8
SCIENCE
Quarter 4 - Module 1
Focus on the Digestive System
Science — Grade 8
Alternative Delivery Mode
Quarter 4 – Module 1: Focus on the Digestive System
First Edition, 2020
Republic Act 8293, section 176 states that: No copyright shall subsist in any work
of the Government of the Philippines. However, prior approval of the government agency
or office wherein the work is created shall be necessary for exploitation of such work for
profit. Such agency or office may, among other things, impose as a condition the
payment of royalties.
Borrowed materials (i.e., songs, stories, poems, pictures, photos, brand names,
trademarks, etc.) included in this book are owned by their respective copyright holders.
Every effort has been exerted to locate and seek permission to use these materials from
their respective copyright owners. The publisher and authors do not represent nor claim
ownership over them.
Published by the Department of Education – Division of Gingoog City
Division Superintendent: Jesnar Dems S. Torres, PhD, CESO VI
Development Team of the Module
Writer(s):
Christy Rose G. Velasco
Reviewer(s):
Nilda U. Villegas, EPS – Science
Florida D. Arias, PhD, PSDS
Melinda R. Garabato, PhD
Illustrator(s):
Jay Michael D. Calipusan, PDO II
Layout Artist:
Virra Jill V. Durado
Management Team
Chairperson:
Jesnar Dems S. Torres, PhD, CESO VI
Schools Division Superintendent
Co-Chairperson:
Conniebel C. Nistal, PhD
Assistant Schools Division Superintendent
Pablito B. Altubar
CID Chief
Members:
Nilda U. Villegas, EPS – Science
Himaya B. Sinatao, LRMS Manager
Jay Michael A. Calipusan, PDO II
Mercy M. Caharian, Librarian II
Printed in the Philippines by
Department of Education – Division of Gingoog City
Office Address:
Telefax:
E-mail Address:
Brgy. 23, National Highway, Gingoog City
088-328-0108 / 088 328-0118
gingoog.city@deped.gov.ph
8
SCIENCE
Quarter 4 - Module 1
Focus on the Digestive System
This page is intentionally blank.
Table of Contents
What This Module is About ......................................................................................................... i
What I Need to Know .................................................................................................................. i
How to Learn from this Module .................................................................................................. ii
Icons of this Module ................................................................................................................... ii
What I Know (Pre-Test) ............................................................................................................ iii
Ingestion..................................................................................................................................... 1
What’s In .................................................................................................................................... 1
Activity 1: Word Search .......................................................................................................... 1
What I Need to Know ................................................................................................................. 1
What’s New ................................................................................................................................ 2
Activity 2: Banana (Saba) ...................................................................................................... 2
What Is It .................................................................................................................................... 3
What’s More ............................................................................................................................... 4
Activity 3: Complete the Concept Map................................................................................... 4
What I Have Learned ................................................................................................................. 4
Activity 4: My Realization ....................................................................................................... 4
What I Can Do ........................................................................................................................... 5
Activity 5: Draw and Explain .................................................................................................. 5
Absorption .................................................................................................................................. 6
What’s In .................................................................................................................................... 6
Activity 1. Fill Me .................................................................................................................... 6
What I Need to Know ................................................................................................................. 6
What’s New ................................................................................................................................ 6
Activity 2. Absorption .............................................................................................................. 6
What Is It .................................................................................................................................... 7
What’s More ............................................................................................................................... 8
Activity 3. Complete the Concept Map................................................................................... 8
What I Have Learned ................................................................................................................. 8
Activity 4. My Realization ....................................................................................................... 8
What I Can Do ........................................................................................................................... 8
Activity 5. Brief Explanation ................................................................................................... 8
Assimilation ................................................................................................................................ 9
What’s In .................................................................................................................................... 9
Activity 1. Fill Me .................................................................................................................... 9
What I Need to Know ................................................................................................................. 9
What’s New ................................................................................................................................ 9
Activity 2. Complete the Map ................................................................................................. 9
What Is It .................................................................................................................................. 10
What’s More ............................................................................................................................. 11
Activity 3. Tell Me ................................................................................................................. 11
What I Have Learned ............................................................................................................... 11
Activity 4. My Realization ..................................................................................................... 11
What I Can Do ......................................................................................................................... 11
Activity 5. Brief Explanation ................................................................................................. 11
Excretion .................................................................................................................................. 12
What’s In .................................................................................................................................. 12
Activity 1. Fill Me .................................................................................................................. 12
What I Need to Know ............................................................................................................... 12
What’s New .............................................................................................................................. 12
Activity 2. Food in the Stocking ............................................................................................ 12
What Is It .................................................................................................................................. 13
What’s More ............................................................................................................................. 14
Activity 3. Tell Me ................................................................................................................. 14
What I Have Learned ............................................................................................................... 14
Activity 4. My Realization ..................................................................................................... 14
What I Can Do ......................................................................................................................... 14
Activity 5. Question and Answer .......................................................................................... 14
Diseases of the Digestive System, Treatment, and Prevention ............................................. 15
What’s In .................................................................................................................................. 15
Activity 1. Choose the Right Word ....................................................................................... 15
What I Need to Know ............................................................................................................... 15
What’s New .............................................................................................................................. 16
Activity 2. The Possible Ways .............................................................................................. 16
What Is It .................................................................................................................................. 16
What’s More ............................................................................................................................. 18
Activity 3. Complete Me ....................................................................................................... 18
What I Have Learned ............................................................................................................... 19
Activity 4. Tell Me ................................................................................................................. 19
What I Can Do ......................................................................................................................... 19
Activity 5. Question and Answer .......................................................................................... 19
Summary .................................................................................................................................. 20
Assessment (Post-Test) .......................................................................................................... 21
Key to Answers ........................................................................................................................ 23
References ............................................................................................................................... 28
This page is intentionally blank.
What This Module is About
Food is an essential part of our daily routine. This makes the digestive system our
favorite system. But, have you ever wondered where does the food you eat goes? How the
digestion process occurred?
This module is written for you to have a deeper understanding on the processes of the
digestive system and how it works together with the others systems in our body. This module
also explains the common diseases/disorders of the digestive system and how it can be
treated.
This module contains varied activities which will supplement your learning about the
process of the digestive system which is good for two weeks.
Enjoy learning.
What I Need to Know
After going through this module, you should be able to:
1. Explain ingestion, absorption, assimilation, and excretion.
2. Explain how diseases of the digestive system are prevented, detected, and treated.
i
How to Learn from this Module
To achieve the objectives cited above, you are to do the following:
• Take your time reading the lessons carefully.
• Follow the directions and/or instructions in the activities and exercises diligently.
• Answer all the given tests and exercises.
Icons of this Module
What I Need
to Know
This part contains learning objectives that are
set for you to learn as you go along the module.
What I Know
This is an assessment as to your level of
knowledge to the subject matter at hand, meant
specifically to gauge prior related knowledge.
What’s In
This part connects previous lesson with that of
the current one.
What’s New
An introduction of the new lesson through
various activities, before it will be presented to
you.
What Is It
These are discussions of the activities as a way
to deepen your discovery and understanding of
the concept.
What’s More
These are follow-up activities that are intended
for you to practice further in order to master the
competencies.
What I Have
Learned
Activities designed to process what you have
learned from the lesson.
What I Can
Do
These are tasks that are designed to showcase
your skills and knowledge gained, and applied
into real-life concerns and situations.
ii
What I Know (Pre-Test)
Directions: Choose the letter of the best answer. Write the chosen letter on a separate sheet
of paper.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Which of the following refers to chemical digestion?
A. Chewing of food
C. Tearing of food
B. Grinding of food
D. Amylase in the saliva
In what organ most of the absorption process happen?
A. Stomach
C. Large intestine
B. Small intestine
D. Esophagus
It is a digestive disorder wherein the body has the inability to digest sugar?
A. Gastritis
C. Diarrhea
B. Lactose intolerance
D. Peptic ulcer
The following are part of the digestion process EXCEPT ______.
A. ingestion
C. excretion
B. assimilation
D. respiration
It helps to moisten the food and contains the enzyme amylase.
A. Saliva
C. Mouth
B. Stomach
D. Teeth
It is a process of taking in digested food nutrients into the cell by providing new
protoplasm and energy needed during the cell activities.
A. Ingestion
C. Absorption
B. assimilation
D. Excretion
What causes constipation?
A. Lack of fiber in the body
B. Uncontrolled growth of abnormal cells
C. Lack of enzyme lactase
D. Excessive consumption of coffee and acidic drinks
The nutrients from the digested food are being absorbed by the following processes
except ______.
A. passive diffusion
C. active transport
B. facilitated diffusion
D. ingestion
It is the organ that is responsible for reabsorbing water and minerals that are not
digested in the small intestine.
A. Stomach
C. Small intestine
B. Large intestine
D. Esophagus
The following are the reasons why digested food should be assimilated into the cell
EXCEPT _____.
A. they are converted into protoplasm.
B. they are needed to store fats.
C. they provide energy needed in cell activities
D. they are converted to build cell membranes
iii
Lesson
Ingestion
1
What’s In
Activity 1: Word Search
Directions: Find the needed word below by encircling in the puzzle and fill in the blanks to
complete the statement.
1. The ____________________ takes what the small intestine cannot absorb.
2. The ______________ is a J-shaped sac that stores food.
3. The digestion process starts when we put food in our ________.
4. The ________________ is a long tube that serves as a passage way of food from the
throat to the stomach.
The ___________ helps in chewing and grinding the food inside the mouth.
O
N
E
W
M
I
N
H
O
K
E
Y
S
T
S
T
A
E
M
I
N
D
S
U
H
O
C
M
E
H
L
A
R
G
E
I
N
T
E
S
T
I
N
E
I
E
X
O
K
A
I
D
O
C
H
E
N
J
T
N
S
E
H
U
N
L
O
M
O
U
T
H
Y
H
E
Y
G
E
S
O
P
H
A
G
U
S
B
P
C
E
B
A
E
K
H
Y
N
C
E
X
O
L
K
M
N
X
I
U
M
I
N
C
H
A
N
Y
E
O
L
O
What I Need to Know
Objective:
At the end of the lesson, you will be able to explain the process of ingestion.
1
What’s New
Activity 2: Banana (Saba)
Objective: After performing this activity, you should be able to explain the process of
ingestion.
Materials:
1 Ziplock bag or cellphone bag
2 pieces of banana (saba)
Scissors
Water
Procedure:
1. Prepare the materials needed.
2. Using the scissors, slice the banana and put it in the Ziplock/cellophane bag. Tightly
close the bag and squeeze it. Observe what happen to slices of banana.
3. Put a small amount of water inside the Ziplock bag and tightly close it.
(NOTE: Make sure that the Ziplock bag has no holes).
4. Try to squeeze the Ziplock bag. Observe what happen to the slices of banana.
5. Fill in the table with your observation what happen to the slices of banana and bread
when you squeeze it.
Observation
Physical changes of the slices of banana
when squeezed.
Physical changes of the slices of banana
when you add water and squeezed again
1)
2)
3)
4)
Guide Questions
What does the Ziplock/ cellophane bag represent? How about the water and scissors?
___________________________________________________
___________________________________________________
What does your set of teeth do? Do your teeth perform mechanical or chemical digestion?
___________________________________________________
___________________________________________________
What is the role of saliva in breaking down of food?
___________________________________________________
___________________________________________________
How does the mouth, teeth, saliva, and tongue work together?
___________________________________________________
___________________________________________________
2
What Is It
Digestive system is the system responsible for breaking down food particles and give
nutrients to the different parts of the body. It is a complex process of turning the food you eat
into nutrients which our body uses for energy, growth, and cell repair needed to survive. There
are four stages of digestion namely the ingestion, digestion, absorption, and excretion.
Digestion of food is carried out by the organs and substances of the digestive system.
. The moment you put food in your mouth, the digestion process begins. The first step
of the digestion process is Ingestion. It refers to the entry of food into the alimentary canal
through the mouth. When food is ingested into your mouth, your teeth, tongue, and saliva work
together to begin the process of digestion.
In the activity 1, the Ziplock/cellophane bag serves as the mouth where you put all the
food you eat. Digestion process begins when you put food in your mouth. Our teeth help in
breaking down food by grinding and chewing the large chunks of food into small pieces. In the
activity, the scissors serve as the teeth which was used in cutting the banana (saba) into small
pieces. The cutting or breaking down of food by tearing, grinding, and chewing is what we call
mechanical digestion. The water you added on the activity serves as the saliva. It helps to
moisten food and contains the digestive enzyme amylase. The presence of saliva in the
ingestion process starts the second type of digestion which is chemical digestion. The enzyme
amylase is essential for breaking down starches into sugar. The food mixed with saliva that
forms into a ball inside your mouth is called bolus. After the initial digestion of food, your
tongue helps in pushing the bolus by swallowing the food to throat and into the opening of
esophagus.
3
What’s More
Activity 3: Complete the Concept Map
Directions: Using the concept map, explain the process of ingestion .
Ingestion
What I Have Learned
Activity 4: My Realization
Directions: Write a short essay about the process of ingestion. Your output will be graded
using this rubric.
Criteria
5
Content
Well accurate use of
correct information
about the topic
Organization
of thoughts
Well organized
details about the
topic
3
Somewhat accurate
use of the accurate
information about the
topic
Somewhat organized
details about the topic
4
2
Lack use of the
accurate
information about
the topic.
Poor organization
of thoughts about
the topic.
What I Can Do
Activity 5: Draw and Explain
Direction: Draw and explain the process of ingestion. Write your answer in your notebook.
5
Lesson
2
Absorption
What’s In
Activity 1. Fill Me
Directions: Write the correct answer on the blank to complete the passage.
_______(1)_________ refers to the entry of food into the alimentary canal through the
mouth. When food is ingested into the mouth, the _______(2)________, ______(3)_______,
and saliva work together to begin the process of ________(4)_______.
What I Need to Know
Objective: At the end of the lesson, you will be able to explain the process of absorption.
What’s New
Activity 2. Absorption
Objective: After performing this activity, you should be able to explain the process of
absorption.
Materials:
 1 old sock (if not available you may use ‘lampin’
 Rubber band
 3 pieces of biscuits (if not available you may opt for bread)
 Dipper (kabo) if
not available use
 Water
a basin (balde)
6
Procedure:
1) Prepare the materials needed.
2) Cut the biscuits into small pieces and put it in the bowl.
3) Add small amount of water in the bowl and squeeze the biscuits till it is almost in its
paste form.
4) Use a scissor and divide the stockings into several pieces for future use. Make use of
a rubber band and tie one end of the stocking.
5) Pour the paste form of the ‘digested food’ in the bowl into the socks/lampin.
6) Using your hands, try to squeeze the stockings and get as much water as you can
out from the ‘digested food’. Put the excess water in a dipper. Observe.
Guide Questions
1) What does the stockings represent?
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
2) What happen to the digested food in the small intestine?
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
3) How does the process of absorption happen in the small intestine?
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
What Is It
Absorption is a complex process that happens in the small intestine. 90% of ingested
water, vitamins, minerals, carbohydrates, proteins, and lipids are absorb by the small intestine.
In the activity, the socks or lampin serves as the small intestine. The cloth of the socks/lampin
help in absorbing the excess water from the digested food. The cloth of the socks/lampin
serves like the lining of the intestine walls which are the finger-like projections called villi.
These villi are covered in microvilli which further increases surface area for absorption. The
presence of villi and microvilli in the intestine walls plays a big role in the absorption process
of nutrients in the food. The process of absorption in the small intestine begin once the
digested food from the stomach moves in the small intestine. The nutrients from the digested
food are absorbed by the inner walls of the small intestine into the blood stream. Because the
nutrients are small enough, they may pass or be transported across the epithelial cells of the
gastrointestinal tract. The nutrients are absorbed by processes of passive diffusion, facilitated
diffusion, and active transport. The process of absorption is very important because through
this process we can get the nutrients out from the food we eat and will be further use by the
cells throughout our body.
7
What’s More
Activity 3. Complete the Concept Map
Directions: Using the concept map, explain the process of absorption.
Absorption
What I Have Learned
Activity 4. My Realization
Directions: Write a short essay on your learning on the process of absorption.
Criteria
Content
Organization
of thoughts
5
Well accurate use of
correct information
about the topic
Well organized details
about the topic
3
Somewhat accurate use of
the accurate information
about the topic
Somewhat organized
details about the topic
2
Lack use of the
accurate information
about the topic.
Poor organization of
thoughts about the
topic.
What I Can Do
Activity 5. Brief Explanation
Direction: On your activity notebook, write a brief explanation about the importance of
absorption in the process of digestion.
Criteria
Content
Organization
of thoughts
5
Well accurate use of
correct information
about the topic
Well organized details
about the topic
3
Somewhat accurate use of
the accurate information
about the topic
Somewhat organized
details about the topic
8
2
Lack use of the
accurate information
about the topic.
Poor organization of
thoughts about the
topic.
Lesson
3
Assimilation
What’s In
Activity 1. Fill Me
Directions: Complete the passage with the correct answer. Write your answers on the space
provided.
___(1)____ is a complex process in which the nutrients from the digested food are
being absorb and distributed into the bloodstream. Most of the absorption process happens in
the _____(2)________. It has __(3)____ and ____(4)____ in the intestine walls is a big help
in the absorption process.
What I Need to Know
Objective: At the end of the lesson, you will be able to explain the process of assimilation.
What’s New
Activity 2. Complete the Map
Directions: Complete the concept map on what happen to the digested food after absorption,
and write your answer in your activity notebook.
What happen to
the digested food
after absorption?
9
What Is It
Assimilation is a process of taking in digested food nutrients into the cell by providing
materials in building new protoplasm and energy needed during the cell activities. This process
occurs in the small intestine. Assimilation simply means resynthesizing or putting back
together all those molecules to form a bigger formation of proteins, polypeptides,
carbohydrates, and lipids. After the absorption process, the digested food products such as
the glucose, amino acids, and fatty acids are in the bloodstream. These nutrients should be
delivered in the cell. The digested food products should be assimilated into the cell because
of the following reasons;
 They provide energy needed in cell activities like for example the glucose is
needed in respiration to form ATP and amino acids are used to build new proteins.
 They are converted into protoplasm.
 They are converted to build cell membranes for example the fats are needed for
the formation of the cell membranes.
The end product of carbohydrate breakdown (glucose) reach the liver by hepatic portal
veins. Inside the liver, the excess of glucose is converted into glycogen. The amino acids also
reach the hepatic portal veins where amino acids get breakdown. Separated amino acids are
converted into urea with the carbon dioxide. These are excreted in our body in the form of
urine. The fats are stored in liver, bone, and adipose tissue like our thighs. Some fats also
enter into the composition of cell organelles.
Assimilation basically means storing nutrients when they are not yet needed and reuse
them whenever they will be required.
10
What’s More
Activity 3. Tell Me
Directions: Explain where the nutrients will be assimilated.
1. Carbohydrates
___________________________________________________________________
___________________________________________________________________
2. Fats
___________________________________________________________________
___________________________________________________________________
3. Amino Acids
___________________________________________________________________
___________________________________________________________________
What I Have Learned
Activity 4. My Realization
Directions: Write a short essay on your learning on the process of assimilation.
Criteria
Content
Organization
of thoughts
5
Well accurate use of
correct information
about the topic
Well organized details
about the topic
3
Somewhat accurate use of
the accurate information
about the topic
Somewhat organized
details about the topic
2
Lack use of the
accurate information
about the topic.
Poor organization of
thoughts about the
topic.
What I Can Do
Activity 5. Brief Explanation
Direction: On your activity notebook, write a brief explanation about the importance of
assimilation in the process of digestion.
11
Lesson
4
Excretion
What’s In
Activity 1. Fill Me
Directions: Complete the passage with the correct answer. Write your answers on the space
provided.
_________(1)_________ is a process of taking in digested food nutrients into the cell
by providing materials in building new protoplasm and energy needed during the cell activities.
After the absorption process, the digested food products such as the glucose, amino acids,
and fatty acids are in the _______(2)_________. This process basically means
_______(3)_____________ when they are not yet needed and reuse them whenever they will
be required.
What I Need to Know
Objective: At the end of the lesson, you will be able to explain the process of excretion.
What’s New
Activity 2. Food in the Stocking
Objective: After performing this activity, you should be able to explain the process of
excretion.
Materials:
 1 old stockings/socks
 Small bowl
 Digested food (See activity 2 in Lesson 1)
 Dipper (kabo) if
not available use
 Water
a basin (balde)
12
Procedure:
1.
2.
3.
4.
Put the digested food in the stocking.
Squeeze the stockings to get all the excess water.
Push the solid residue out from the stockings.
Observe what happen to the solid residue.
Guide Questions
1) What does the stockings with the undigested food represent?
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
2) How does the process of excretion happen?
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
What Is It
Excretion is the process of removing wastes and excess water from the body. The
excretion in the digestive system works with the excretory system to excrete or eliminate the
waste product of our body. After the absorption and assimilation process that happens in the
small intestine, the undigested materials move to the large intestine. In activity 2, the stocking
serves as the large intestine. It is responsible of reabsorbing the water and minerals that are
not digested in the small intestine. The rest of the undigested materials move to the rectum
until they are eliminated from the body through the anus. The process of excretion is very
important for our body to maintain homeostasis in our body. The waste by-product of our body
should be eliminated for us not be intoxicated and may lead to serious diseases or health
problems. Drinking lots of water is a big help in the easy and smooth elimination of feces in
our body.
13
What’s More
Activity 3. Tell Me
Directions: Explain the excretion that happen in the large intestine.
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
What I Have Learned
Activity 4. My Realization
Directions: Write a short essay about the process of excretion in the digestive system.
Criteria
Content
Organization
of thoughts
5
Well accurate use of
correct information
about the topic
Well organized details
about the topic
3
Somewhat accurate use of
the accurate information
about the topic
Somewhat organized
details about the topic
2
Lack use of the
accurate information
about the topic.
Poor organization of
thoughts about the
topic.
What I Can Do
Activity 5. Question and Answer
Direction: Explain briefly and write your answer in your notebook.
1. Why the excretion process is important?
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
14
Lesson
5
Diseases of the Digestive System,
Treatment, and Prevention
What’s In
Activity 1. Choose the Right Word
Directions: Identify the word that is being described in each statement. Choose your answers
in the box below. Write your answers in your notebook.
___________________
___________________
1.
2.
___________________
___________________
3.
4.
___________________
5.
Small intestine
Colon
It is where most of the absorption process happen.
It is a process of taking in digested food nutrients into the
cell by providing materials in building new protoplasm and
energy needed during cell activities.
It is where ingestion process begins.
It helps to moisten the food and contains the enzyme
amylase.
It is the organ that reabsorbs vitamins and minerals which
are not absorbed by the small intestine.
Stomach
Saliva
Assimilation
Mouth
What I Need to Know
Objective: At the end of the lesson, you will be able to explain how diseases of the digestive
system are detected, treated, and prevented.
15
What’s New
Activity 2. The Possible Ways
Directions: Please complete the table below. Write the symptoms and possible treatment you
know about the common digestive diseases.
Common Digestive
Diseases/Disorders
What did you feel when you
experienced that
disease/disorder?
What did you do to ease
the uncomfortable
feeling you had?
Peptic Ulcer
Diarrhea
Constipation
What Is It
The following are the common diseases that affect the digestive system:
 Gastroesophageal Reflux Disease (GERD) – it is commonly called ‘severe
heartburn’ or a burning pain in your chest. It is a disease in which the ingested food
leaks back from the stomach into the esophagus. The stomach acid that flows back
irritate and inflame the lining of the esophagus. The person who experiences GERD
has a difficulty in swallowing and reflux.
 Treatment/ prevention – elevation of the upper body is highly recommended
when. Avoid eating chocolates, spicy foods, alcoholic drinks, coffee, and fatty
foods. Doctors also recommend to take antacids an hour after meals to
neutralize the acidity in the stomach and avoid lying down after a meal.
 Gastritis - it is the inflammation of the stomach caused by too much intake of
alcoholic drinks, coffee, or any acidic drinks, stress, smoking cigarettes, and the too
much intake of anti-inflammatory drugs such as the aspirin and ibuprofen. Nausea,
upset stomach, vomiting, indigestion, abdominal pain, loss of appetite are some
symptoms of gastritis.
 Treatment/prevention – gastritis can be treated by changing one’s lifestyle or
if it is caused by an infection, taking antibiotics which, your doctor prescribed
can be an option too. Avoid drinking acidic drinks such as alcohol and
minimize coffee intake.
 Peptic Ulcer – it is painful sores that develop in the lining of stomach or small
intestine. It is caused by the bacteria H.pylori and also too much intake of acidic
drinks such as alcohol. Nausea, feeling abdominal pain or burning sensation in the
16

stomach after eating, sudden weight loss, and also vomiting are some symptoms of
peptic ulcer.
 Treatment/prevention - taking antibiotics and practicing healthy lifestyle can
be a treatment of this disease. Doing some exercise can help too.
Colon cancer – it is caused by the uncontrolled growth of abnormal cells in the large
intestine. It is very common to adults. The signs and symptoms of this disease are
the following: fatigue, unexplained weight loss, blood in your stool, constipation,
abdominal discomfort such as cramps, and vomiting. It is the third common cancer in
the Philippines based from the data of the Philippine Cancer Society.
 Treatment/prevention - Colon cancers are treated by undergoing a process of
surgeries including radiotherapy and chemotherapy. In order to prevent the
occurrence of this disease, practicing a healthy lifestyle, well-balance food
intake, and doing some exercise is highly recommended.
There are also common digestive disorders that may happen in our digestive system
which can be considered as disturbance in the normal flow of digestion. Below is the list of
common digestive disorder.




Diarrhea – it is usually called ‘stomach flu’. A person with diarrhea may experience
bloating, abdominal cramps, nausea, vomiting, loose and watery bowel. This disorder
is caused by infection of bacteria that came from the food we eat or allergies from
certain food.
 Treatment/prevention – rehydration or drinking plenty of water/energy drinks
that is rich in rehydration salts) is highly recommended to avoid dehydration.
Consulting a doctor is a must too for better and prescribe medication
Constipation – this disorder is characterized by infrequent bowel movement. This
results from a blockage in the large intestine or sometimes it is due to lack of fiber or
water in our body.
 Treatment/prevention – eating foods that are rich in fiber such as the
bananas, apples, and avocados. Drinking plenty of water and having regular
exercise may help regulate bowel movement.
Lactose intolerance – this is the inability of the body to digest lactose (sugar). It is
caused of the lack of the enzyme lactase which is needed to digest lactose. Drinking
milk, eating yogurt, or taking any dairy products may lead to bloating, abdominal
cramps, or diarrhea.
 Treatment/prevention - people who experience lactose intolerance may take
lactase supplements before eating food that contains lactose.
Obesity – it is the abnormal accumulation of fat in the body. It occurs when the body
consumes more calories than it burns. Too much consumption of food causes the
body to store fat and lack of physical activities such as exercise prevents the fat from
being metabolized by the body. People who are obese have a high risk of having a
high cholesterol level, diabetes. High blood pressure, heart diseases, and cancer.
 Treatment/prevention - eating a balanced diet, regular exercise, healthy
weight loss, and practicing a healthy lifestyle may prevent a person for being
obese.
17

What’s More
Activity 3. Complete Me
Directions: Fill in the table with correct answer.
Digestive
Diseases/Disorders
Causes
Possible Treatment
1.
Uncontrolled growth of
abnormal hormones in
the large intestine
2.
Lactose intolerance
3.
Tae lactase supplements
before eating any dairy
products
Constipation
4.
5.
6.
Cause by infection of
bacteria that came from
food we eat. Usually
called “stomach flu”
7.
Obesity
8.
9.
Peptic Ulcer
10.
Take antibiotics and
adapt healthy lifestyle.
18
What I Have Learned
Activity 4. Tell Me
Directions: Cite some possible disease/disorder and its treatment for every situation given.
Explain briefly. Write your answers in your notebook.
1. Jennie had been complaining about her abnormal bowel movement. She only poop three
times a week.
Solution:
______________________________________________________________________
______________________________________________________________________
2. Cathy always feel a burning sensation every after she eat and she tend to vomit
everything she ate. She then observes that she unexplainably loss weight.
Solution:
______________________________________________________________________
______________________________________________________________________
3. Lean experienced a severe chest pain and difficulty in swallowing.
Solution:
______________________________________________________________________
______________________________________________________________________
4. Leonor loves to eat. Her weight is not ideal for her age and height.
Solution:
______________________________________________________________________
______________________________________________________________________
What I Can Do
Activity 5. Question and Answer
Direction: Do a survey to the members of your family about digestive diseases they have
experienced and how treated it. Consolidate their answers in your notebook.
19
Summary
In this module we have learned that:
1. The digestive system consists of different phases/processes such as the ingestion,
absorption, assimilation, and excretion.
2. Ingestion is the first process of digestion and it refers to the entry of food into the
alimentary canal through the mouth.
3. Mouth, tongue, teeth, and saliva work together to perform the ingestion process.
4. The food we eat undergoes mechanical and chemical digestion: (1) mechanical
digestion is the physical tearing, grinding, and chewing of food. (2) Chemical digestion
is the type of digestion that happens in mouth and the stomach. In the mouth, the
presence of the enzyme amylase in our saliva helps in digesting the food we eat. The
presence of different enzymes in our stomach also helps in the chemical digestion of
the food.
5. The second phase of digestion is the process of absorption. It is the process in which
the nutrients from the digested food are being absorbed and distributed into the
bloodstream. Most of the absorption process happens in the small intestine. The lining
of the small intestine has finger-liker projections called villi and microvilli which
increases the surface area for absorption.
6. The nutrients are absorbed by processes of passive diffusion, facilitated diffusion, and
active transport.
7. 90% of ingested water, vitamins, minerals, carbohydrates, proteins, and lipids are
absorb by the small intestine.
8. Assimilation is the third phase of digestion. It is the process of taking in digested food
nutrients into the cell by providing materials in building new protoplasm and energy
needed during the cell activities.
9. Digested food products should be assimilated into the cell because of the following
reasons; (1) they provide energy needed in cell activities. (2) They are converted into
protoplasm. (3) They are converted to build cell membranes for example the fats are
needed for the formation of the cell membranes.
10. Excretion is the last phase of digestion process. It is the process responsible for
removing waste and excess waste from the body. It works with the excretory system.
One organ that involve in the excretory system is the liver. The liver breaks down
harmful substances in the blood and the by-products go into the large intestine where
they eventually excreted in the form of feces.
11. Gastroesophageal reflux Disease (GERD), colon cancer, gastritis, peptic ulcer,
diarrhea, constipation, obesity, and lactose intolerance are just few of the many
diseases and disorders of the digestive system.
12. Practicing a healthy lifestyle is the best way to prevent the occurrence of any digestive
diseases in our body.
20
Assessment (Post-Test)
Direction: Read carefully and answer the questions below. Choose the letter of the
correct answer and write your answer on your notebook.
1.
What is the best treatment for a person who suffers lactose intolerance?
A.
B.
C.
D.
2.
What happen during the assimilation process?
A.
B.
C.
D.
3.
It helps in the digestion of proteins.
It helps in the digestion of fats.
It helps in the digestion of carbohydrates.
It helps in the digestion of lipids.
It is characterized as loose bowel caused by an infection of bacteria that we
get from the food we eat.
A.
B.
5.
Absorbed nutrients are delivered into the cell
Breaking down of food into tiny pieces
Elimination of waste product of the digestion process
Absorption of nutrients from the digested food
How does the enzyme amylase help in the absorption of nutrients?
A.
B.
C.
D.
4.
Take antibiotics
Balanced diet
Take lactase supplements before eating food contains dairy
Practice healthy lifestyle
Diarrhea
Peptic Ulcer
C.
D.
Gastritis
GERD
How saliva helps in the digestion process?
A. It reabsorbs nutrients from the food we eat.
B. It contains the enzyme amylase that helps in the digestion of starch.
C. It absorbs nutrients and distribute it in the bloodstream.
D. All of the above
6.
How colon cancers can be treated?
A.
B.
C.
D.
7.
By eating foods rich in fiber
By exercising
By taking lactase supplements
By undergoing surgeries
Where does reabsorption of nutrients and minerals take place?
A.
B.
Small intestines
Stomach
C.
D.
21
Esophagus
Large intestine
8.
9.
10.
What is the best treatment for people suffering obesity?
A. Undergoing surgery
B. Healthy lifestyle and balance diet
C. Taking pills
D. All of the above
Where does digestion begin?
A. Mouth
C.
B. Stomach
D.
The following are causes of gastritis EXCEPT:
A. Excessive consumption of coffee
B. Too much eating
C. Cigarette smoking
D. Too much intake of inflammatory drugs
22
Small intestine
Large intestine
Pre-Test
1. D
2. B
3. B
4. D
5. A
6. A
7. A
8. D
9. B
10. B
23
Post-Test
1. C
2. A
3. C
4. A
5. B
6. D
7. D
8. B
9. A
10. B
LESSON 1
Activity 1:
Large intestine
Stomach
Mouth
Esophagus
Teeth
Activity 2
1. The Ziplock represent as the mouth. The water as the saliva and the scissors as the teeth.
2. The teeth help in mechanical digestion of food by tearing, grinding, and chewing the food we eat.
3. The saliva helps to moisten food and it contains the digestive enzyme amylase which helps the
digestion of starch.
4. The ingestion process starts when we take in food in our mouth. The teeth then help in breaking
down the food by chewing, tearing and grinding. The saliva helps to moisten food and aid in
breaking down the food into tiny pieces. After the initial digestion, the tongue helps in pushing
the bolus by swallowing the food to throat and into the opening of the esophagus.
Key to Answers
24
LESSON
Activity15: Define Me
Activity
3 crossing over.
1.
Define
Answer: It is the exchange of genetic material during sexual reproduction between
two homologous chromosome's non-sister chromatids that results in recombinant
chromosomes.
What phase does it occur?
Answer: during prophase I of meiosis before tetrads are aligned along the equator
in metaphase I. By meiosis II, only sister chromatids remain and homologous
chromosomes have been moved to separate cells.
2. Diploid
4. Diploid
3. Diploid
5. Haploid
Activity 6: Answer Me
1. What is the role of mitosis and meiosis in cell-division cycle?
Answer:
During mitosis, a cell duplicates all of its contents, including its chromosomes, and
splits to form two identical daughter cells. Meiosis also allows genetic variation
through a process of DNA shuffling while the cells are dividing. Mitosis and
meiosis, the two types of cell division.
2. Explain their role briefly in cell-division cycle
Answer:
Mitosis is a process where a single cell divides into two identical daughter cells (cell
division). During mitosis one cell? divides once to form two identical cells. The
to replace worn out cells.
major
Activity
4 purpose of mitosis is for growth and
Make use of this rubrics in checking students’ output
Activity
5
Meiosis
in Humans, however, the primary function of meiosis is the reduction of the
Answers
may
vary.
ploidy
(number
of chromosomes) of the gametes from diploid (2n, or two sets of 23
chromosomes) to haploid (1n or one set of 23 chromosomes).
25
LESSON 2
Activity 1
1. Ingestion
2. Teeth
3. Tongue
4. Digestion
Activity 2
1. The stocking represents the small
intestine.
2. The nutrients from the digested
food are being absorbed with the
use of villi and microvilli.
3. Because of the presence of the
villi and microvilli, the nutrients are
absorbed by the inner walls of the
small intestine into the
bloodstream.
Activity 3
Activity 4 & 5
Make use of the scoring rubrics.
LESSON 3
Activity 1
1. Absorption
2. Small intestine
3. Villi
4. Microvilli
26
LESSON 3
Activity 2
Activity 3
1. Carbohydrates
- Carbohydrates breakdown into glucose and reach out the liver by hepatic portal veins. Inside
the liver, the excess of glucose is converted into glycogen.
2. Fats
-The fats are stored in liver, bone, and adipose tissue like our thighs. Some fats also enter into the
composition of cell organelles.
3. Amino acids
It reaches the hepatic portal veins and some amino acids are converted into urea with the
carbon dioxide.
LESSON 4
Activity 1
1. Assimilation
3. Bloodstream
4. Storing nutrients
Activity 2
1. The stocking serves as the large intestine.
2. After the absorption ad assimilation process in
the small intestine, the undigested food moves
to the large intestine. The large intestine will reabsorb the water and minerals that are not
digested in the small intestine. The rest of the
undigested materials move to the rectum until
they are eliminated from the body.
Activity 3
1.
Large Intestine – The large intestine reabsorbs the water and minerals from the undigested materials
from the small intestine. After that, the undigested materials move to the rectum until they are
eliminated from the body through the anus.
Activity 4 – Answers may vary. Use the rubrics provided.
Activity 5
Excretion is important to maintain the homeostasis of our body. All the waste materials in our body need to
be eliminated since it can intoxicate our body and may lead to serious problem.
27
LESSON 5
Activity 1
1. Small intestine
2. Assimilation
3. Mouth
4. Saliva
5. Colon
Activity 2 – Answers may vary.
Activity 3
1.
Colon cancer
2.
Undergo surgery
3.
Inability of the body to digest sugar/lactose
4.
Lack of water and fiber of the body
5.
Eat food that are rich in fiber/drink plenty of water
6.
Diarrhea
7.
Drink plenty of water/ consult a doctor for better treatment
8.
Too much consumption of food and lack of physical activities
9.
Healthy lifestyle/ balance diet/ weight loss/ doing some exercise
10. It is caused by the bacteria H.pylori and also too much intake of acidic drinks such as alcohol
Activity 4
(Possible Answers)
1.
Jennie probably experiencing constipation. Drinking plenty of water and eating foods such as
bananas and apples which are rich in fiber may help to have a regular bowel movement.
2.
Cathy perhaps have peptic ulcer. Taking prescribed antibiotics may help her and practicing a
healthy lifestyle will be a good treatment for her.
3.
Lean probably had GERD. Making restrictions in her intake such as no to spicy foods,
chocolates, alcoholic drinks, coffee, and fatty foods may help her not to experience GERD again.
Taking prescribed medicines is big help too.
4.
Leonor most probably is obese. Practicing a healthy lifestyle and being conscious to her intake
will be a big help for her to lose weight. Doing some exercise such as jogging will be a big help
too.
Activity 5 – Answers may vary.
References
Biggs et.al (2012). Biology. Quezon City:McGraw-Hill Education (Asia) and Phoenix
Publishing House, Inc..
Pabellon et.al (2018). Exploring Our World: An Interactive Approach. Quezon City:Dane
Publishing House,Inc..
Ian Mark Allas et, al. Discovery Science 8 K to 12 Edition Textbook. Makati City.Diwa
Learning Systems, Inc. 2013.
https://study.com/academy/lesson/assimilation-of-food-in-the-digestive-system.html
https://www.youtube.com/watch?v=t7vtWYBfbyU&vl=en
https://www.youtube.com/watch?v=t7vtWYBfbyU
https://link.springer.com/chapter/10.1007%2F978-1-4612-5126-2_5
https://www.khanacademy.org/science/high-school-biology/hs-human-body-systems/hs-thedigestive-and-excretory-systems/a/hs-the-digestive-and-excretory-systems-review
https://www.mayoclinic.org/diseases-conditions/colon-cancer/symptoms-causes/syc20353669
https://www.webmd.com/digestive-disorders/digestive-diseases-lactose-intolerance#1
28
For inquiries and feedback, please write or call:
Department of Education – Bureau of Learning Resources (DepEd-BLR)
Department of Education – Division of Gingoog City
Office Address:
Brgy. 23, National Highway,Gingoog City
Telefax:
088 328 0108/ 088 328 0118
E-mail Address:
gingoog.city@deped.gov.ph