Histologically, they have a papillary architecture with slender fibrovascular cores and rare basal mitoses.
Nuclear pleomorphism is usually minimal and mitoses are infrequently seen.
However, a cambium layer, abnormal mitoses and nuclear pleomorphism is not seen.
More important, mitoses are often numerous and distinctly atypical; anarchic multiple spindles may be seen and sometimes appear as tripolar or quadripolar forms.
Quite clearly here, villus length had not yet fallen to its maximum (below 200 mm), crypt hyperplasia and mitoses per villus-crypt unit had not increased to their respective maxima.
However, the dynamics of this decrease differs in the halves obtained by bisection of the 1-cell embryos and blastomeres in the first and second mitoses.
Duration of mouse embryo mitoses embryos.
The number of mitoses in naive animals was 9.31 ^ 0.48 per villus-crypt unit, and slightly higher at 10.9 ^ 0.5 in infected animals.
