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parts of the digestive system

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					           Are You Ready For This Module?

    Let’s us find out.

PICK OUT THE BEST ANSWERS. WRITE ONLY THE LETTER:
    1. All the parts of the body are made up of:
       a. bones
       b. muscles
       c. cells
       d. water
    2. Your face is wet. You wipe it with a towel. Your face becomes dry because
       moisture or water is ___________ by the towel.
       a. absorbed
       b. added
       c. made dirty
       d. made clean
    3. A person who constipates often has
       a. difficulty in eating
       b. difficulty in breathing.
       c. delayed and hard passage of dry body waste through the rectum
       d. easy passage of body waste through the rectum
    4. Food that gives bulk to our diet are those that
       a. are soft such as milk and porridge
       b. are fatty and oily
       c. contain fibers which cannot be digested, such as camote, papaya and
            pechay.
       d. are cooked


RAISE YOUR HAND TO SHOW THAT YOU ARE READY FOR THE GROUP
DISCUSSION.

IF ALL YOUR ANSWERS ARE CORRECT GO TO PAGE 4 AND READ LESSON
1.

IF YOU HAVE ONE OR MORE MISTAKES, READ GETTING READY O THE
NEXT PAGE.


                                       1
            Getting Ready


READ AND UNDERSTAND THESE.

     1.   CELLS are tiny particles used in body building. When put together, cells
          make up our bones, skin, muscles, hair, intestines and all our body parts.

     2.   ABSORB means to take up moisture; to receive or swallow up, as: The dry
          cloth absorbs the water very fast.



              Do These


     Put a few drops of water on the table. Put dry cloth or rag over it. Remove the
cloth. The table is now dry. The cloth is moist. The cloth has taken up the moisture. It
has absorbed the water.

     3.   A person who constipates has difficulty in moving his bowels. When a
          person has constipation, bowel movement is delayed and there is difficulty
          because the dry body waste cannot pass out of the anus easily.

     4.   Bulky food are those that give bulk or volume to the food in the intestine.
          Some bulky food are fruits and vegetables. These are bulky food because
          they contain fibers that cannot be digested. These undigested fibers are sent
          to the intestine together with water and other digested food. This bulk will
          make the intestine work so that the food is moved along the intestine.




                                           2
 LESSON



  1          How Food Is Digested

    Do you enjoy telling your friends about some of your interesting experiences?

    Let’s read this story about what happened to Rita one day




                                      Never Again

        I’ll never eat green mangoes again. Do you want to know why?

        On my way home from church yesterday, I dropped by Tia Marina’s fruit
   store. My aunt gave me a bag full of big green mangoes to take home. My mouth
   watered when I saw the mangoes so I tasted one. I liked it and I ate some more. I
   was hungry that I ate some more. I was so hungry that I ate three more. That night,
   my stomach ached so much and I cried. I thought I would die, but I couldn’t tell
   my mother. How could I?

                                              Adapted from Everyday
                                              English for Grade 4.


    Read the title and beginning sentences of Rita’s story again. Do they make you
want to know why Rita won’t ever eat green mangoes again?




                                          3
                                     NEVER AGAIN

           I’ll never eat green mangoes again. Do you want to know why?


    Rita’s story is good because it has an interesting title and good beginning. It also
answers the following questions.

          Questions                                  Answers

     1.   When did the story happen?                 Yesterday


     2.   To whom did it happen?                     Rita

     3.   Where did it happen?                       In Tia Marina’s fruit store

     4.   What interesting thing happened?           Her Aunt gave her a bag full of
                                                     green mangoes.

     The set of pictures below tells a story.

     Let’s write a story about them. The leader will ask the members of the group to
take turns in giving the title, the beginning sentence, and one sentence each until the
story is completed. You will first write your group story on the blackboard.

    A.    1.




                                           4
      2.




      3.




      4.




AFTER THE GROUP DISCUSSION, COPY THE STORY ON YOUR ANSWER
SHEET.

                            5
    Here are some things we should remember so that we can tell a good story.

    1.   The title should be interesting.

    2.   The beginning sentence of a story should be interesting. It should
         make a listener or reader want to know more.

    3.   A good story should tell the who, whom, where, and what of the story.

     Below is another set of pictures. Look at each picture carefully. Then write the
story that the picture suggests.




AFTER WRITING YOUR ANSWERS, RAISE YOUR HAND TO SHOW THAT
YOU ARE READY FOR THE GROUP DISCUSSION.




                                            6
 LESSON



   2         Our Digestive System

     In lesson 1, you have read the story of Rita. It tells what happened to her after
eating green mangoes. She had a stomachache. Do you know why this happened? Rita
had indigestion. This means that something went wrong in Rita’s digestive system.

    Our digestive system plays an important role in the process of digestion. So, it is
important that we understand our digestive system.

     In this lesson, you will study our digestive system.

     Our body is made of tiny cells. Cells are very small particles that are used to build
our bodies. They are so tiny that they cannot be seen without a microscope.




    All the cells in the body need food in order to live and grow. But the cells cannot
absorb or swallow up a bite of banana, a piece of bread or a piece of meat. Our body
cannot take even the smallest particle of meat directly into the bloodstream.




                                            7
                    Glow                                      Go




                                         Grow


     Food has to be broken down into the smallest units that cells can absorb. This
process of breaking down food so that it can be taken to the bloodstream and absorbed
by the cells is called digestion. Digestion is done by the digestive system.

    The process of digestion must changed solid food into another form which can
be absorbed by our body cells.

     Several things happen to food from the time we eat it until it is ready to be
absorbed by the blood. It must be broken down into very, very small pieces and
softened. It must be mixed with the different juices. These digestive juices in the body
help change the food into its simple liquid form. Then this is ready to be absorbed by
the blood and cells.

     The digestive system, or food factory of the body, is made up of the mouth,
esophagus, or food tube, stomach, small intestine and large intestines. It is sometimes
called the food canal. It is also called the alimentary canal. Study the picture carefully.


            mouth

                                                       esophagus


                                                       stomach


                                                       small intestines

                                                       large intestines

                                            8
     Food is broken up as it passes from the one part of the canal to another. When it
reaches the small intestines, digestion is completed. Then food is absorbed by the
blood to be distributed to all parts of the body.

    Let us study how the digestion of food takes place.

    1.   Digestion of food begins in the mouth. Here the food is chewed by the teeth
         and broken into small pieces. This is mixed with saliva in the mouth. The
         saliva helps make the food for digestion in the stomach.




    2.   From the mouth, food passes through a tube called the esophagus. Then it
         enters the stomach.

             In the stomach special juices called digestive juices act on the food.
         Different digestive juices act on different kinds of food and digest it into a
         soft mass. The walls of the stomach also help by squeezing it until it becomes
         thick liquid.



                                                     esophagus




                                                     stomach




                                          9
     Here is how a stomach looks when it is digesting food.




     A.   Stomach when full at lunch time (12:00 Noon)




     B.   After two hours of squeezing and turning, the stomach is only half-full.




     C.   After four hours the stomach is almost empty. Food goes into the small
          intestine.

3.   From the stomach food is moved down to the small intestines. The most
     important part of digestion takes place in the small intestines. Other digestive
     juices act on the food.

                                      10
    Most of the food is absorbed by the walls of small intestine and taken by the
blood to all parts of the body.

     Food that can not be digested is sent to the large intestines. Food that is not
absorbed in the large intestines is passed out of the body as body waste. Body waste
is passed through the rectum by bowel movements.

A. ANSWER THE QUESTIONS CORRECTLY. WRITE YOUR ANSWERS IN
   YOUR ANSWER SHEET.

         1.   What happens to the food in the mouth?
         2.   How does the stomach help in the digestion of food?
         3.   Where does digestion of food begin?
         4.   Why do cells need food?
         5.   How does the small intestine help in the digestion of food?

AFTER WRITING YOUR ANSWERS, RAISE YOUR HAND TO SHOW THAT
YOU ARE READY FOR THE GROUP DISCUSSION.


    Here is where and how the digestion of food takes place:

    1.   The mouth                –      Food is chewed and mixed with saliva.
                                         Saliva moisten the food and helps digest it.

    2.   The esophagus            –      This is the tube where food passes on its
                                         way to the stomach.

    3.   The stomach              –      This is a curved sack-like enlargement that
                                         contracts to squeeze food and mixes it with
                                         the digestive juices.

    4.   The small intestines     –      Here, the food is finally digested and
                                         absorbed by walls of the intestines and
                                         carried by the blood.

    5.   The large intestine      –      This is where the undigested food goes.
                                         This waste material is eliminated out of the
                                         body through bowel movement.

                                         11
            Self-Test (Lesson 2)

A. TRACE THE PASSAGE OF FOOD FROM TIME FOOD ENTERS THE
   BODY TO THE LARGE INTESTINE.

     1.
     2.
     3.
     4.
     5.

AFTER WRITING YOUR ANSWERS RAISE YOUR HAND TO SHOW THAT
YOU ARE READY FOR THE GROUP DISCUSSION.


B.   MATCH COLUMN A WITH COLUMN B. WRITE ONLY THE LETTER.

            A                                     B

     1.   Mouth                a.    helps the teeth swallow the food.

     2.   Tongue               b.    the place where digestion begins.

     3.   Stomach              c.    a hollow muscular bag at the end
                                     of the esophagus.

     4.   Small intestine      d.    squeezes most of the undigested
                                     food.

     5.   Large intestine      e.    the place where the food almost
                                     becomes a liquid.

AFTER WRITING YOUR ANSWERS, RAISE YOUR HAND TO SHOW THAT
YOU ARE READY FOR THE GROUP DISCUSSION.




                                    12
 LESSON
             Structures And Functions Of The
  3          Parts Of The Digestive System

    Where does digestion start? What helps in the digestion of food? How does it
happen?



              Do These

    Prepare the following:

    guavas         pieces of bread or boiled bananas

     Take a bite on one of the guavas. What part of the teeth do you use? Chew the
small piece. Take note of the teeth you used.

    Do the same with the banana or bread. Observe and compare your findings.

AFTER THE ACTIVITY, DISCUSS YOUR OBSERVATIONS WITH YOUR
GROUP.


THE MOUTH AND THE TEETH

    Digestion begins in the mouth. The teeth cut and chew the food into small pieces.
They break down, chop and grind the food so that it can be swallowed easily.

    There are different kinds of teeth. Different teeth perform different function in
breaking down the food you eat.




                                         13
     The different kinds of teeth are:

     1.   Central Incisors
     2.   Lateral Incisors
     3.   Canines
     4.   First Bicuspids
     5.   Second Bicuspids
     6.   First Molar
     7.   Second Molars
     8.   Third Molars

     Permanent Teeth

     1.   Central Incisors                         1
     2.   Lateral Incisors                       upper
     3.   Canines
     4.   First Bicuspids
     5.   Second Bicuspids
                                                 lower
     6.   First Molar
                                                   1
     7.   Second Molars
     8.   Third Molars


     The teeth are named after their shape or the function they perform.

     The incisors which are shaped like chisels cut the food.

     The canine teeth which look like the dog’s teeth tear and shred the food.

     The bicuspids or premolars also tear and crush the food.

     The molars crush and grind food.

     In the mouth, the food is moistened or wet by the saliva to make its passage
down to the esophagus easier. Saliva is a digestive juice which is secreted by the
salivary glands. It contains an enzyme called ptyalin which acts on starches and changes
them into sugar. Everyday the salivary glands produce 1 ½ liters of saliva.




                                          14
            Answer These


     1.   What is the shape of the incisors and what function do they perform?
     2.   How do canine teeth look like and what are their function?
     3.   What is the function of the bicuspids?
     4.   What happens to the food in the mouth?
     5.   What kind of digestive juice is secreted by the salivary glands?

AFTER WRITING YOUR ANSWERS, RAISE YOUR HAND TO SHOW THAT
YOU ARE READY FOR THE GROUP DISCUSSION.


THE TONGUE

     You learned that the teeth chew and cut the food into small piece. You also
learned that they break down, chop and grind the food so that it can be swallowed
easily.

     What do you do after chewing the food?

FIND OUT BY DOING THIS ACTIVITY:

                                 ACTIVITY

   Get a piece of biscuit. Take a bite and swallow it. Can you swallow it as it is?
Why?

     Can you swallow your food without your tongue? Why?

AFTER WRITING YOUR ANSWERS, RAISE YOUR HAND TO SHOW THAT
YOU ARE READY FOR THE GROUP DISCUSSION.

    Your tongue helps the teeth swallow the food you eat. It is a strong muscle that
mixes the saliva and the food. Then, it turns the food inside the mouth so the teeth can
break it up. When the food is already finely cut up, the tongue then pushes it to the
back of the mouth and into the throat.

                                           15
         epiglottis




          vallate papillae

                                                             filiformpapillae


          funjiform papillae




             The tongue is a strong muscle that mixes the saliva and the
         food in the mouth.


THE PHARYNX AND THE ESOPHAGUS

    Look at the illustration below. It shows the pharynx and the esophagus.




                                                            pharynx




                                                              esophagus

          windpipe




      When you swallow the food you eat, it slips down the throat and passes through
the pharynx. There are two passages leading out from the pharynx; one is the esophagus
which is the passage for the food and the other is the windpipe which is the passage
for the air. The muscles of the pharynx move the food to the esophagus. This is a tube
leading from the throat to the stomach. It is about 25 cm long.

                                         16
              Do These

                                ACTIVITY

    Prepare a glass of cold water or juice.

    Drink the cold water or juice. While drinking, put your other hand on the front of
your neck.

     Can you feel the movement as you swallow the cold water or juice? Can you feel
the water going down?




AFTER WRITING YOUR OBSERVATIONS, RAISE YOUR HAND TO SHOW
THAT YOU ARE READY FOR THE GROUP DISCUSSION.


    When you swallow something, the opening of your windpipe closes. If you talk
while swallowing, the food may get into the windpipe.

   The muscles of the esophagus move the food toward the stomach. The squeezing
movement of the muscles of the esophagus is called peristalsis.

    What is peristalsis?




                                          17
              Do This

                                       ACTIVITY

    Get a tube of slightly used toothpaste. Then squeeze both ends. What happens?

     Remove the cover of the toothpaste. What happens? Then, still without the cover,
repeat the first step.

AFTER WRITING YOUR OBSERVATIONS, RAISE YOUR HAND TO SHOW
THAT YOU ARE READY FOR THE GROUP DISCUSSION.

     The movement of the food inside your esophagus is similar to the movement of
the toothpaste from its tube. The food is forced into the stomach by peristalsis.

    The pharynx or throat is a muscular tube used for swallowing and breathing.

    There are two passages leading from the pharynx: one is the esophagus for
    the food and other is the windpipe for the air.

    The squeezing movement of the muscles of the esophagus is called peristalsis.


THE STOMACH

     Feel your stomach and describe its
location.

     What goes into your stomach? What
happens to your stomach after you have eaten
a heavy meal? Why? How do you feel when
you are hungry?


AFTER WRITING YOUR ANSWERS, RAISE YOUR HAND TO SHOW THAT
YOU ARE READY FOR THE GROUP DISCUSSION.



                                         18
    Your stomach is a hollow muscular bag at the end of the esophagus. It is just
above your waistline on the left side. Below your waistline is your abdomen, not your
stomach.

      Before eating, your stomach can look like a sausage. After eating plenty of food,
it can look like a football.

                                                         lumen of gland




                          mucous coat
                          submucous coat
                          muscular coat
                          serous coat


     The inside walls of the stomach are covered with glands that make gastric juice.
This walls tumble, shake, squeeze and mix the food with the gastric juice. So the food
look like a thick soup. Everyday, about two liters of gastric juice is made in the stomach.



               Do These

                                  ACTIVITY

     Prepare the following materials:

     2 lumps of sugar
     2 bottles of water with cover

     Put one lump of sugar each in two separate bottles of water. Cover the bottles.

    Let one bottle stand still. Shake the other bottle steadily. In which bottle does
sugar dissolve easily? Why?

AFTER WRITING YOUR OBSERVATIONS, RAISE YOUR HAND TO SHOW
THAT YOU ARE READY FOR THE GROUP DISCUSSION.

                                            19
THE SMALL AND LARGE INTESTINES

     Look at the drawing below. It shows the large intestine and the small intestine.



                                                           small intestines


                                                           large intestines




     The small intestine is long. It is about 6.5 meters and is highly coiled. It would be
four or five times the length of your body if you were to lay it straight on the floor. It is
connected to your stomach. It is also lined with muscles that have peristalsis movement.

     The intestine has it parts. Duodenum is the first part. From its walls the liquid
substances flow. The bile flows into the intestines from the liver and juice from the
pancreas. Bile helps digest fatty foods. Pancreatic juice helps digest starches and
proteins. It also digests fats.

    In the intestine, the food also becomes liquid. Food nutrients are absorbed by the
body through the blood vessels along the intestinal walls.

     The walls of the small intestines are lined with villi. Villi look like tiny fingers. They
separate the food nutrients ready to be absorbed by the walls from the food that is not
ready yet. The food nutrients flow into the bloodstream which distributes them to the
cells of the body through the villi. When the oxygen in the cells join with the food
substance, energy is released. Here you get energy for work and play.

     The undigested food goes to the large intestine or colon as waste. The large
intestine is bigger and shorter than the small intestine. It is about one meter long. It
almost surrounds the small intestine.

      The large intestine squeezes most of the water of the undigested food. The water
passes through the walls of the large intestine. It is carried by the blood to the different
tissues of the body. The undigested food becomes solid called feces. It contains
germs and gases. The large intestine stores feces for 12 hours or more. Then, peristalsis
pushes it out of the body through the rectum. This is the lowest end of the large
intestine.

                                              20
          Self - Test (Lesson 3)

A. COPY THE STATEMENT OR SENTENCE THAT ANSWERS EACH
   QUESTION. SELECT YOUR ANSWERS BELOW EACH QUESTION.

   1.   What does the mouth do with the food you eat?

        – It chews and mixes the food with the saliva.
        – It only mixes the food you eat.
        – It pushes the food to the esophagus.

   2.   What is the function of the esophagus?

        – It is the storage of food inside your body
        – It mixes the food inside your body
        – It is a tube where the food passes on its way to the stomach.

   3.   What happens to the food in the stomach?

        – It is squeezed and mixed with the digestive juices.
        – All the food nutrients are mixed with the digestive juices.
        – Food is pushed down to the rectum.

   4.   Which of the following describes the changes of food in the small intestines?

        – Here, the food is absorbed by the walls of the intestines and carried by
          the blood.
        – Here the food is digested and changed into sugar.
        – The food is broken into small pieces.

   5.   What happens to the undigested food that you eat?

        – It becomes a soft solid called feces.
        – It stays in your stomach.
        – It stays in your esophagus.

AFTER WRITING YOUR ANSWERS, RAISE YOUR HAND TO SHOW THAT
YOU ARE READY FOR THE GROUP DISCUSSION.
                                        21
 LESSON
              Good Health Habits For Your
  4           Digestive System

     There are times when you have indigestion. This means that your food was not
easily digested. Indigestion may make you vomit or may cause diarrhea. This happens
when your body waste becomes soft and watery and you move your bowels many
times a day.

    So, we must take good care of our digestive system.

     Here are some practices that will help you take good care of your digestive
system so that it can work well.

    1.   You must eat a well-balanced diet.

         There are three groups of food nutrients. They are:

         a.   The body building group which includes fish, meat, chicken, eggs, nuts
              and beans.




         b.   The energy-giving group. Rice, corn and other cereals, tubers, fats and
              oil are examples of this group.




                                         22
     c.   The body-regulating group. This group includes fruits and vegetables.




     It is necessary to eat food from each group everyday. If you do so, you can be
sure that your body is getting all the nutrients it needs.



              Do These

                                 ACTIVITY

     List the food you have eaten for everyday meal including snacks between meal.

AFTER DOING THIS ACTIVITY, DISCUSS YOUR LIST WITH THE GROUP.


     2.   You should eat regularly.




     Eating your meals at regular time, with snacks in between, will help your digestive
system work more smoothly. It will also make you feel better.




                                           23
              Do These


                                 ACTIVITY

    Prepare a record of the time you eat breakfast, lunch, supper, and snacks for one
week.

    Observe how regularly you eat your meals. Then, try to recall how you feel when
you miss a meal.

AFTER THE ACTIVITY, DISCUSS YOUR OBSERVATION WITH THE GROUP.


     3.   Eat your breakfast. The most important meal of the day is breakfast. Your
          breakfast should be full so that it will keep you going the whole day. It will
          make you feel better in school. It will also make you work better.

     Your breakfast should at least take one-fourth of your day’s requirement of protein
of your body-building foods.




              Do These

                                 ACTIVITY

     Prepare a breakfast menu. Include first protein foods before adding other foods.

AFTER THE ACTIVITY DISCUSS YOUR MENU WITH THE GROUP.


                                          24
    4.   Eat pleasantly. Your feelings affect digestion. When you are happy and
         cheerful at mealtime, you can help your digestive system work well. When
         you are afraid, worried or angry the digestive juices stop flowing. Then
         digestion maybe delayed.

         There may be times when digestion happens faster because of upset emotion.
         This kind of emotion may make the stomach secrete too much acid. If this
         happens, part of the lining of the stomach or small intestine may be affected.
         Wound or ulcer may develop if this happens.

    Be cheerful at meantime so that your digestive system can work well.




    5.   Eat food that is easily digested, such as fruits, vegetables, fish and softly-
         cooked meat.

     Some fruits and vegetables are eaten raw or uncooked, such as tomatoes, carrots,
sincamas and ripe fruits. Ripe fruits such as green mangoes, guavas, bananas are not
easily digested.

    Meat should be cooked until soft. Tough or hard meat takes a long time to digest.

     Fatty or oily food should be eaten in small amounts. Too much fatty or fried food
delays digestion.




                                          25
     6.   Chew food well.

     Chewing food well is another way of helping the digestive system. The stomach
digests food easily if the food is chewed thoroughly. Large pieces of food take a
longer time to digest.

     Do not be in a hurry when eating. Chew the food well.




     7.   Rest before and after eating.

     You must not work or play too hard just before or after you eat. Food will not be
digested if you are tired. You need to rest just before and after eating. This will give
your digestive system a chance to do its work well.

     8.   Do not overeat.

    Overeating overworks your stomach. Too much food at one time makes the
stomach do more work. Too much food takes a very long time to digest. Some of the
food takes a very long time to digest. Some of the food are not even digested at all
when you eat too much.

     Give your stomach time to rest. The stomach rests when it is empty.




                                          26
           Self -Test (Lesson 4)

A. ANSWER THESE QUESTIONS CORRECTLY. WRITE YOUR ANSWERS
   ON YOUR ANSWER SHEET.

    1.   What causes indigestion?
    2.   What should you do after eating?
    3.   What kind of food should you eat so that you will not have indigestion?
    4.   When is the best time to eat?
    5.   How do you know that you have indigestion?
    6.   How can you take care of your digestive system so that it can work well?

AFTER WRITING YOUR ANSWERS, RAISE YOUR HAND TO SHOW THAT
YOU ARE READY FOR THE GROUP DISCUSSION.



           Remember


    Here are the things you must remember in order to help your digestive system
work well.

    1.   You must eat a well-balance diet.
    2.   You should eat regularly.
    3.   Eat your breakfast.
    4.   Eat pleasantly.
    5.   Eat food that is easily digested.
    6.   Chew the food well.
    7.   Rest before and after eating.




                                         27
            Summary


     You have learned many things in this module.

    The digestive system prepares the food for absorption and distribution by the
blood to all parts of the body.

    The organs of the digestive system include the mouth, esophagus, stomach and
small and large intestines.

     The food enters the body through the mouth. There, it is torn and ground by the
teeth, then the tongue mixes the saliva and the food in the mouth. The food passes
through the esophagus in going to the stomach. The stomach is a hollow muscular bag
at the end of esophagus. It contracts to squeeze food and mixes with the digestive
juices. The small intestines finally digest the food.

     Health rules on the proper care of the digestive system must be observed at all
times.

      The food should be thoroughly broken up into small pieces by the teeth before it
is swallowed. This is because food is easily digested by the gastric juices if it is cut
into smaller pieces.

     Pleasant surroundings and cheerfulness at mealtime have a good effect on the
secretion of juices and therefore proper digestion of food is assured.

WHEN YOU ARE READY GO TO THE TESTING CENTER AND TAKE THE
POST-TEST




                                          28

				
DOCUMENT INFO
Description: This is an example of parts of the digestive system. This document is useful for conducting parts of the digestive system.