Sarcoplasm


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Related to Sarcoplasm: myofibril

sarcoplasm

[′sär·kə‚plaz·əm]
(histology)
Hyaline, semifluid interfibrillar substance of striated muscle tissue.

Sarcoplasm

 

the cytoplasm of smooth-muscle cells and striated and myocardial muscle fibers. The matrix, or basic material, of sarcoplasm contains glycolytic enzymes and other globular proteins, for example, myoglobin; it also contains salts, polyphosphates, and glycogen, which is depleted during muscle contraction. Sarcoplasm surrounds nuclei and fills the space between myofibrils. It contains ribosomes, mitochondria (sarcosomes), and a complex system of membrane-bound vesicles, tubules, and cisterns, all of which are combined into a continuous sarcoplasmic reticulum.

The sarcoplasmic reticulum is divided into two parts. One part is oriented along the myofibrils and is equivalent to the endoplasmic reticulum found in other types of cells. The other part is oriented across a muscle fiber and forms the T system, which is a system that conducts impulses from the surface to deep within a muscle fiber and, in some places, changes into sarcolemma. The sarcoplasmic reticulum probably transmits excitation within a fiber. It also contains the Marsh factor, which inhibits the activity of the enzyme adenosine triphosphatase. The amount of sarcoplasm varies in different striated fibers: collagenous fibers contain little sarcoplasm, whereas red fibers contain a great deal.

L. V. DANILOVA

References in periodicals archive ?
The degeneration of motor endplates discussed above, and present in many SCS cases, has been attributed to [Ca.sup.2+] overload in the sarcoplasm and the concomitant activation of [Ca.sup.2+]-sensitive degradative enzymes (5), thus sparking the interest ofresearchers in making use and developing metho-dological approaches to assess [Ca.sup.2+] overloading in endplates (22, 51-53).
(156,157) These mutations allow excessive calcium release from the sarcoplasmic reticulum into the sarcoplasm, resulting in intense muscle contraction.
Abnormal Internal nucleus Fiber containing [greater than muscle tissue or equal to] 1 internally located nuclei (2 [micro]m or 8 pixels of sarcoplasm between nucleus and sarcolemma).
Muscle tissues had small, focal areas of sarcoplasm degeneration, hyalinization or lysis, with mild to moderate proliferation of sarcolemmal nuclei (Fig.
These have tubular mitochondria and a small number of sarcoplasmic reticula around the sarcolemma and some glycogen granules in the sarcoplasm (Fig.
The nuclei are normally located in the lateral luminal protrusions of the sarcoplasm. The karyoplasm is filled with condensed chromatin blocks, located predominantly under the plasma membrane, and with fine ly dispersed chromatin.
These included limited areas of elongated myocardial fibers, hypertrophied cardiomyocytes, and slight interstitial edema as well as small clusters of "wavy" myocytes with condensed sarcoplasm and preserved nuclei.
The morphology of the EDL muscle from the CTL group exhibited sarcoplasm with the presence of well-defined myofibrils and an organized Z-line (Fig.
Light microscopy of a vastus lateralis biopsy demonstrated ovoid organisms either free in the endomysium, within the myofiber sarcoplasm, or within macrophages in myofibers (Figure 1).
Sarcoplasmic proteins, localized in the sarcoplasm of the muscle fibers, are recognized to be soluble in water or in solutions of low ionic strength, whereas stromal proteins, such as collagen and elastin, are reported to remain insoluble in high-salt solutions [3].
Accordingly, Bekhit and Faustman [5] suggested that the principal chemical ingredient that affects meat color was myoglobin from sarcoplasm. Based on the distinctive reflectance spectra, myoglobin has been classified into three basic states: deoxymyoglobin (DMb), oxymyoglobin (OMb), and metmyoglobin (MMb) [6].