1. Physical and Chemical Changes in the Digestive System Notes
EQ: What type of change occurs at each of the 7 main digestive organs?

2. Real Life Video of the Digestive System
Inside the System
Length: 5 min and 7 seconds
You have to put this slide into slide show mode to click on the link shown.
You will need headphones for this.
There is nothing you need to write down during the video.

3. Color code the organs in the main digestive tract
Color code the organs in the main digestive tract. Your colors do not need to match these.

4. 4 Functions of the Digestive System
Highlight the 4 functions
Ingestion = Food enters the mouth 1.
Digestion = Process that
breaks food down into small molecules
Mechanical (physical) digestion:
Changes size and shape only
Chemical digestion:
Breaks down large food molecules
into NEW smaller molecules
(Ex: Carbohydrates  Glucose) 2.
Digestion

5. unabsorbed molecules are removed from the body.
Absorption =
Small molecules of food are absorbed by the villi in the small intestine and are transferred to the blood to be delivered to the body’s cells. 3. 4.
Elimination =
Wastes made of
unabsorbed molecules are removed from the body.
Absorption
Elimination

6. Read Only
Click to watch villi absorbtion
Absorption
This shows how large molecules like starches must be broken down into smaller sugar molecules. These molecules then pass through the villi which are the finger-like projections in the small intestines that absorb the nutrients into the blood.
villi

7. Physical/ Mechanical Changes
Write the title shown below in blue. All physical changes that occur in the digestive system will be also be written in blue to color code the notes.
Physical/ Mechanical Changes
The APPEARANCE of the substance alters (changes) NOT their chemical composition!
Change in size or shape
Change in the state of matter (solid, liquid, gas)

8. Write the title shown below in red
Write the title shown below in red. All chemical changes that occur in the digestive system will be also be written in red to color code the notes.
Chemical Changes
These changes alter the substance so that a new substance with NEW properties appears and is NOT reversible:
Unexpected color change or odor
Release of heat, light, or sound
Produces gas (bubbles), or forms a solid substance

9. 7 Major Organs of the Digestive Tract
Write this section title and draw a box around it to make it stand out in your notes. 1.
Mouth
The teeth mechanically tear, rip, and grind the food into smaller pieces.
The tongue pushes the food towards the teeth to be chewed.
Enzymes in the saliva chemically digests food.
When swallowing, the epiglottis (a small flap of tissue) automatically closes over the trachea (windpipe) to avoid food “going down the wrong tube”
Red shows passage of air
Green shows passage of food
Put the PPT into slide show mode to view the above animation

10. Creation of new substance = chemical change
Enzyme: substance that speeds up the breakdown of food by causing a chemical change in which a new substance is created.
Anywhere in the digestive system that a chemical change takes place enzymes are at work.
Draw and label everything shown in this picture.
Carbohydrate
Simple Sugar
Creation of new substance = chemical change

11. Starch breaking down into smaller sugars
Read Only
(Starch)
Digestive
enzymes
Starch breaking down into smaller sugars
Glucose molecules

12. Esophagus
Peristalsis (rhythmic smooth muscular contractions) squeezes the bolus (a mass of chewed food) downward from the mouth into the stomach. 2.

13. Stomach
The stomach is a smooth muscle that contracts and relaxes through peristalsis which squeezes and churns (mixes) the bolus breaking down the size of the ingested materials
Stomach acid (hydrochloric acid) contains enzymes which chemically break the bolus down further forming chyme. 3.

14. What happens to food inside the stomach?
Read Only

15. Accessory Organs- organs that help digestion by producing chemicals but do not actually touch the food.
Liver: Bile (chemical digestive juice) is produced here (Bile breaks down fats like dish detergent breaks down grease.)
Gall Bladder: Bile is stored here until released into the beginning of the small intestine.
Pancreas: Produces pancreatic juices that are released into the beginning of the small intestine to break down proteins, starches, and fats.
The bile and pancreatic juice are secreted into the very beginning of the small intestine which is called the Duodenum.

16. Draw a bubble around the notes about Accessory Organs as shown below.
Then, lightly shade the background of that bubble with your pencil.
The reason it is being shaded is to make it stand out; this is because these organs are not part of the main digestive tract which is what the rest of your notes are about. On the other hand, they play a role in digestion in the small intestine which is why we are writing those notes in that location.

17. Click HERE for enzyme video
You will need headphones.
The PPT must be in full screen Slide Shown Mode to access the link above.

18. Small Intestine
The bile and pancreatic juice are secreted into the very beginning of the small intestine (the Duodenum.) These digestive juices are the final digestive stage in breaking down remaining large molecules.
Nutrients from the chyme (digested food) are absorbed through the villi and enter into the bloodstream. The blood then delivers the nutrients to the body’s cells. 4.
(Longest digestive organ:20 feet long!)

19. 5. Large Intestine (aka: colon)
Since all nutrients were absorbed in the small intestine, the remaining material is called feces, but these wastes are very watery.
The feces spend 18–24 hours in the large intestine. During this time, most of the water is absorbed into the blood stream.
Materials not absorbed form into solid waste.
appendix
This box is READ ONLY:
Feces is composed of dead bacteria, some fat and protein, undigested food, dried out parts of digestive juices, and old intestinal cells.

20. 6.
Rectum
Solid waste passes into the rectum which stores the solid waste until it is ready to be eliminated.
The anus is the opening through which solid waste is expelled out the body. 7.
Anus

21. Read Only
Did you notice….?
“Food” is not called “food” the entire time it is in your body. Since physical and chemical changes are happening to the food throughout the digestive system, its name changes as it travels. Chewed food, once swallowed, becomes a bolus. The bolus becomes chyme when it mixes with the stomach acid in the stomach. When the nutrients are absorbed from the chyme in the small intestine, it then becomes watery feces. The watery feces dries out in the large intestines forming solid feces.

22. Review: READ ONLY Saliva dissolves starch into sugars Teeth chew food
Digestive juices from the accessory organs (liver, gallbladder, and pancreas) are released into the beginning of the small intestine
Peristalsis pushes the bolus down the esophagus
Contractions of the stomach muscles squeeze the chyme
Stomach acid chemically breaks down
the chyme
Nutrients are absorbed by the villi in the small intestine
The solid waste is stored in the rectum
Water is squeezed from the large intestine to solidify the waste
Review: READ ONLY
The solid waste is released through the anus

23. ASSIGNMENT
Create a double bubble comparing physical digestion and chemical digestion.
This is NOT the exact number of bubbles you should have. This picture is just to remind you what a double bubble looks like.
Do NOT pre-draw the bubbles and then fill them in. Instead, draw a new bubble for each new detail you come up with.
Physical Digestion
Chemical Digestion