In this article we will discuss about the development of eyes in all vertebrates. The Optic Cup: The optic vesicles push outward until they reach the epidermis, displacing the intervening mesenchyme, so that they come into direct contact with the inner surface of the epidermis. Next, the external surface of the optic vesicle flattens out and invaginates inward, so that [...]
The neural crest at the time of its formation is represented by a mass of loose cells lying dorsal to the neural tube. Almost at once after the formation of the crest, the cells of which it consists start migrating in a lateral and ventral direction from the place of their origin. As the neural crest cells move, they form [...]
The cranial nerves of vertebrates, when compared with the spinal nerves, show a great diversity in configuration, distribution, and function and the same diversity can also be noted in their development in the embryo. To start with, the two most anterior nerve pairs, nerves I (olfactory) and II (optic), are completely different in nature and cannot be in any way [...]