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Digestive system

Content objective:

What are we learning and why are we learning this? Content, procedures, or skills.

Vocabulary objective

Tier II: High frequency words used across content areas. Key to understanding directions & relationships, and for making inferences.

Tier III: Low frequency, domain specific terms.

Building on what we already know

Make connections to prior knowledge. This is where we build from.



teeth mechanically break down food

salivary enzymes chemically break down starch

Salivary amylase enzyme mouth GIF

from dynamicscience.com.au


food doesn’t “fall down” tube due to gravity

muscles squeeze a food bolus down the tube, towards stomach

Esophagus 1

Pearson Education 2004,Biology: Exploring Life

Here we see an animation of the food muscles pushing the bolus down the esophagus.

esophagus 2 GIF


acid kills germs

acid further digests food

Digesting nutrients

Small intestine

more enzymes break larger organic molecules into smaller ones.

now small compounds are absorbed into the blood stream.

Small intestne GIF


The pancreas has two major jobs: Digestion, and hormonal control of blood sugar levels.


The liver has several functions: One of them is being part of the digestive system.
Read more about the liver here.

Large intestine

Anything left over continues into the large intestine.

Excess water is absorbed back into the body in the large intestine.

What is left then is undigested food. This is stored in the rectum, the lower part of the large intestine, until we are ready to go to the toilet.

It then comes out of the rectum through the anus as feces (elimination)

Large Intestine Colon GIF


Letfovers are eliminated (defecation) at your convenience.

Related topics

Probiotics and human health


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