(a) Draw a labelled diagram of the human eye. Label the following parts on this diagram: Cornea, Iris, Pupil, Ciliary muscles, Eye-lens, Retina, Optic nerve and Blind spot.
(b) What are the functions of the following parts of the eye?
(i) Iris (ii) Eye-lens (iii) Ciliary muscles (iv) Retina (v) Optic nerve
(i) Iris - The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupil and thus the amount of light reaching the retina.
(ii) Eye - lens - The lens is located in the eye. By changing its shape, the lens changes the focal distance of the eye.
(iii) Ciliary Muscles - The ciliary muscle is a ring of smooth muscle in the eye's middle layer (vascular layer) that controls accommodation for viewing objects at varying distances and regulates the flow of aqueous humour
(iv) Retina - The retina is a thin layer of tissue that lines the back of the eye on the inside. It is located near the optic nerve. The purpose of the retina is to receive light that the lens has focused, convert the light into neural signals, and send these signals on to the brain for visual recognition.
(v) Optic nerve - Optic nerve is to transfer visual information from the retina to the vision centers of the brain via electrical impulses.