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The Muscular System
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Printed: September 4, 2015
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C HAPTER
Chapter 1. The Muscular System
1
The Muscular System
Lesson 16.4: True or False
Name___________________ Class______________ Date________
Write true if the statement is true or false if the statement is false.
1.
2.
3.
4.
5.
6.
7.
_______ There are four different types of muscle tissues in the human body.
_______ Aerobic exercise increases muscle endurance.
_______ Tendons attach one bone to another at a joint.
_______ Skeletal muscles work in pairs.
_______ The quadriceps is a muscle in the upper arm.
_______ Sit-ups and pushups increase muscle size and strength.
_______ Muscle contractions are responsible for virtually all movements of the body.
Lesson 16.4: Critical Reading
Name___________________ Class______________ Date________
Read this passage based on the text and answer the questions that follow.
There are three different types of muscle tissues in the human body: cardiac, smooth, and skeletal muscle tissues.
All three types consist mainly of muscle fibers, but the fibers have different arrangements.
Cardiac muscle is found only in the walls of the heart. It is striated, or striped, because its muscle fibers are arranged
in bundles. Contractions of cardiac muscle are involuntary. This means that they are not under conscious control.
When cardiac muscle contracts, the heart beats and pumps blood.
Smooth muscle is found in the walls of other internal organs such as the stomach. It isn’t striated because its muscle
fibers are arranged in sheets rather than bundles. Contractions of smooth muscle are involuntary. When smooth
muscles in the stomach contract, they squeeze food inside the stomach. This helps break the food into smaller
pieces.
Skeletal muscle is attached to the bones of the skeleton. It is striated like cardiac muscle because its muscle fibers
are arranged in bundles. Contractions of skeletal muscle are voluntary. This means that they are under conscious
control. Whether you are doing pushups or pushing a pencil, you are using skeletal muscles. Skeletal muscles are
the most common type of muscles in the body.
Many skeletal muscles are attached to the ends of bones where they meet at joints. The muscles are attached to the
bones by tough bands of connective tissue called tendons. When the muscles contract, they pull on the tendons,
which pull on the bones in turn, causing them to move. Muscles can only contract. They can’t actively lengthen.
Therefore, to move bones back and forth at joints, skeletal muscles must work in pairs. For example, the biceps and
triceps muscles of the upper arm work as a pair. When the biceps muscle contracts, it bends the arm at the elbow.
When the triceps muscle contracts, it straightens the arm.
Questions
1. Compare and contrast cardiac and smooth muscle tissues.
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2. Explain how skeletal muscles function to move bones.
3. Skeletal muscles like the biceps and triceps muscles work in pairs. Explain why.
Lesson 16.4: Multiple Choice
Name___________________ Class______________ Date________
Circle the letter of the correct choice.
1. Each muscle fiber contains many
a.
b.
c.
d.
nuclei.
mitochondria.
myofibrils.
all of the above
2. Cardiac muscle is
a.
b.
c.
d.
striated.
arranged in sheets.
under conscious control.
all of the above
3. Which statement about smooth muscle is true?
a.
b.
c.
d.
It is arranged in bundles.
Its contractions are voluntary.
It is needed for the digestion of food.
It is found in the walls of all internal organs.
4. How many skeletal muscles are there in the human body?
a.
b.
c.
d.
fewer than 60
about 160
about 320
more than 600
5. A single muscle can
a.
b.
c.
d.
only contract.
actively lengthen.
move a bone back and forth.
two of the above
6. The name of the muscle that bends the arm at the elbow is the
a.
b.
c.
d.
biceps muscle.
elbow muscle.
triceps muscle.
upper arm muscle.
7. Which form(s) of exercise would increase the strength of cardiac muscle?
a.
b.
c.
d.
2
running
biking
weight lifting
two of the above
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Chapter 1. The Muscular System
Lesson 16.4: Matching
Name___________________ Class______________ Date________
Match each definition with the correct term.
Definitions
1.
2.
3.
4.
5.
6.
7.
_______ organelle that allows muscles to contract
_______ muscle found in the walls of internal organs except the heart
_______ tough connective tissue that attaches muscle to bone
_______ long, thin muscle cell
_______ muscle found in the walls of the heart
_______ protein filament that slides over another when a muscle contracts
_______ most common type of muscle in the body
Terms
a.
b.
c.
d.
e.
f.
g.
actin
cardiac muscle
smooth muscle
muscle fiber
tendon
myofibril
skeletal muscle
Lesson 16.4: Fill in the Blank
Name___________________ Class______________ Date________
Fill in the blank with the appropriate term.
1.
2.
3.
4.
5.
6.
7.
_____ are the main organs of the muscular system.
Muscles are composed primarily of cells called muscle _____.
_____ muscle is the only type of muscle tissue that is under conscious control.
You can straighten an arm bent at the elbow by contracting the _____ muscle.
Striated muscles include cardiac muscle and _____ muscle.
Myofibrils are made up of two types of proteins, called actin and _____.
Energy for muscle contractions comes from _____.
Lesson 16.4: Critical Writing
Name___________________ Class______________ Date________
Thoroughly answer the question below. Use appropriate academic vocabulary and clear and complete sentences.
Explain muscle contraction at a molecular level.
3