促进醛固酮分泌的因素是
A.血糖浓度增高
B.血Ca2+浓度降低
C.血K+浓度增高
D.循环血量增多
E.血Na+浓度增高
参考答案:C
大量无色的单一纤维,常完整并具窄管腔()
A.Bundles of partially lignified fibres with crystal sheaths
B.Numerous colourless single fibres, often whole with narrow lumen
C.Parenchymatous cells,fibres,and vessels
D.Starch granules present,fibres and sclereids absent
E.Fibres with crystal sheath containing calcium oxalate prisms