Density of cells and mitoses in the upper limb primordium of the chick embryo during days 3 and 4 of incubation.
3 groups of Embryos (Hamburger-Hamilton's stages 17--18 HH 21, HH 23) were used for assessing the density of cells and density of mitoses per tissue volume unit in the upper limb buds of the chick embryos. The extremities were studies as a whole, as were their individual parts which had been precisely defined before. We disclosed that 1. The density of cells in the whole extremity descreases during 3 to 4 of incubation. 2. Various parts of the limb bud differed as regards the density of cells. In group II (HH 21), the cell density was highest in the ventral axial part, being lowest in the axial one. In group III (HH 23) the differences disappeared, the most dense tissue being, paradoxically, in the axial part. 3. The density of mitoses decreased during the period studied, the differences between various components of the limb primordium being nonsignificant.
D000818:Animals; D002642:Chick Embryo / Q000166:cytology* / Q000254:growth & development; D005121:Extremities / Q000196:embryology*; D008938:Mitosis