房室束横断面大多为三角形，外包有疏松结缔组织鞘。
His's bundle surround by loose connective tissues, was mostly triangle in shape.
中柱包括从原形成层衍生而来的全部初生组织，由中柱鞘、韧质部和木质部组成。
The stele includes all primary tissues derived from the procambium consists of pericycle, phloem and xylem.
中柱包括从原形成层衍生而来的全部初生组织，由中柱鞘、韧质部和木质部组成。
The stele includes all primary tissues derived from the procambium consists of pericycle, phloem and xylem .
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