Digestion in Other Organisms

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

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

Bird

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

Cow

Digestive System Practice Problems

Page 284 #1-12 inclusive

Due Wednesday!

Reminder: Digestive System Quiz Wednesday!