A morphometric study of the expansion of the chick area vasculosa in shell-less culture.

A morphometric evaluation, utilising a computerised system, was undertaken to quantify the growth of blood vessels in the chick area vasculosa, between the 2nd and the 5th incubation days. In this phase of embryonic growth the total length of the vascular tree for the arterial and venous systems alone, increases more (2.7 times) than the area occupied by the area vasculosa. Two main mechanisms might regulate the growth of vessels: the release of collaterals from the vessels 1.01-2 mm long and the lengthening of the vessels by 2.01-7 mm.