1. Digestion in Other Organisms

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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

8. Bird

9. 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

10. 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

11. Cow

12. Digestive System Practice Problems
Page 284 #1-12 inclusive
Due Wednesday!
Reminder: Digestive System Quiz Wednesday!