Sarcomere


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sarcomere

[′sär·kə‚mir]
(histology)
One of the segments defined by Z disks in a skeletal muscle fibril.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Sarcomere

 

a muscle-fiber segment between two dark Z bands that is the main recurring structural unit of myofibrils. Each sarcomere includes a single dark anisotropic A band and two light isotropic I disks. In the middle of each sarcomere is a narrow light H band containing a dark central M band.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Initially, we have slided actin filaments on either side of A band in a single sarcomere toward its center.
As the relative depression of sarcomere shortening was high at frequencies above 4 Hz the frequency dependence of shortening was abolished.
reported that treatment of hESC-derived cardiomyocytes with phenylephrine (an [alpha]-adrenoceptor agonist) for 48 hours led to a 1.8-fold increase in cell size and better-organized sarcomere structure [43].
In concentric contractions, the myriad tiny impulses of mechanical energy generated by the active sarcomeres (in series, parallel or pinnate fibers) in a whole muscle, and stored in the various elastic elements, become combined and transmitted to attached tendons.
The sarcomere length was assessed laser diffraction technique [14].
"We postulate that longitudinal atrophy, in concert with the aforementioned cross-sectional atrophy, hampers spontaneous breathing trials in critically ill patients: during these efforts, end-expiratory lung volume is reduced, and the shortened diaphragm fibers are stretched to excessive sarcomere lengths," the authors write.
These striations do not display the typical sarcomere structure because of their lack of Z-disks, but they might display an intermediate stage between smooth muscle and striated muscle.
Calpain 3 is a calcium-dependent protease, whose biological functions include sarcomere assembly and remodeling, muscle membrane, and triad integrity maintenance, as well as participation in cell apoptosis.
Although the terminal boutons (TB) were reloaded with synaptic vesicles (panel A) the mitochondria (M) in the vicinity of the sole plate nucleus (N) are swollen; despite, mitochondria and sarcomere (S) ultrastructure are well organized indicating preserved muscle fibers morphology (panel B).
When a muscle undergoes contraction, overall muscle length becomes shorter due to sarcomere cross bridging and muscle-belly diameter increases.