Question

what statement is wrong about conjunctiva?
A) Ectodermal origin
B) Present on the central part of the cornea
C) Vascular
D) Covers the anterior part of the sclera

Answer 1

Hint:Human eyeball is approximately globe-shaped. Except for the anterior one-sixth, the five-sixths of the eyeball is situated in a bony cavity known as an orbital cavity or eye socket.

Complete answer:
Eyeball is made up of two segments, an anterior part, and a posterior part. The anterior part is small and forms one-sixth of the eyeball. The posterior part is larger and forms five-sixths of the eyeball. The posterior wall of this part is lined by the light-sensitive structure called the retina. Conjunctiva is a thin mucus membrane, which covers the exposed part of the eye. After covering the anterior surface, the conjunctiva is reflected in the inner surfaces of eyelids. Conjunctiva is highly vascular and ectodermal in origin. The sclera is the white fibrous outer layer of the eyeball, that covers the posterior five-sixths of the eye. Anteriorly it is continuous with the cornea. Conjunctiva is absent in the central part of the cornea.

Hence, the correct answer is ‘B’ i.e, Present on the central part of the cornea is the wrong statement about conjunctiva.

Note:Cornea is not vascularized. Therefore, it derives its nourishment mainly from the aqueous humor. The Center of the cornea is more sensitive to pain because of the rich supply of free nerve endings.