nutrients either by

diffusion or active transport. diffusion or active transport. Nutrients are carried away from the intestine by Nutrients are carried away from the intestine by

capillaries at the core of the villi.capillaries at the core of the villi. LactealsLacteals are lymphatic vessels that are are lymphatic vessels that are

surrounded by capillaries in the core oif the surrounded by capillaries in the core oif the villie that absorb fats which are combined villie that absorb fats which are combined with proteins.with proteins.– These lipid proteins are calledThese lipid proteins are called chylomicrons.chylomicrons.– They travel from through the lyphatic system and They travel from through the lyphatic system and

eventually drain back into the blood and travel to eventually drain back into the blood and travel to the heartthe heart..

Capillaries and veins drain blood into Capillaries and veins drain blood into the the hepatic portal vessel hepatic portal vessel which which carries blood to the liver.carries blood to the liver.– Ensures that the liver has first access to Ensures that the liver has first access to

the nutrients in the blood.the nutrients in the blood.– The nutrient balance of the blood leaving The nutrient balance of the blood leaving

the liver may be very different than it was the liver may be very different than it was when it entered.when it entered.

– One of the many functions the liver include One of the many functions the liver include regulating glucose levels in the blood and regulating glucose levels in the blood and converting amino acids into converting amino acids into carbohydrates.carbohydrates.

– From the liver the blood travels to the From the liver the blood travels to the heart to be pumped to the rest of the body.heart to be pumped to the rest of the body.

Hormonal Regulation of Hormonal Regulation of DigestionDigestion

Hormones released by the stomach and Hormones released by the stomach and duodenal wall ensure that digestive juices duodenal wall ensure that digestive juices are only around when they are needed.are only around when they are needed.

The sight of food will stimulate the brain to The sight of food will stimulate the brain to tell the stomach wall to release tell the stomach wall to release gastrin gastrin which in turn stimulates gastric juices to which in turn stimulates gastric juices to be secreted.be secreted.

Gastric juices cause more gastric juices to Gastric juices cause more gastric juices to be released.be released.

A drop in pH inhibits gastrin.A drop in pH inhibits gastrin.

EnterogastronesEnterogastrones are secreted by the are secreted by the duodenal wall which causes the duodenal wall which causes the duodenal wall to secrete duodenal wall to secrete secretinsecretin whichwhich signals the pancreas to secrete signals the pancreas to secrete bicarbonate to nueteralize chyme as it bicarbonate to nueteralize chyme as it enters the duodenum.enters the duodenum.

Cholecystokinin(CCK)Cholecystokinin(CCK) siganls the siganls the gallbladder to contract and secrete gallbladder to contract and secrete bile into the duodenum when chyme is bile into the duodenum when chyme is rich in fats.rich in fats.

Other enterogasterones restrict Other enterogasterones restrict peristalsis when chyme is rich in fats.peristalsis when chyme is rich in fats.

CATCAT

Reabsorbing WaterReabsorbing Water

Most of the water from waste is Most of the water from waste is absorbed in the absorbed in the coloncolon..

The junction between the duodenum The junction between the duodenum and the colon is called the and the colon is called the CecumCecum..

Humans have a small ceum compared Humans have a small ceum compared to other animals.to other animals.

A fingerlike projection that extends A fingerlike projection that extends from the cecum is called the from the cecum is called the appendix.appendix.

Colon BacteriaColon Bacteria

FloraFlora are bacteria that live within are bacteria that live within the body that are beneficical.the body that are beneficical.

E.Coli live in the colon and produce E.Coli live in the colon and produce vitamins, K B, biotin and folic acid.vitamins, K B, biotin and folic acid.

Generate gases such as methane Generate gases such as methane and hydrogen sulfide as by products and hydrogen sulfide as by products of microbial metabolism.of microbial metabolism.

Structual Adaptations of the Structual Adaptations of the Digestive SystemDigestive System

The type of teeth and the way that they are The type of teeth and the way that they are arranged accommodate an animals’s diet.arranged accommodate an animals’s diet.– Herbivores like horses have flat molars fro Herbivores like horses have flat molars fro

grinding.grinding.– Carnivores have pointed incissors for tearing Carnivores have pointed incissors for tearing

and catching prey.and catching prey.– Carnivores have large expandable stomachs to Carnivores have large expandable stomachs to

allow them to eat large a mounts of food at once allow them to eat large a mounts of food at once because there may be long periods of time because there may be long periods of time where they go without food.where they go without food.

– Snakes have hollow teeth to store venom.Snakes have hollow teeth to store venom.– Snakes have a flexible ligament that allows Snakes have a flexible ligament that allows

them to open their jaw to swallow prey whole.them to open their jaw to swallow prey whole.

Length of Digestive TractLength of Digestive Tract Herbivores and Ominvores have a relatively Herbivores and Ominvores have a relatively

long alimentary cavity relative to their long alimentary cavity relative to their digestive tract because they ingest digestive tract because they ingest cellulose.cellulose.– Hard to digest and low in energy content.Hard to digest and low in energy content.– Many herbivores have symbiotic bacteria living in Many herbivores have symbiotic bacteria living in

specialized organs that digest cellulosespecialized organs that digest cellulose RuminantsRuminants Crop in the Hoatzin(South American Bird from the Rain Crop in the Hoatzin(South American Bird from the Rain

Forest) have bacteria that digest cellulose.Forest) have bacteria that digest cellulose.

– Rabbits eat their feces and digest it again.Rabbits eat their feces and digest it again.– Cows regurgitate and chew their food over again.Cows regurgitate and chew their food over again.

Large Intestine

Termite Triconym and Symbiont