6. Inside the Human
Mouth Inside the
Photograph by Lennart Nilsson mouth, shown
magnified
here, teeth, tongue, a
nd saliva work
together to physically
and chemically break
down food.
Humans produce up
to 3 pints (1.4 liters) of
saliva daily, and
chemical enzymes in
the saliva play a major
role in disintegrating
http://science.nationalgeographic.com/science/photos/digesti
ve-system/?source=A-to-Z#/human-mouth_1002_600x450.jpg
starchy foods.
7. NOTES!
We know that M and C digestion
begins in the mouth…
What are the structures in the mouth?
What do they do?
Which structure starts C digestion?
8. NOTES!
What’s happening with your
saliva?
Starch is a long glucose polymer
Enzyme amylase, found in your
saliva, breaks down starch into smaller
glucose units
9. Take notes in your notebook!
Cracker Experiment
Each person gets one cracker.
Break off a small part of your cracker and
place it on the front of your tongue. Leave it
there for at least two minutes!
What does it taste like (bitter, sweet, salty)?
What is happening and why?
Is there a connection between this
experiment and the peristalsis experiment?
10. Brain Pop on the
Digestive System
http://www.brainpop.com/health/bodysystems/digestive
system/preview.weml
13. NOTES!
Your stomach!
Muscular sac where food mixes with gastric
juice (also called stomach acid or
Hydrochloric acid (HCl)).
If HCl is so strong, why doesn’t your stomach
burn from the inside out?
HCl is produced in the stomach lining and
activates the enzyme pepsin which starts
protein digestion.
Does peristalsis occur in the stomach too?
Why or why not?
Discuss with the people at the table in front or
behind you.
14. NOTES!
The Small Intestine
What structures are associated with the
small intestine?
D
L
G
P
What functions of the digestive system do
they support?
15. This colored scanning
micrograph shows a cast
of blood vessels from the
external wall of the small
intestine.
Measuring about 22 feet
(6.7 meters) in
length, the small intestine
performs most of the
major digestion and
absorption of nutrients.
The walls of the small
intestine are lined with
millions of projections
called villi, which absorb
and transmit nutrients
into the bloodstream.
http://science.nationalgeographic.com/science/photos/digestive-
system/?source=A-to-Z#/small-intestine-vessels_1211_600x450.jpg
16. NOTES!
Villi in the small intestine
Bumpy so well suited
for absorption.
Tiny finger shaped
structures increase
surface. They also
absorb nutrient
molecules and pass
them to the blood
vessels.
17. Villi Volunteers
(two different people!)
Compare the two different pieces of fabric.
The one with the finger like pieces is similar to
the villi.
Which fabric will absorb more water? What
do you think?
Each volunteer should submerge their piece
of fabric into the water and hold it for five
seconds.
Bring the fabric out of the water and squeeze
the water into a cylinder.
Which piece of fabric absorbed more water?
19. How do nutrients get to the
rest of the body?
Nutrients pass from the cells of
the villi into the body.
Blood vessels are covered by
a single layer of cells so
nutrients pass through cells
into the blood.
20. Absorption
passage of
molecules
into body's
interior &
passage
throughout
the body
21. Liver and Gall Bladder
Two more volunteers!
Fill two jars half full of
water. Add a few
drops of oil to each jar.
Add ¼ tsp baking soda
to one jar.
Stir contents of both
jars.
Which jar did the oil
begin to break up?
What does the baking
soda represent?
22. NOTES!
Small Intestine
Liver produces bile.
• Bile is a substance (not an enzyme) that breaks up
fat particles into fat droplets and neutralize
stomach acids .
Gall Bladder stores bile.
Pancreas produces enzymes to
chemically breakdown fat droplets.
23. NOTES!
Last but not least…
The Large Intestine
Colon
• Removes waste
and reabsorbs
water and salts
Rectum
• Stores waste.
Anus
• Excretes waste.
Digestion (C and M), Absorption of Nutrients, Excretion of Waste
Structures: teeth cut, grind and chew food; tongue moves food around; and salivary glands begin chemical digestion
Explain how the enzyme, amylase, in your saliva breaks down the carbohydrate into a simple sugar (glucose). What type of digestion is this? Answer: Chemical.
User ID: ismanila; Password: ismanila
Because involuntary muscle contractions of the esophagus PUSH the food to the stomach.
Stomach
Mucus coats and protects the lining of the stomach; Yes peristalsis occurs in the stomach because it is has muscular contractions also which aid in mechanical digestion by churning the food.
Duodenum takes nutrients in to the blood (absorption). Liver, gall bladder and pancreas have enzymes that break down fat (chemical digestion).
