Download Moves the bones - Spring Branch ISD

Name ______________________________________________ Date _____________________ Period ____________
Study Guide: The Muscular System
Directions: Read pg. 352-356 in Prentice Hall Science Explorer. Answer the following
questions.
1. What is the function of the muscular system in your body?
Coordinates movement of your body.
2. Muscles can be classified as either voluntary or involuntary. If a muscle can be controlled by you, it is called
voluntary.
If you cannot control the movement of a muscle, it is known as an
involuntary muscle.
3. List the three types of muscles. Describe each type as either voluntary or involuntary.
a. Skeletal – voluntary
b. Smooth - involuntary
c. Cardiac - involuntary
4. What is the function of the skeletal muscle?
Moves the bones
5. Muscles are attached to bone by tendons. Bones are attached to other bones
by ligaments. (refer to page 350)
6. Look at Figure 14. Explain how skeletal muscles always work in pairs when they move a bone.
As one muscle of the pair contracts and pulls the bone, the second muscle relaxes.
Example: Biceps contract to raise the arm while the triceps relax.
7. Where do you find smooth muscle in the human body? Give two examples of smooth muscle.
It is found in the internal organs. Examples: stomach, intestines, blood vessels.
8. When you are sleeping, your food continues to move through your digestive tract. Explain how this can occur.
Your digestive tract contains smooth muscle. It is involuntary and works 24 hours a day.
9. What is the function of cardiac muscle? Why is this muscle especially strong?
It contracts and relaxes to pump blood throughout the body 24 hours a day.
10. A muscle does work when it contracts or gets shorter. Sit up straight in a chair with your feet on the floor. Slowly
bring your right leg up so that your leg is straight out. When you straighten your leg at the knee, one set of muscles
in the upper part of your leg
contracts.
This causes the bone of your lower leg to be pulled straight up. Muscles
always pull; they never push.
Now, slowly bring the leg down so that your right foot is on the floor again. When your leg moves down, the muscle
on the top of you upper leg relaxes and the muscles on the bottom of your upper leg contract.
11. Like skeletal muscle, the cardiac muscle of the heart contracts and relaxes. The heart contracts about 70 times a
minute during normal activity. It continues contracting at this rate for a lifetime.
a. How many times does the heart contract in an hour?
b. A day?
c. A year?
100,800
36,792,000
12. What causes a muscle cramp?
A lack of oxygen or nutrients.
13. How many muscles are in the human body?
650
4,200