著者

兵頭 政光 相原 隆一 河北 誠二 湯本 英二

出版者

日本喉頭科学会

雑誌

喉頭 (ISSN:09156127)

巻号頁・発行日

vol.7, no.1, pp.64-70, 1995-06-01 (Released:2012-09-24)

参考文献数

14

被引用文献数

2 5

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The hypopharyngeal constrictor muscle consists of the thyropharyngeal (TP) and cricopharyngeal (CP) muscles. These two muscles cooperatively and, in a sense, competitively work at the pharyngeal swallowing stage. Contraction of the TP muscle drives bolus into the esophagus, while the CP muscle ralaxes and allows the bolus to pass through the upper esophageal sphincter which is made by a contraction of the CP muscle.We investigated histochemical properties of these two muscles. Acetylcholine esterase stain showed that the neuromuscular junctions of the CP muscle were scattered in the horizontal direction compaired to those of the TP muscle. Glycogen depletion test showed that the glycogen-negative muscle fibers were distributed uniformly througout the TP muscle, while those of the CP muscle decreased in number from the stimulated side toward the unstimulated side. These results suggested that the CP muscle fibers terminate in the belly of the muscle, and that length of the CP muscle fiber is not uniform. Actomyosin ATPase stain revealed that type 2B fiber was predominant in the TP muscle, while type 1 fiber was predominant in the CP muscle. The mean diameter of the TP muscle fibers was larger than that of the CP muscle.In conclusion, the histochemical properties of the TP and CP muscle showed a great contrast to each other. But these different properties gradually change around the border of the two muscles.