A Detailed Lesson Plan in Science Grade 8
I.
OBJECTIVES
At the end of the lesson, the students will be able to:
a. Identify the structures of the digestive system;
b. demonstrate an understanding of digestive system functions; and
c. present an analysis of the path of food as it is digested.
II.
SUBJECT MATTER
a. Topic: Structure and Functions of the Digestive System.
b. Reference: (book title, author, pages)
c. Instructional Materials: Pictures, crackers, powerpoint presentation,
whiteboard, fake digestive system statue of the human body.
III.
PROCEDURES
TEACHER’S ACTIVITY
A. Preliminary Activities
Greetings
Prayers
Checking of Attendance
Classroom Management
STUDENTS’ ACTIVITY
(Students are doing the activities)
B. Review
Before we proceed to our lesson, let’s
have a recap from what we have
discussed last meeting.
(Teacher asking students about the
lesson yesterday.)
(Students are doing the recap)
C. Motivation
Ok class, did you have your breakfast?
Who among you here did not have his/her
breakfast?
(Nobody raised their hands)
Are you hungry now?
Yes sir
Before we start our lesson, we will have some
activity.
(Each student will be given 2 crackers)
Activity: CRACKER IN THE MOUTH
Step 1- Put a regular cracker into your
mouth and chew.
Step 2- Place the new cracker in your
mouth and let it sit for 2 mins.
Okay class, what do you observed in our
activity?
What does it feels like initially?
What it feels after 2 minutes in your mouth and
what it feels like when you chew it?
Varied answers of the students
Very good class!
Our activity shows how the saliva in our mouth
lubricates and soften the food we ate.
Are you ready now to our lesson?
Yes sir!
D. Lesson Proper
I’m going to divide you into six groups, choose
one representative in your group and proceed
in front.
Yes sir!
Here are six envelopes then choose one
envelope then proceed to your respective
group.
(6 students will approach the front.)
Now let’s open the envelope then identify the
specific picture and discuss its function in 3
minutes.
Students will return to their group with
the envelope.
Okay, Times Up! What have you noticed about
the pictures?
They are parts of Digestive System.
Yes, very good! And now we will discuss about
the digestive system in detail.
Ok class, do you have any idea about the
Digestive System?
The Digestive system is the one
responsible for the food we eat.
That is correct!
The Digestive System is responsible for the
breakdown and absorption of the nutrients from
the food thereby bringing energy for the body,
and it is divided into two parts the organ of
alimentary tract that comes in contact with the
food and the accessory organ that pour out
secretion to assess in the digestive system.
What is the process by which the food is
broken into smaller components that the body
can absorb to nourish the cell?
Digestion
What are the two phases of Digestion?
Mechanical and Chemical Digestion
During mechanical digestion the food is
broken down into smaller pieces in the process
of chewing or mastication.
Example is the cracker in the mouth activity.
In chemical digestion the food is acted upon
the chemical subs called enzymes. The
enzymes convert the food into their simplest
form.
Ok class, did you understand?
Yes, sir.
Now class, one representative per group will
discuss their collaboration in front.
Yes, sir.
Who among you here have the mouth image?
Be the first to discuss your work.
We have it!
Very good! You may now take your seat.
The mouth is where the digestion
begins, in the mouth the food is
mechanically and chemically digested.
The mouth contains the following structures.
The teeth which breaks down the food into
smaller pieces.
The tongue a muscular organ that mixes the
food with saliva aids in swallowing.
The duct of the salivary glands that secretes
saliva that lubricate the food and the palate
that forms the rooting of the mouth.
What is the enzyme that digest the
carbohydrates in the mouth?
That is correct!
The food that enters the mouth is chewed and it
is now called bolus.
Salivary Amylase Ptyalin
Let’s follow the food as it passes through the
digestive system.
Okay, from the mouth food passes through the
what?
Yes, that’s right, and who have the picture of
the pharynx, can you share your ideas?
Very good!
The pharynx is 5-6 inches long. During
swallowing, the sphincter muscles relaxes and
raise the epiglottis which prevents the bolus or
the food from entering in the trachea.
Pharynx
The pharynx or throat is located
posterior to the mouth, it is the
common passageway for digestion and
respiration.
What prevent the bolus or food from entering
the trachea?
After the food passes through the pharynx the
next is?
Correct! Which group will discuss about the
esophagus?
Epiglottis
Esophagus
Very good! You may return to your seat.
During swallowing, the bolus is conveyed by
the esophagus into the stomach via wavelike
contraction and relaxation of involuntary muscle
that is called peristalsis.
The esophagus is a muscular tube
through where the food s from pharynx
to the stomach.
What is that wavelike contraction or rhythmic
movement?
Through peristalsis, the food goes through the
cardiac sphincter a ring shape muscles,
where food enters from the esophagus to the
stomach to prevent food reflux.
So again, what is the muscles that prevent food
reflux?
That is correct!
Peristalsis
Now, after the food pass through the
esophagus and next is the?
Cardiac Sphincter
Can you discuss it in front?
Stomach
Yes, the stomach is a pear-shaped organ that
is about 30.5 cm long and 15.2 wide, the bolus
enters the stomach will convert to semi fluid
partially digested food, what we called?
The stomach is an expanding organ
located between the esophagus and
small intestine. The stomach stores the
food and mixes the food with gastric
juice.
Very good and now next organ is the small
intestines.
Please go in front and discuss.
Chyme
Yes, good job.
The chyme enters to the small intestines
through the pyloric sphincter, the small
intestine signals the pancreas to produce
pancreatic juice, and the gall bladder to
release bile.
Pancreatic juices aid in the digestion of
protein and carbohydrates and the bile is
responsible to break down fats.
Small intestine is considered as the
organ of complete digestion and
absorption, it is considered as the
longest organ of the digestive system.
Okay class, what organ produces the bile?
What organ stores the bile?
After passing through the small intestine, the
food enters to the?
The last group will share their idea.
Liver
Gall bladder
Large intestine
Very good. The appendix is also located in the
proximal end of the ascending colon.
The undigested residue or the feces it will be
stored in the RECTUM then excrete to the
ANUS.
Large intestine is divided into 3 parts:
ascending colon, transverse colon and
the descending colon. The large
intestine stores the fecal materials,
absorbs the vitamins, and reabsorbs
the water from the undigested residue.
So, in summary class, the digestive system is
composed of the?
What are the accessory organ of digestion?
All are which function to do what?
Mouth, Pharynx, Esophagus, Stomach,
Small intestine, Large intestine,
Rectum and the Anus.
Liver, Gallbladder, Pancreas, Salivary
glands.
Okay class, do you understand?
E. Application
To further understand the lesson, let’s do some
demonstration.
They are responsible for breakdown
and absorption of nutrients from food
thereby bringing energy to the body.
Yes, sir.
We called this BREAD IN THE BAG
Procedures:
1. Take ½ piece of bread per group
2. Obtain the zip lock bag.
3. Tear your ½ sliced of bread into smaller
pieces and placed it into the bag. What
does this represent?
4. Pour smaller amount of water into the
bag. What does this represent?
5. Close the bag and squish the bread with
your finger until all pieces are small.
What does this represent?
6. Drain the liquid contents down to the
sink by creating a small gap which
prevent by escaping. What does this
represent?
7. Put all the content of the bag into the
garbage. What does this represent?
Materials needed are Zip lock bag, ½
sliced bread and water.
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F. Generalization
Okay class. Did you understand our lesson for
today?
IV.
Food broken into smaller pieces
by the teeth. Mechanical
digestion in the mouth.
Food is mixed with gastric juice
of the stomach. Chemical
Digestion in the stomach.
Represent the peristalsis and
mechanical digestion in the
stomach.
Large intestine reabsorbs the
water of undigested residue.
Waste or the feces is temporary
stored in the rectum and it was
excreted in the anus.
Yes sir. (Students are generalizing the
lesson.)
EVALUATION
Identification:
1. The organ that stores and concentrate the bile.
2. The organ of complete digestion and absorption.
3. Where the fecal material exit.
4. The organ produces the bile.
5. It is where the absorption of water takes place.
6. The enzyme that is present in our saliva.
7. The organ where digestion and respiration cross.
8. The process of breaking down the food into simple that the cell can use.
9. Wavelike contraction or rhythmic movement of the involuntary muscle.
10. The organ that temporarily stored the feces.
V.
ASSIGNMENT
Make a research about the different digestive disorder and write it in your assignment
notebook.