Answer
Assess ; 15.4:8
Labelling diagram of the human eye:
a. retina
b. choroid
c. sclera
d. optic nerve
e. fovea centralis
f. ciliary body
g. lens
h. iris
j. pupil
i. cornea
Work Step by Step
The retina is the light sensitive layer of the eye; it has rods and cones--cones are sensitive to bright light and color; rods are receptors for dim light.
Choroid. The choroid is the middle pigmented layer of the eye; it absorbs stray light
Sclera. This is the tough, white, outer protective coat of the eye.
Optic nerve. This is the nerve of vision; sensory fibers from the retina form the optic nerve which leads ultimately to the visual cortex.
Fovea centralis. This is the region of the retina in which cones are tightly packed. Light is directed to the fovea centralis when we look directly at an object.
Ciliary body. The ciliary body contains the ciliary muscle that controls the shape of the lens to facilitate near or far vision.
The lens is a translucent biconvex structure behind the iris of the eye. It changes its shape ( degree of concavity or sphericity) to help to focus light on the retina .
The iris regulates the size of the pupil through which light enters the eye.
Pupil. The pupil is the aperture in the iris through which light passes to reach the lens; the lens focuses the light on the retina.
Cornea. This is the clear front layer of the eye that covers pupil, iris, and anterior chamber. The cornea plays the most important role in refraction of light that enters the eye. Most visual refractive syndromes such as nearsightedness and farsightedness are due to imperfect curvature of the cornea. Fortunately, some corneal problems can be cured by corneal transplantation/grafting -- a comparatively simple surgical procedure.
