Name________________________________Class____________________Date____________________

Answer KeyMUSCULAR SYSTEM

1. Bones move when muscles pull on them.2. The arm bends at the elbow.3. The arm straightens.4. a

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Name________________________________Class____________________Date____________________ACTIVE READING WORKSHEETS

SKELETAL, MUSCULAR, AND INTEGUMENTARY SYSTEMS

Muscular SystemRead the passage below, which covers topics from your textbook. Answer the questions that follow.

Most skeletal muscles are arranged in opposing pairs. One muscle in a pair moves a limb in one direction; the other muscle moves it in the opposite direction. Muscles move bones by pulling them, not pushing them. For example, when the biceps muscle contracts, the arm bends at the elbow. The biceps muscle is known as a flexor, a muscle that bends a joint. Contraction of the triceps muscle in the upper arm straightens the limb. The triceps muscle is an example of an extensor, a muscle that straightens a joint. To bring about a smooth movement, one muscle in a pair must relax while the opposing muscle contracts.

Read each question and write your answer in the space provided.SKILL: Recognizing Cause-and-Effect Relationships1. What causes bones to move?

________________________________________________________________2. What is the effect of contraction of the biceps muscle?

________________________________________________________________3. What is the effect of contraction of the triceps muscle?

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Circle the letter of the word that completes the analogy.4. Extensor is to straighten as flexor is to

a. bend.b. push.c. expand.d. Both (a) and (b)

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