Biology 2010 Student Edition

Published by Prentice Hall
ISBN 10: 9780133669510
ISBN 13: 978-0-13366-951-0

Chapter 32, Skeletal, Muscular, and Integumentary Systems - Assessment - 32.2 The Muscular System - Understand Key Concepts - Page 942: 13



Work Step by Step

Myofibrils contain thick protein filaments called myosin and thin protein filaments called actin. Contraction of muscles involves the formation of cross-bridges between the actin and myosin filaments. The shape changes in the cross-bridges and pulls the actin fibers toward the middle of the sarcomere, thus shortening the fibers.
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