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The epididymis (; plural: epididymides or ) is a tube that connects a testicle to a vas deferens in the male reproductive system. It is present in all male reptiles, birds, and mammals. It is a single, narrow, tightly-coiled tube (in adult humans, six to seven meters in length) connecting the efferent ducts from the rear of each testicle to its vas deferens. ==Structure== The epididymis can be divided into three main regions: * The head ((ラテン語:Caput)). The head of the epididymis receives spermatozoa via the efferent ducts of the mediastinium of the testis. It is characterized histologically by a thin myoepithelium. The concentration of the sperm here is dilute. * The body ((ラテン語:Corpus)) * The tail ((ラテン語:Cauda)). This has a thicker myoepithelium than the head region, as it is involved in absorbing fluid to make the sperm more concentrated. In reptiles, there is an additional canal between the testis and the head of the epididymis and which receives the various efferent ducts. This is, however, absent in all birds and mammals. 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Epididymis」の詳細全文を読む スポンサード リンク
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