This document discusses the three types of muscle tissue in the human body: 1) Smooth muscle is found in organs like the digestive tract and is not under voluntary control. 2) Cardiac muscle is only found in the heart and is also not under voluntary control. 3) Skeletal muscle is attached to bones and can be consciously controlled to enable voluntary motion.

1. Name____________________________ Class__________________ Date __________
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Name____________________________ Class__________________ Date __________
Types of Muscle Tissue
Use the words below to identify each of the three types of muscle found in
the human body.
cardiac muscle skeletal muscle smooth muscle
Use the table to answer the questions. Circle the correct answer.
1. Which muscles can you consciously control?
smooth skeletal
2. Where in the body is cardiac muscle found?
Muscle Type Structure and Example
Function
smooth muscle Cells are spindle- muscles that move
shaped with one food through the
nucleus and no digestive tract
striation; muscles
are usually not
under voluntary
control.
cardiac muscle Cells are striated, heart muscle
with one or two
nuclei; muscle is
found in only one
place in the body;
it is generally not
under voluntary
control.
skeletal muscle Cells are large and muscles attached
striated and have to bones
many nuclei; muscles
are used for
voluntary motion.
in the heart

2. Name____________________________ Class__________________ Date __________
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Name____________________________ Class__________________ Date __________
Muscle Contraction
Skeletal muscle fibers are made up of thick and thin filaments
arranged in units called sarcomeres. The thick filaments contain
the protein myosin, and the thin ones contain the protein actin.
When a muscle contracts, cross-bridges form between the myosin
and actin fibers. The myosin fibers pull on the actin fibers. This
motion, repeated in many sarcomeres, causes a muscle to contract.
Use the words below to label the diagrams.
actin cross-bridges myosin sarcomere
Relaxed Muscle
Contracted Muscle
Z line Z line
Z line
sarcomere
myosin
actin
cross-bridges
Z line
Use the diagram to answer the question.
1. Describe how the position of the actin filaments changes
during muscle contraction.
The actin fibers move into the center of the sarcomere.

3. Name____________________________ Class__________________ Date __________
© Pearson Education, Inc., publishing as Pearson Prentice Hall.
361
Name____________________________ Class__________________ Date __________
Opposing Pairs
When you straighten or bend your arm, two muscles work
together: the biceps and triceps. The biceps is located on the inside
of your upper arm. The triceps is on the outside of your upper
arm. When one muscle is contracted, the other muscle is relaxed.
Label whether each muscle is contracted or relaxed.
Movement
Movement
Biceps relaxed
Triceps contracted
Biceps contracted
Triceps relaxed
Use the diagram to answer the questions.
1. Which muscle contracts when you bend your arm? Circle the
correct answer.
biceps triceps
2. Which muscle relaxes when you extend your arm? Circle the
correct answer.
biceps triceps
3. Which muscles are used in the controlled movement of holding
a tennis racket?
both biceps and triceps