黄毛鼠精子尾部主段超微结构

黄毛鼠精子尾主段具有纤维鞘。纤维鞘具背腹两条纵柱和环肋。纤维鞘之内分布着从中段延伸下来的外周致密纤维。在主段的近中段端，有９条外周致密纤维。随后，外周致密纤维逐渐变细，且逐一终止，在９条外周致密纤维中，最早终止的是Ｆ８，随后的终止顺序是Ｆ３、Ｆ４、Ｆ７、Ｆ２、Ｆ９、Ｆ５、Ｆ６、Ｆ１。在主段的近末段端，没有外周致密纤维。根据外周致密纤维的数量，可以将主段分为１０个区域。从近中段端至近末段端，这１０个

THE ULTRASTRUCTURE OF THE PRINCIPAL PIECE OF THE SPERM TAIL OF RATTUS RATTOIDES

There is a fibrous sheath in the principal piece of the sperm tail of rat (Rattus rattoides). The fibrous sheath consists of dorsal longitudinal column, ventral longitudinal column,and circumferential ribs. Within the fibrous sheath, there are outer dense fibers which come from the midpiece of the tail. At the proximal end of the principal piece, there are nine outer dense fibers which taper and terminate one by one. The outer dense fiber which terminates earliestly is F8. The second,F3;the third,F4;the fourth,F7;the fifth,F2;the sixth, F9; the seventh,F5;the eigth,F6; and the last one terminating is F1. At the distal end of the principal piece, there is no outer dense fiber. Therefore,from the proximal end to the distal end,the principal piece can be divided into 10 regions according to the orders of the outer dense fibers, i. e. 9-fiber region,8-fiber region, 7-fiber region,6-fiber region,5-fiber region,4-fiber region, 3-fiber region,2-fiber region, 1-fiber region,and 0-fiber region. Among the 10 regions,the 7-fiber region is the longest. At the proximal end of the principal piece, there are satellite fibrils among the outer dense fibers.