1. To :Mr.Gunderpants
From: Kelsey Lalonde
8B Science
January 2009

2. By: Kelsey L. Sarah K. Marvin T. Kyle F. Amber C.
The Digestive System
By: Kelsey L.
Sarah K.
Marvin T.
Kyle F.
Amber C.

3. Structures and Functions
Salivary-Glands
Mouth
Esophagus
Stomach
Liver
Pancreas
Gall Bladder
Small/ Large intestine
Functions:
Breaks down food into much smaller pieces so they can be absorbed and transported throughout the body

4. Types of Digestive Mechanical:
Involves an actual physical breakdown of FOOD into very small pieces
Chemical:
Breaks down larger PARTICLES into small particles by substances called ENZYMES

5. The Mouth and Esophagus
The First Steps of Digestion!
Teeth mechanically digestive your food
Saliva is produced from Salivary Glands (they are located in tissues surrounding the mouth)
Saliva chemically digests your food
- Saliva has water in it to moisten the food
- Saliva also has enzyme which breaks down
molecules (figure 3.3)
The tongue moves the food to the back of your throat
A flap of skin called the epiglottis moves across the windpipe to let food in
Then your muscles in your esophagus contract so food can go down (figure 3.4)

6. The Stomach Your food has now made it to the stomach! Now what?
The stomach has a couple jobs to do
The walls of the stomach which are very muscular churn the food back and forth
The walls of the stomach also releases Gastric Juice which chemically digests food as well
- Gastric Juice contains mucus, hydrochloric acid,
water, and digestive enzymes
(figure 3.6)
Now the food is on its way to the small intestine!

7. The Small intestine, pancreas, Liver, and Gall Bladder
These are the jobs for the lower part of the digestive system
The pancreas sends digestive enzymes into the small intestine
The breakdown of starches and protein into very small particles is complete due to the enzymes that the pancreas sent and the enzymes already in the small intestine
The liver produces bile (a liquid that helps digestion), which is stored in the gall bladder, then is sent to the small intestine
The small intestine absorbs the particles

8. In Addition to the Small Intestine…
Once absorbed the particles, the small intestine forms in villi- small, finger like projections (figure 3.9)
VILLI…
These increase when absorbing nutrients
Each is covered with epithelial tissue
There are blood vessels below the tissue so the nutrients can be absorbed into the blood stream
MICROVILLI
The epithelial tissues have villi as well because the tissue has modified cell membranes

9. These are the last steps!!!!
The Large Intestine
These are the last steps!!!!
By this time, both types of digestion are complete!
The large intestine absorbs water, vitamins, and minerals
Any part of the food that has not been digested are formed into feces and is collected in the rectum

10. PICTURES!!!!
Villi
Stomach
Peristalsis in esophagus

11. Fun Facts
The Small intestine takes about six hours to complete digestion!
Food takes 10 seconds to travel down the esophagus from throat to stomach
Enzymes increase by thousands or millions of times!
The alimentary canal is about 29 feet (9 m) from mouth to anus
There is 4 lbs of friendly bacteria living in your colon
The stomach can increase from 50 ml to 4 LITERS!!!!!!!!
Liver cells are masters at multitasking! The perform more that 500 vital functions like making bile, process, store, and dispatch nutrients and rid the blood of poisonous chemicals
All these facts from the book Dr. Frankenstein's Human Body Book