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

• mechanical digestion - physically breaking down food stuff

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

Vs.

3. absorption - the transport of nutrients to tissues – nutrients need to be small enough to be transported

into cells 4 egestion - the removal of waste from materials

– first from individual cells, then from body

4 stages of digestion (cont’d):

Digestion in Simpler Organismsinternal digestion

• cells engulf food ---> vacuole ---> lysosomes digest particles (phagocytosis)

eg: amoeba

Digestion in More Complex

OrganismsGastrovascular cavity digestion - Digestive sac with 1 opening - Food digests and is absorbed by a cells lining a

cavity eg: hydra, planaria

Digestion in more complex Organisms

Gastrointestinal Tract - = (digestive tube) - Mouth --> specialized region for digestion--> anus