人拇长屈肌和拇长伸肌的肌纤维型构成及年龄差异

HISTOLOGICAL STUDY OF THE AV NODE,AV BUNDLE AND ITS BRANCHES OF HEART IN DOGS

采用尸检取材（死后２４ｈ内）共１７例，用肌球蛋白ＡＴＰ酶染色法，研究了不同年龄组得长屈肌和拇长伸肌的肌纤维型构成。结果表明，各年龄组肌纤维型比例明显不同，Ⅰ型纤维比例在少儿组较高，中青年组较低，到老年组又见增高。方差分析表明，年龄组之间存在显著差异。此外，在中青年组和老年组，拇长伸肌的Ⅰ型纤维比例显著高于拇长屈肌；而在少儿组，两肌之间无明显差异。本文讨论了肌纤维型构成与肌功能适应的关系。

The morphologic features of AV node,AV bundle and its branches were observed in 12 adult mongrel dogs by light microscopy.The size of AV node is 3.16 mm×2.10 mm×0.66 mm in size.A overlaid layer consisted of auricular muscle and connective tissue was found on the right side of AV node.AV node is consist of P cells and T cells.According to the architecture of the cells,the AV node might be divided into upper and lower nodes,and P cells exist mainly in the upper node.The AV bundle,originating from AV node and penetrating central fibrous body,is 6.56 mm in length.Clear boundary between AV node and AV bundle could not observed under microscope,and more P cells and Purkinje cells were seen in the bundle.In one case,a cluster of P-like cells was detected in the middle part of right bundle branches,it may be a morphologic basis for ventricular ectopic beating.