THE ORIGIN OF THE EYEBALL
THE CORNEA:
The formation of the cornea is induced by the lens and the optic cup. The corneal
epithelium forms from the surface ectoderm. The substantia propria is formed from
mesenchyme. The endothelium covering it's posterior surface is derived from the neural
crest.
Bowman's membrane, Which lies imminently beneath the basal lamina of the corneal
epithelium, is formed from mesenchyme. Descemet's membrane Which is the basement
membrane of the endothelial cells, is synthesized by the endothelial cells.
THE SCLERA:
The sclera, the outer tough fibrous coat of the eyeball, is formed from a
condensation of the mesenchyme outside the optic cup. It first forms near the future insertion
of the rectus muscles.
THE CHOROID:
The choroid, the inner vascular coat of the eyeball, develops early and is formed
from the mesenchyme surrounding the optic vesicle.
THE EXTRAOCULAR MUSCLES:
The four rectus muscles and the superior and inferior oblique muscles of the eyeball
are formed from the mesenchyme in the region of the developing eyeball. Originally
represented as a single mass of mesenchyme, they later separate into distinct muscles, first
at their insertions and later still at their origins. The levator palpebrae superioris is formed
last, splitting off from the mesenchyme that forms the superior rectus muscles. During
development the extraocular muscles become associated with the third, fourth, and sixth
cranial nerves.
THE CORNEA:
The formation of the cornea is induced by the lens and the optic cup. The corneal
epithelium forms from the surface ectoderm. The substantia propria is formed from
mesenchyme. The endothelium covering it's posterior surface is derived from the neural
crest.
Bowman's membrane, Which lies imminently beneath the basal lamina of the corneal
epithelium, is formed from mesenchyme. Descemet's membrane Which is the basement
membrane of the endothelial cells, is synthesized by the endothelial cells.
THE SCLERA:
The sclera, the outer tough fibrous coat of the eyeball, is formed from a
condensation of the mesenchyme outside the optic cup. It first forms near the future insertion
of the rectus muscles.
THE CHOROID:
The choroid, the inner vascular coat of the eyeball, develops early and is formed
from the mesenchyme surrounding the optic vesicle.
THE EXTRAOCULAR MUSCLES:
The four rectus muscles and the superior and inferior oblique muscles of the eyeball
are formed from the mesenchyme in the region of the developing eyeball. Originally
represented as a single mass of mesenchyme, they later separate into distinct muscles, first
at their insertions and later still at their origins. The levator palpebrae superioris is formed
last, splitting off from the mesenchyme that forms the superior rectus muscles. During
development the extraocular muscles become associated with the third, fourth, and sixth
cranial nerves.
