This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
Cornea gets its nourishment mainly from:September 2009 
Select and explain. 
A. Atmosphere, B. Aqueous humour, C. Vitreous humour, D. Corneal vessels
B: Aqueous humour
Answer: B: Aqueous humour 
Explanation: Ans. B: Aqueous humourCornea consists of five layers, staing from the outside: (1) the stratified squamous epithelium; (2) Bowman's layer; (3) the stroma (substantia propria); (4) Descemet's membrane; and (5) the endothelium.The cornea is avascular, receiving its nourishment by permeation through spaces between the lamellae. The sources of nourishment are the aqueous humour (90%), the tears and the limbal capillaries.The cornea is innervated by the long ciliary and other nerves of the surrounding conjunctiva, which are all branches of the ophthalmic division of the trigeminal nerve. Innervation is entirely sensory.