Essay About Structure Of The Eye And Express Emotions

Structure of the Eye and Ear
Essay title: Structure of the Eye and Ear
iffany Goff
Margaret Jenkins
General psychology
7/11/04
Structures of the eye and ear
We use our ears for the hearing sense, and we use our eyes for vision.
Both are very important senses and would be hard to get along without.
We rely on hearing for communication, navigation, entertainment and many
other purposes
Now for our eyes we use them for vision, their like our own personal camera’s,
both have and use lens to focus on images.
The eyes respond to the visible spectrum, this spectrum is made up of
wavelengths of different sizes. The shorter waves produce a purple color, while
Longer wavelengths produce blue, yellow, green and orange, and the longest
Waves are red. Saturation, brightness, and hue all are components used in the
Visible spectrum.
More than half of the sensory receptors in the body happen to be
located in the eyes, also the cerebral cortex plays a large role in processing
Visual information.
Some accessory structures of the eye are: the eyelids, eyelashes, eyebrows,
Lacrimal apparatus, and the extrinsic eye muscles. The eyelids or (palpebrae)
Are used for shade, whether it’s for sleeping or from excessive light, or from
foreign objects that don’t belong in the eye. While the eyelids are protecting
The eye it also helps at the same time by spreading lubricates over the eyeballs.
The eyelashes help protect from foreign objects and perspiration, as well do the
Eyebrows . The Lacrimal apparatus is a group of small structures, when humans
Express emotions with tears, the Lacrimal apparatus helps to produce and then
Drain those tears away. There are six extrinsic eye muscles to help move each
Eye; the superior rectus, inferior rectus, lateral rectus, medial rectus, superior
oblique and inferior oblique. Circuits in the brain stem and cerebellum tell these
muscles what to do.
The structure of the eye begins with the fibrous tunic, vascular tunic
And the retina. These are all on the wall of the eyeball, the fibrous tunic consist of
the cornea and the sclera. The cornea is what covers the iris, and is the
outermost layer of the eye through which light passes. The sclera or the “white”
of the eye, this is what gives form to the eyeball. The vascular tunic has three
parts to it; the choroids, ciliary body, and the iris. The choroids is what provides
nutrients to the surface of the retina. The ciliary body consist of ciliary muscle
and the iris which is the colored part of the eye, it regulates the amount of light
entering the vitreous chamber, through the pupil.
The inner coat and the beginning of the visual pathway is the retina, the fovea
defines the center of the retina, and is the region of highest visual activity.