1. 2.2 THE DIGESTIVE SYSTEM

2. Function
Breaks down food, absorbs nutrients, and eliminates solid waste
The body’s digestive system completes four tasks:
1) Ingestion – take in food
2) Digestion – break food down
3) Absorption – absorb nutrients into bloodstream
4) Elimination – remove waste

3. Anatomy of the Digestive System

4. Digestive Pathway:
mouth
esophagus
stomach
small intestine
large intestine
rectum

5. Mechanical Digestion Chemical Digestion
-food is broken down into smaller pieces
Example:
- Chewing (mouth)
- churning of the stomach to mix food
-substances in our digestive organs are released that change food particles into particles that are chemically different
Example:
-Acids
-Bases
Enzymes (a protein molecule that speeds up chemical reactions)

6. Functions of the Parts
Mouth – mechanical digestion (chewing), produces saliva to moisten food (wet food is called bolus)
Esophagus- pushes food down to the stomach using muscle contractions called peristalsis
Stomach- a muscle that contracts and
relaxes to churn and mix food with acid
Small Intestine- site where most digestion occurs. Food is broken down into tiny nutrients such as sugars, fatty acids and amino acids. These nutrients are then absorbed into the blood stream (capillairies line the outside of this organ to accomplish this).
Large Intestine – absorbs water
Rectum - stores feces (waste) until it is ready to be eliminated

7. Helper Glands Pancreas
-secretes a base into the small intestine to neutralize the acid in the food coming from the stomach
-helps to digests fats and carbohydrates
Liver
-makes bile that breaks down fats
Gall Bladder
-small pouch under the liver that stores extra bile
Salivary Glands
-found in the mouth and create saliva that breaks down carbohydrates

8. What is a FART?????????
A release of methane gas created by bacteria that help to digest your food
You release approximately 100L of gas each year!!!!!!!

9. Cellular Respiration
Sugar (glucose) made during the digestion of your food can’t be used directly by your cells….it must be converted!
Glucose reacts with oxygen from your respiratory system to make energy for your cells in the form of ATP as well as carbon dioxide and water

10. Homework:
What is the difference between mechanical and chemical digestion?
What four tasks must the digestive system complete? List the organs that are responsible for each task.
a) what parts of the digestive system are involved in mechanical digestion?
b) What parts of the digestive system are involved in chemical digestion?
4. Explain how food is pushed down the esophagus
5. What are the helper glands that assist the digestive system?
6. What is cellular respiration?
7. How does the circulatory system, respiratory system and digestive system work together?