Comparative histological study of aorta in man and sheep

This study has been done to compare between the different parts of human aorta and the same parts of the sheep aorta. It was found that the lining epithelium in the human aorta is thinner than that of the sheep which could be attributed to that the blood pressure in the fatter is higher than that of the first. Also the smooth muscle cells in the sheep aorta were arranged in longitudinal column specially in the distal parts. It could be suggested that this arrangement is to sooth the contractility of the circular muscle layer and to act as a shifter around the circular layer to minimise the effect of gravity on that layer

Differentiation of the cortical plate in the cerebral cortex of rabbit

The cortical plate could be distinguished at the age of 16 days prenatally. Differentiation of the cortical plate occurred with advancement of age leading to the formation of the different layers of the cortex by the following sequence of changes.a-Differentiation began and proceeded most rapidly after the arrival of neuroblasts to the other part of the cortical plate b-Somata of old elements appeared to move to inner levels of the cortical c-The terminal denderitic arbors of pyramidal cells remained, in the marginal lamina while the apical processes grew progressively longer

Origin of the cortical plate of the cerebral cortex of rabbit

This sutdy revealed that: 1. The cortical plate could be distinguished at the age of the 16th day prenatally in rabbit embryo. 2. Formation of the cortical plate was due to continuous migratory process of neuroblasts from the neuro-epithelial cells in the matrix lamina