Z line. The American Heritage® Dictionary of the English Language: Fourth Edition. 2000.

The American Heritage^® Dictionary of the English Language: Fourth Edition. 2000.

Z line

NOUN:	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.


The American Heritage^® Dictionary of the English Language, Fourth Edition. Copyright © 2000 by Houghton Mifflin Company. Published by the Houghton Mifflin Company. All rights reserved.