What is the function in human eye ? explain the following:
a) Sclera
b) Cornea
c) iris
d) choroid
Answers
Answer:
1.The sclera is the opaque, fibrous, tough, protective outer layer of the eye (“white of the eye”) that is directly continuous with the cornea in front and with the sheath covering the optic nerve behind. The sclera provides protection and form.
2.Light enters the eye through the cornea, the clear, curved layer in front of the iris and pupil. The cornea serves as a protective covering for the front of the eye and also helps focus light on the retina at the back of the eye.
3.Together with the pupil, the iris is responsible for regulating the amount of light that gets into the eye. Too much or too little light can hamper vision. The muscular iris moves to shrink the pupil if there is too much light and widen it if there is not enough.
4.Choroid. The vascular (major blood vessel), central layer of the eye lying between the retina and sclera. Its function is to provide nourishment to the outer layers of the retina through blood vessels. It is part of the uveal tract.
Answer:
A The sclera, also known as the white of the eye or, in older literature, as the tunica albuginea oculi, is the opaque, fibrous, protective, outer layer of the human eye containing mainly collagen and some elastic fiber.
B Cornea: The front transparent part of the sclera is called cornea. Light enters the eye through the cornea.
C The circular, colored curtain of the eye.
D The choroid has several functions: Its vasculature is the major supply for the outer retina; impairment of the flow of oxygen from choroid to retina may cause Age-Related Macular Degeneration.
