Functional morphology of force transmission in skeletal muscle. A brief review.
Functional morphology of force transmission in skeletal muscle. A brief review.
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DOI：
10.1159/000147459
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
J. Trotter
中科院分区：
文献类型：
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作者：
J. Trotter
肌肉的收缩蛋白在加速、减速或维持骨骼元素的位置方面所做的工作需要张力在纤维的表面膜上的有效传递。最广泛研究的张力传递部位是肌纤维的末端，在那里它们接触结缔组织或上皮组织。在大多数动物中，无论门，肌纤维末端特征性地折叠，产生显著降低施加到细胞膜上的应力的绝对值的连接界面，确保细胞膜上的主要应力矢量是剪切而不是张力，并且最小化应力集中。不同动物的肌肉-肌腱连接（MTJs）在形态和分子上的相似性表明，在肌肉纤维和不同物理特性的组织之间建立强粘合剂关节的问题对于所有肌肉来说基本上是相同的，并且解决方案在进化的早期就出现了。除了那些发生在纤维接触不同组织处的肌纤维末端之外，还有肌内纤维末端，其由类似于心肌的筋膜粘附体的折叠的细胞-细胞连接或逐渐变细的纤维末端组成。这两种肌内末端都出现在脊椎动物的肌肉中，这些肌肉中的单个肌纤维太短，无法从起源肌腱到达附着肌腱。在纤维末端逐渐变细的串联纤维肌肉中，张力从收缩蛋白质穿过纤维膜传递到肌内膜胶原原纤维。这些肌肉的肌内膜是一个基本的系列弹性元件。现有的证据表明，张力传递是肌肉细胞表面的一般性质，并且特定的连接形态是肌肉细胞与它们粘附的组织之间的动态相互作用的结果。
The work done by the contractile proteins of muscle in accelerating, decelerating, or maintaining the positions of skeletal elements requires the efficient transmission of tension across the surface membranes of the fibers. The most widely studied sites of tension transmission are the ends of muscle fibers where they contact either connective or epithelial tissues. In most animals, regardless of phylum, muscle fiber ends are characteristically folded, producing a junctional interface that significantly reduces the absolute value of stress applied to the cell membrane, insures that the principle stress vector at the cell membrane is shear rather than tension, and minimizes stress concentrations. The morphological and molecular similarities of muscle-tendon junctions (MTJs) in different animals suggest that the problem of creating a strong adhesive joint between a muscle fiber and a tissue of dissimilar physical properties is essentially the same for all muscles, and that the solution arose early in evolution. In addition to those muscle fiber ends that occur where fibers contact dissimilar tissues, there are intramuscular fiber terminations that consist either of folded cell-cell junctions similar to the fasciae adherentes of cardiac muscle, or of gradually tapering fiber ends. Both sorts of intramuscular ends occur in those vertebrate muscles in which the individual muscle fibers are too short to reach from the tendon of origin to the tendon of insertion. In series-fibered muscles in which the fiber ends are tapered, tension is transmitted from contractile proteins to endomysial collagen fibrils across the fiber membranes. The endomysium of such muscles is an essential series-elastic element. The existing evidence suggests that tension transmission is a general property of muscle cell surfaces, and that specific junctional morphologies are the results of dynamic interactions between muscle cells and the tissues to which they adhere.