Question

write the function of pupil, iris, eye lens, Retina,ciliary muscles.

Answer 1

It controls the amount of light that enters theeye. Lens: Behind the pupil, there is a transparent structure called a lens. By the action of ciliary muscles, it changes its shape to focus light on the retina. It becomes thinner to focus distant objects and becomes thicker to focus nearby objects.

Answer 2

pupil=pupil is a small aperture at the center of the iris. it regulates and controls the amount of light entering the eye.
iris =behind the cornea there is a dark muscular diaphgram that controls the size of pupil.
eye lens=behind the pupil in the eye, there is a biconvex lens. it is held by muscle fibers in positions. the lens divids the eyeball in two chambers.
retina is the innermost layer of human eye which is sensitive to the stimulus of light.
ciliary muscles =The ciliary muscles control the focal length of eye lens. when ciliary muscle contract, the eye lens become thin and its focal length increases. when the ciliary muscle relax,the eye lens become thick and its focal length decreses. so, the ciliary muscle are associated with power of accomodation of human eye.
hope it helps you