External Auditory Canal And The Middle Ear example essay topic

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 (palpebrate) 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 Our ears for this. The anatomy of the ear is broken down into three main regions; The external ear, the middle ear, and the internal ear.

To start with, the external or outer ear consist of the external auditory canal the eardrum and the pinna Which is the flap of skin that you usually hang your earrings from. The eardrum or Tympanic membrane, located between the external auditory canal and the middle ear is covered by the epidermis skin. The middle portion of the ear is lined by epithelium and is separated from the external ear by the eardrum and from the internal ear by The oval window. The three smallest bones in the body are located in the middle portion of the ear their called the auditory ossicles. Located in the anterior wall of the middle ear is an opening called the auditory tube. During Yawning or swallowing it opens to allow air to pass through back and fourth until Ear pressure equals atmospheric pressure when their balanced the eardrum vibrates freely as sound waves hit it.

Problems resulting from unequal pressure Consist of very intense pain, hearing damage, and ringing in the ears. The third part of the ear is the internal or inner ear, because there are so many different and complicated canals going through the inner ear, it consist of two divisions called the outer bony labyrinth and inner Membranous labyrinth. At the end of each canal is a swollen enlargement Called the ampulla and that is what communicates with the vestibule. Now, how sound travels through all of these parts, starts with Sound waves.

Sound waves are varying types of pressure traveling through the air in the same direction. They start from an object's vibrations, and each sound from the vibration's has a different frequency. Frequency is also known as pitch, The higher the pitch the larger the intensity is on the hair cells in the cochlea, This could result in hearing loss.