Explain the functions of the following parts of the eye: (i) Cornea (ii) iris (iii) pupil (iv) ciliary muscles (v) crystalline lens
Answers
Answer:
Explanation:
1. cornea - it provides 67 % of eye's focusing power.
2. Iris - It controles the size of the pupil.
3. Crystalline lens - it is the central part of the eye that faciliates the image formation.
4. Cilliary Muscles- They hold the lens in position and help in modifying the curvature of the lens.
5. pupil-The pupil is a hole located in the center of the iris of the eye that allows light to strike the retina. It appears black because light rays entering the pupil are either absorbed by the tissues inside the eye directly, or absorbed after diffuse reflections within the eye that mostly miss exiting the narrow pupil.
(i) Cornea ⇒ Cornea is a protective transparent layer in front of the human eye through which light enters. It completely lacks blood vessels due to which cornea transplant is never rejected and successful.
(ii) Iris ⇒It is a flat and coloured portion of the eye present just behind the cornea, it controls the amount of light entering the eye by regulating the size of pupil.
(iii) pupil ⇒The opening through which light reflected from the objects enter our eyes.
(iv) Ciliary muscles ⇒ It is responsible for changing the shape of eye lens for adjusting the focal length to enable us seeing objects at different distances.
(v) Crystalline lens ⇒Its fuction is similar to convex lens, which is to bend the rays of light coming inside the eye and to focus them on the retina.