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Digestion in Other Organisms. Week outline:. Monday: Digestion in Other Organisms Tuesday: Science Center & Body Worlds – have Fun! Wednesday: Digestive System Quiz Digestive System Problems Due (Page 284 #1-11 inclusive) Med School 101 Start Respiratory System
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Week outline: • Monday: Digestion in Other Organisms • Tuesday: Science Center & Body Worlds – have Fun! • Wednesday: • Digestive System Quiz • Digestive System Problems Due (Page 284 #1-11 inclusive) • Med School 101 • Start Respiratory System • Thursday: Respiratory System • Friday: Respiratory System in Other Organisms
Amoeba • One-celled organism • Does not have complex digestive system • Uses phagocytosis for engulfing and ingesting food • Requires energy from ATP • Surrounds food by extensions of cytoplasm called pseudopods • Once inside food is stored in a vacuole
Amoeba • Food vacuoles move with the amoeba • Enzymes that break down food are released into the vacuole • Specific pH within vacuole allows enzymes to work at optimum
Earthworm • Regions in their alimentary canal differ by function • Worms burrow in ground – use prostomium to scoop soil • Muscular pharynx sucks soil into mouth • Nutrient-containing soil passes down esophagus
Earthworm • Nutrient rich soil is stored and moistened in the crop • No teeth – muscular gizzard: equipped with sand and gravel to help allow food from crop to enter (mechanical) • Organic matter is chemically digested & nutrients are absorbed • Indigestible material is eliminated through the anus
Bird • Have alimentary canal similar to worm • Able to eat a variety of food: insects, worms, berries, seeds • Have a crop for storing food • Have a gizzard for mechanically digesting food • Gravel in gizzard help grind food into digestible pieces • Chemical digestion in the stomach • Nutrients absorbed in the intestine
Cow • Ruminant mammals (cows, sheep, deer, etc) have more complex digestive system • 4 chambers • Because they digest cellulose (substance undigested by humans) • Cow chews & swallows mouthful of grass then food enters the rumen • Later travels into the reticulum
Cow • Bacteria in rumen and reticulum start to break down cellulose • Cow helps this process by regurgitating and re-chewing food from time to time • “Rumination” or “chewing of the cud” – softens & helps break down plant fibers, making them more accessible to bacteria and more digestible
Digestive System Practice Problems • Page 284 #1-12 inclusive • Due Wednesday! • Reminder: Digestive System Quiz Wednesday!