Digestive System
Lesson 2 – Salivary Glands, Esophagus
Key Words
• Salivary glands: glands in the mouth that make a liquid
called saliva
• Saliva: a liquid made by salivary glands that moisten and
soften food
• Esophagus: a tube leading from the mouth to stomach
• Peristalsis: the action of the muscle in the esophagus
pushing food down to the stomach
• Reverse peristalsis: the action of the muscle in the
esophagus working backwards when stomach rejects
food or liquid
• Hypothesis: a scientific guess based or what you know
Objectives:
• You will be able to name
the parts and function of
the digestive system
• You will use and
understand the scientific
process for groups
experiments
Review
• Let’s review what we know about
taste buds.
• What do taste buds do?
• What are the 5 different tastes we can
detect?
• What is the first part of the digestive
system?
What happens to your food?
• What happens to your food when
you put it in your mouth?
• What happens to your food when
you chew it?
Experiment
• Before scientists perform and experiment they
form a hypothesis ( a guess based on what we
know already).
• A hypothesis is not always correct.
• They are learning tools used to guide us
Experiment 1
• We will be making a hypothesis about what
happens to out food. Go over the experiment
recording sheet.
• You will all receive a soda cracker. You will take one
bite of the cracker and chew it slowly, and then
hold it in your mouth.
What do you think will happen to the cracker?
Write your hypothesis/ prediction for experiment
1
Experiment
Write down what you have
learned from experiment 1.
What observations did you
make?
Experiment 2
• You will all receive another soda
cracker. You lie down on the floor
on your side. You will take one bite
of the cracker and chew it slowly,
hold it in your mouth, the
swallow.
What do you think will happen to
the cracker? Write your
hypothesis/ prediction for
experiment 2
Experiment
Write down what you have
learned from experiment 2.
What observations did you make?
The muscle
is called
Your
food was
did notperistalsis.
stay in your
When you itget
sickpushed
the muscle
esophagus,
was
downwill
by
work
reversetotoyour
cause
vomiting.
the in
muscles
stomach.
This is called reverse peristalsis.
So, now where did your food
travel?
Where might it go next?
Experiment
Use the digestive system diagram
and color in the two steps for the
digestive system.
Your teacher will collect them and
your experiment sheets for later
use.