Introduction to Digestion

A 5 We are learning to demonstrate an understanding of animal anatomy and physiology of the digestive system.

Success Criteria: I can…

- use appropriate terminology related to animal anatomy- explain the anatomy of the digestive system

-identify disorders of the digestive system

heterotrophs - organisms that need to eat food to obtain nutrients

(Autotrophs ---> produce their own food) -digestive system breaks down large complex

molecules into smaller components that cell can use

4 stages of digestion:1. ingestion - the taking in of nutrients 2. digestion - breakdown of complex organic

molecules into small components - food molecules must be broken down so they are

small enough to be absorbed into cells!

• mechanical digestion - physically breaking down food stuff

•chemical digestion - breaking the bonds that hold large complex molecules together to smaller components

-enzymes are needed

Vs.

As you watch the short video (made likely before you were born!) watch for information on mechanical and chemical digestion. - How are these two processes the same? different? - What are examples of each?

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Create a VENN diagram to compare mechanical and chemical digestion.

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Both breakdown

food Both part of

digestion

Breaks down food into small pieces of food.

Breaks down food molecules into smaller molecules.

Mechanical Chemical

No enzymes are needed.

Enzymes are needed.

Eg., teeth chewing food in mouth.

Eg., enzyme (amylase) breaking down starch in mouth.

3. absorption - the transport of nutrients into cells (This is why digestion needs to occur first!) 4 egestion - the removal of waste from materials

4 stages of digestion (cont’d):

NOTE: NOT to scale!

Inside of small intestine

Cells lining small intestine (both sides)

Small nutrients being absorbed into cells then into capillaries (not shown).

Digestion in Simpler Organisms

internal digestion • cells engulf food ---> vacuole ---> lysosomes

digest particles (phagocytosis) eg: amoeba

Digestion in More Complex

Organisms

Gastrovascular cavity digestion - Digestive sac with one opening (think about that for a

second!) - Food digests and is absorbed by a cells lining a cavity eg: Hydra

Digestion in more complex Organisms

Gastrointestinal Tract - = (digestive tube) - Mouth --> specialized region for digestion--> anus - humans have a gastrointestinal tract (basically our

digestive system is ‘just’ a tube!)

Assignment

Page 410 # 7, 8, 12, 13,15