MRCP UK EXAMINATIONS

Detailed explanation-1: -Neuroectoderm also contributes as the source of the retina, posterior iris, and optic nerve. Surface ectoderm gives rise to the lens and corneal epithelium [6]. Mesoderm differentiates into vascular endothelium of the eye and the extraocular muscles [7].

Detailed explanation-2: -Iris and Ciliary Body The intrinsic muscles of the iris (sphincter pupillae and dilator pupillae) are derived from the surrounding neuroectoderm, whereas the ciliary muscle, the structure eventually responsible for changing the shape of the mature lens, is derived from invading neural crest cells.

Detailed explanation-3: -Embryonic Tissue Derivatives As you may recall from medical school, there are three primary germ layers: ectoderm, mesoderm, and endoderm. The eye and its surrounding tissues arise solely from ectoderm and mesoderm; there is no endoderm-derived tissue around the eye.