江豚背部小齿的超微结构与功能

THE ULTRASTRUCTURE AND FUNCTION OF THE TUBERCLES ON THE BACK OF NEOPHOCAENA PHOCAENOIDES IN THE CHANGJIANG RIVER IN CHINA

  • 摘要: 长江江豚背部皮肤表面有一长条小齿,由1—3排组成。它是由表皮向体表突起而成。小齿区皮肤中的乳头深深伸入表皮,几达表面,它的高度在成体约占整个表皮厚度的70—80%,新生幼儿为84.6%。经研究,我们发现在小齿区皮肤中存在着大量类似于人类皮肤中的环层小体那样的被囊神经末梢和几种有鞘神经纤维束。根据这些结构,我们认为小齿是一种感觉器官,它并不能起到防止幼儿从母体背部滑落的作用。

     

    Abstract: There is a longitudinal string of tubercles, arranged in one to three rows, on the surface of the dorsal skin of Neophocaena phocaenoides in the Changjiang River. On the basis of our histological research, the tubercles are the projecting hillocks of the epidermis extending higher than the surface of the skin. In the tubercular area, the papillae insert deeply into the epidermis. Their height is 70—80% of the epidermis in the adults, 84.5% in 1ihe newborn animals. In recent study, we found that a lot of the encapsulated nerve endings similar to the pacinian corpuscle in human skin and some kinds of bundles of myelinated nerve fibres are present in the tubercular skin. According to these findings, we could refer the tubercles to a sensory organ rather than a structure for preventing the calf from slipping off.

     

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