Download The Digestive System?

Grade 8 Science Related Reading/Life Science
Grade 8 Life Science
8L.6: Digestion
Enzyme Action
Task 1 - Pre- Reading Activity
Look at the picture below and tell in which part of digestive system these
structures are found and what do we call them.( same structure from
different angles)
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Grade 8 Science Related Reading/Life Science
Task 2 – Reading Activity
The Digestive System?
Write the names of
The digestive system is a group of organs that break
digestive organs that
down, or digest, food so your body can get nutrients. The
food passes through.
main organs of the digestive system make one long tube
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through the body. This tube is called the digestive tract.
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The digestive tract includes the mouth, pharynx, esophagus,
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stomach, small intestine, and large intestine.
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The digestive system has several organs that are not
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part of the digestive tract. The liver, gallbladder, pancreas,
and salivary glands add materials to the digestive tract to
help break down food. However, food does not go into
these organs.Liver produce bile that help to digest fats.
How Is Food Broken Down?
The sandwich you eat for lunch has to be broken into tiny pieces to be absorbed into your blood.
First, food is crushed and mashed into smaller pieces. This is called mechanical digestion.
However, the food is still too large to enter your blood. Next, the small pieces of food are
broken into their chemical parts, or molecules. This is called chemical digestion. The molecules
can now be taken in and used by the body’s cells. Most food is made up of three types of
nutrients: carbohydrates, proteins, and fats. The digestive system uses proteins called enzymes
to break your food into molecules. Enzymes act as chemical scissors to cut food into smaller
particles that the body can use.
Digestive enzymes
Digestive enzymes are the chemicals that break large insoluble food molecules into smaller
soluble molecules. Digestive enzymes are classified by the type of food that they affect, so there are five
main types:
Carbohydrase :breaks carbohydrate into smaller sugar
Protease: breaks protein into amino acids.
Lipase : breaks fat into fatty acids and glycerol.
Maltase: breaks maltose into glucose
Amylase: Breaks starch into glucose
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Grade 8 Science Related Reading/Life Science
Add Digestive Enzymes and Hydrochloric Acid to Relieve
Gas and Bloating
(NaturalNews)
Many people experience gas and bloating after eating. Gas can accumulate in the stomach or the
intestines, causing pain, rumbling and indigestion. Gas is a product of incomplete digestion and an
indication that food is fermenting in the gut, instead of being digested properly and absorbed into
the body as nutrients. Digestive enzymes and a change in the digestive pH, by taking betaine
hydrochloric acid, can improve digestion and relieve painful gas and bloating.
As people age, their levels of digestive enzymes decrease, so many find they need to add digestive
supplements to meals. Digestive enzymes come in many forms. Certain foods contain natural
digestive aids, such as pineapple and papaya. Adding a few bites of these foods to every meal can
aid digestion.
Also as the body ages, the amount of hydrochloric acid secreted to aid in digestion decreases. This
leads to a condition known as hypochlorhydria. Hypochlorhydria begins as a gut deficiency and is
one of the leading causes of gas and indigestion, and it can lead to many diseases and chronic
inflammation. Without this important stomach acid, protein cannot be digested and many nutrients
cannot be absorbed. In addition, acid from the stomach is a signal to the pancreas to perform its
function, so hypochlorhydia can lead to problems in the pancreas as well. Diseases associated with
low stomach acid include asthma, lupus, anemia, psoriasis, arthritis, ulcers, and many more.
Indicators of low stomach acid can be simple gas and bloating, or more complex conditions, such as
food allergies, constipation, anemia, and nausea.
To diagnose low stomach acid, add betaine hydrochloric acid to each meal and note any
improvement. For clinical diagnosis, the Heidelberg test can be conducted at a doctor's office
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Grade 8 Science Related Reading/Life Science
Task 3 – Post Reading Activity
Q1: What organs in the digestive system are not part of the digestive tract?
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Q2: How is chemical digestion different from mechanical digestion?
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Q3: What do glands in the stomach produce?
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Q4: Name five important enzymes and their action on particular food.
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Q5: Match the correct description with the correct term. Write the letter in the space provided.
_____ 1. a saclike organ that breaks down food into liquid
a.stomach
______ 2. an oval organ that sends fluid into the small
intestine to chemically digest and neutralize
chyme
b. small intestine
______ 3. a narrow tube covered with nutrient-absorbing
villi
c. pancreas
______ 4. a small, saclike organ that stores bile
d. liver
______ 5. an organ that changes liquid waste into
semisolid waste
e.large intestine
______ 6. a large organ that stores nutrients and breaks
down toxins
f. gallbladder
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Grade 8 Science Related Reading/Life Science
Q6: Choose the best answer:
1. What are the organs that work together to break down food called?
a. the lymphatic system
b. the digestive system
c. the alimentary system
d. the intestinal system
2. Food does NOT pass through which of these organs?
a. stomach
b. pharynx
c. small intestine
d. liver
3. What does bile do to large fat droplets?
a. It turns them into nutrients.
b. It changes them to water.
c. It breaks them into tiny droplets.
d. It changes them to enzymes.
4. What happens to material that can’t be absorbed into the blood?
a. It goes back to the stomach.
b. It is pushed into the large intestine.
c. It is broken down by the liver.
d. It goes to the small intestine.
5. How does chewing help digestion?
a. Chewing makes food taste better.
b. Chewing makes food last longer.
c. Chewing makes food smaller.
d. Chewing makes it harder for bacteria to grow.
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Grade 8 Science Related Reading/Life Science
Q7: Complete the concept map showing the characteristics of enzymes.
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