Structure of the Eye and Ear

Topics: Eye, Ear, Auditory system Pages: 6 (961 words) Published: July 22, 2004
iffany Goff
Margaret Jenkins
General psychology

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.

Another structure of the eye is the lens, it's located behind the iris

And the pupil. This is the internal focusing element of the eye, and like layers of

An onion the protein called crystalline is arranged and that is what makes up the

Lens. As people get older with age, the lens becomes less flexible and not easily

to accommodate.

The more larger cavity of the eye is known as the vitreous

Chamber, and within the chamber is the vitreous body. The eye happens to be

Under pressure and that process is called intraocular pressure and this keeps the Eyeball from collapsing. As it was stated earlier the eye is like our own

personal camera, to understand how the eye forms clear images of different

Objects on the retina we must observe three different processes. Refraction by

the lens and cornea. The change in the shape of the lens, and the condition of

The pupil.

Our other very Important sense we have is hearing, and we use

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