Label the parts of the following diagram of the human eye and state the functions of those parts.

Explanation

i. Pupil: The pupil contracts or widens depending on the intensity of light incident on the eye.
ii. Ciliary muscles: They help the eye lens to adjust the focal length depending on the distance of the object by contracting or relaxing.
iii. Retina: It is the screen inside the human eye which contains light sensitive cells. Image of an object is formed on this screen.
iv. Eye lens/crystalline lens: The lens allows the light to focus onto the retina.
v. Optic nerve: The sensitive cells on retina get excited when light falls on them and generate electric signals. Optic nerve carries these signals to the brain.