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THE STRUCTURE OF THE HUMAN EYE
The shape of the eye is given by its three shells:
1. outer
2. middle
3. inner
The outer shell, or layer, consists of:
corneas
of the sclera (protein shell) (figure 38)
The sclera is dense, opaque, white in color, performs a protective function. In the
anterior part of the eyeball, the sclera passes into a transparent cornea.
Figure 38. Structure of the eye
The middle shell of the eye consists of:
the iris
of the ciliary body
of the choroid
The vascular membrane is adjacent throughout to the protein membrane, includes
many blood vessels that supply the eye with blood. At the level of the cornea, the
vascular membrane passes into the ciliary body, with which the lens is fixed in the
eyeball, and into the iris. The iris contains pigment, the amount and distribution of
which depends on the color of the eyes. Between the cornea and the iris is the anterior
chamber of the eye, filled with fluid.
In the center of the iris there is a hole – the pupil. Its diameter can change due to
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