apical cap 中文意思是什麼
apical cap
解釋
頂體帽-
2. sperm ultrastructure the sperm is nonflagellated and composed of a main body in which including nucleus n apical cap and a little cytoplasm and a single spike extending from the convex surface of the apical cap, which consists of about twenty radial fibrillae on which exhibiting periodic cross - striations. the concave surface of the apical cap surrounds the little cytoplasm which is highly condensed and has n ' t any organella and sperm nucleus, which is uncondensed and composed of filamentous materials and many membrane - bound vesicles
外形呈圖釘樣，由主體部和棘突組成，主體部包括帽狀體、細胞質帶和精核。帽狀體由約20根輻射狀排列的纖絲組成，纖絲具橫紋。其凸面延伸成棘突，棘突內纖絲是帽狀體內纖絲的延續，亦具橫紋。 -
Calyptogen a layer of meristematic cells covering the root apical meristem in some plants ( e. g. grasses ) that gives rise to and maintains the root cap
根冠原：在一些植物中覆蓋根頂端分生組織的一層具有分生能力的細胞，根冠原可以產生和維持根冠。 -
At the beginning, the cytoplasm is evently distributed, then it is polar - distribution and at last it only remains between the apical cap and the sperm nucleus. during the period of spermatogonium, chromatin in the nucleus is in the shape of conglomeration and the nucleus is big ( i. e. the proportion of the nucleus to cytoplasm is bigger than spermatocyte ). at the stage of primary spermatocyte, chromatin accumulates to sc complexity. the nucleus of the mature sperm takes the shape of a plate and filmentous chromatins exist freely in uncondensed nucleus
精子發生過程中，細胞器由少到多，到最後解體；細胞質從均勻分佈，到精細胞期極性分佈，最後殘留于成熟精子的頂帽和精核之間；細胞核在精原細胞期，染色質異固縮，胞核大，即核質比大於后續的精母細胞；在初級精母細胞中，染色質凝聚為sc復合體，到成熟精子，精核呈碟狀，染色質呈絲狀游離于非濃縮的核中。
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