Structure of the tendon connective tissue
Structure of the tendon connective tissue
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DOI：
10.1034/j.1600-0838.2000.010006312.x
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发表时间：
2000-12-01
影响因子：
4.1
通讯作者：
Kannus, P
中科院分区：
文献类型：
--
作者：
Kannus, P
肌腱由包埋在蛋白聚糖基质中的胶原蛋白（主要是I型胶原蛋白）和弹性蛋白组成，胶原蛋白占肌腱干重的65-80%，弹性蛋白约占肌腱干重的1-2%。这些元素是由成腱细胞和腱细胞产生的，它们是位于胶原纤维之间的细长的成纤维细胞和纤维细胞，并以复杂的层次结构组织起来以形成肌腱。可溶性原胶原分子形成交联以产生不溶性胶原分子，所述不溶性胶原分子然后逐渐聚集成微纤维，然后聚集成电子显微镜下清晰可见的单位，即胶原纤维。一束胶原纤维形成胶原纤维，这是肌腱的基本单位。结缔组织的一个很好的鞘叫做腱内体，包裹着每一个胶原纤维，并将纤维结合在一起。一束胶原纤维形成初级纤维束，一组初级纤维束形成次级纤维束。一组二级纤维束依次形成三级纤维束，三级纤维束组成肌腱。整个肌腱被一层精细的结缔组织鞘包围，称为腱外膜。肌腱纤维和纤维束的三维超微结构复杂。在一根胶原纤维中，原纤维不仅纵向取向，而且横向和水平取向。纵向纤维不仅平行，而且相互交叉，形成螺旋。一些单独的原纤维和原纤维基团形成螺旋型辫状物。肌腱的基本功能是将肌肉产生的力传递到骨骼，并以这种方式使关节运动成为可能。肌腱和肌腱纤维复杂的宏观和微观结构使其成为可能。在运动的各个阶段，肌腱不仅暴露于纵向，而且暴露于横向和旋转的优势。此外，他们必须准备承受直接的挫伤和压力。纤维的上述三维内部结构形成抵抗各个方向的力的缓冲介质，从而防止纤维的损坏和断开。
Tendons consist of collagen (mostly type I collagen) and elastin embedded in a proteoglycan-mater matrix with collagen accounting for 65-80% and elastin approximately 1-2% of the dry mass of the tendon. These elements are produced by tenoblasts and tenocytes, which are the elongated fibroblasts and fibrocytes that lie between the collagen fibers, and are organized in a complex hierarchical scheme to form the tendon proper. Soluble tropocollagen molecules form cross-links to create insoluble collagen molecules which then aggregate progressively into microfibrils and then into electronmicroscopically clearly visible units, the collagen fibrils. A bunch of collagen fibrils forms a collagen fiber, which is the basic unit of a tendon. A fine sheath of connective tissue called endotenon invests each collagen fiber and binds fibers together. A bunch of collagen fibers forms a primary fiber bundle, and a group of primary fiber bundles forms a secondary fiber bundle. A group of secondary fiber bundles, in turn, forms a tertiary bundle, and the tertiary bundles make up the tendon. The entire tendon is surrounded by a fine connective tissue sheath called epitenon. The three-dimensional ultrastructure of tendon fibers and fiber bundles is complex. Within one collagen fiber, the fibrils are oriented not only longitudinally but also transversely and horizontally. The longitudinal fibers do not run only parallel but also cross each other, forming spirals. Some of the individual fibrils and fibril groups form spiral-type plaits. The basic function of the tendon is to transmit the force created by the muscle to the bone, and, in this way, make joint movement possible. The complex macro- and microstructure of tendons and tendon fibers make this possible. During various phases of movements, the tendons are exposed not only to longitudinal but also to transversal and rotational fortes. In addition, they must be prepared to withstand direct contusions and pressures. The above-described three-dimensional internal structure of the fibers forms a buffer medium against forces of various directions, thus preventing damage and disconnection of the fibers.