Z line(redirected from Z band)
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Any of the dark thin protein bands to which actin filaments are attached in a striated muscle fiber and that mark the boundaries of adjoining contractile units.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.