The human eye is an organ that reacts to light and
has several purposes. As a sense organ, the mammalian eye allows for
vision.
Today we have learned about the main parts of the human eye.
First, we have noted those parts in a drawing of a section of the eye.
Then
we have defined the specific function of each part. For example, we have
learned that specialized cells located on the retina, called rods and cones cells,
allow for conscious light perception and vision including color differentiation
and the perception of depth.
The human eye can distinguish about ¡¡¡10 million colors!!!
The eye is not shaped like a perfect sphere. The smaller frontal unit,
transparent and more curved, called the cornea is linked to
the larger white unit called the sclera.
The iris is the colored circular structure concentrically
surrounding the center of the eye, the pupil, which appears to be
black. The size of the pupil, which controls the amount of light entering the
eye, is adjusted by the muscles of the iris.
Light enters the eye
through the cornea, then the pupil and then
through the lenscontrolled by cilliary muscles. Light
falling on the light-sensitive cells of the retina is converted into electrical
signals that are carried to the brain by the optic nerves.
Did you know that a device known as an ophthalmoscope is
used to see inside the eye?
