This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: JIPMER 2019, Subject name: Anatomy
Crystalline Lens is derived from (JIPMER May 2019) 
Select and explain. 
A. Surface ectoderm, B. Neuroectoderm, C. Mesoderm, D. Endoderm
A: Surface ectoderm
Answer: A: Surface ectoderm 
Explanation: - Eye ball have contribution from several structures - Neural plate ectoderm forms Neural tube form - CNS which have diencephalon pa of brain aExtension of diencephalon (optic sulcus) into eyeball form retina (optic cup) & optic nerve (optic stalk) - Neural plate ectoderm also forms - epithelium of ciliary body & iris muscle - Muscles of Iris - Sphincter pupillae, dilator pupillae - Eye ball have some contribution from surface ectoderm as well which gives Surface epithelium of cornea (1st layer) Eye lens - Most of derivatives in eyeball come from neural crest cells which gives Secondary mesoderm of eyeball - Forms sclera, choroid, ciliary body & Iris (not epithelium) - All other layers of cornea except 1st layer develops from N.C.C