Structure and Functions of the Ear and the Eye

Structureand Functions of the Ear and the Eye

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Structureand Functions of the Ear and the Eye

Oneof the key organs in a human’s body is the ear. With the organdivided into external, middle, and inner portions, each of the partsplays an important role for the effective functioning of the earsystem. The ear is responsible for the sensory perception of soundwhich in turn affects higher brain functions such as thought, memory,emotion, and language comprehension. The ear promotes motor functionsby maintaining balance and position of body organs (Asha, 2015). Itis divided into 3 parts: external, middle and inner ear. The externalear structures include the pinna and external auditory meatus. Theexternal ear structures collect sound waves and focus the energy onthe eardrum (Seeley, Tate &amp Stephens, 2008). The externalauditory canal contains hairs and ceruminous glands, which secretecerumen which traps dust and other materials preventing them fromreaching the middle ear.

Themiddle ear contains the eardrum and three ear ossicles: Malleus,incus, and stapes (Seeley, Tate &amp Stephens, 2008). Sound waveshit the eardrum causing it to move back and forth. The ossicles movewith the eardrum and convert sound energy to mechanical energy andthen transfer the vibrations to the inner ear (Rogers, 2012). Themiddle ear also known as the ‘Eustachian tube’ joins the middleear with the nasopharynx. The tube is responsible for aeration in themiddle ear and equalization of pressures.

Theinner ear contains the sensory organs responsible for hearing andbalance by generating impulses for interpretation by the brain. Thestructures contained in the inner ear include the Cochlea, organ ofCorti, which holds the nerve receptors, the vestibular system, andthe auditory nerve (Seeley, Tate &amp Stephens, 2008).. The cochlearensures hearing by converting mechanical vibrations to nerveimpulses. The vestibular system coordinates movement and ensuresbalance.

Otitismedia is a major pathological affliction of the ear. Otitis media isthe inflammation of the middle ear mainly caused by viral orbacterial infections. The organisms invade the middle ear, causinginflammation, edema, and draining of pus (Rogers, 2012). The fluidcauses increased pressure in the ear and bulges the ear drum. Theblockage of sound waves can lead to deafness. Otitis media is treatedusing antibiotics with penicillin being the preferred drug of choice.Analgesics should be given as well to reduce pain.

Theeye functions to transmit light through the lens to the retina,creating an image of the surroundings. It plays a crucial role in theperception of color and detail. The eye has different structures. Theeye is made up of the eyeball, muscles, nerves, and glands (Seeley,Tate &amp Stephens, 2008). The muscles are responsible for eyemovement and closure of the eyelids. The lacrimal glands secretetears which act as a lubricant and prevent infections. The sclera,which is the white part of the eye protects the eyes and maintainsits shape. The cornea is the refractive media of the eye.

Theconjunctiva lines the inner eyelid protecting the eyeball bylubricating it. The eyeball has three coats: the outer coat containsthe sclera and the cornea. The middle coat has the Iris, ciliarybody, and choroids that adjust the lens. The lens reflects andconcentrates the light on the retina. The inner coat that comprisesthe retina also contains photoreceptors that sense light (Yanoff,Duker &amp Augsburger, 2009). The optic nerve then transmits thenerve impulses to the brain, which interprets it to a certain image.

Cataractis a major eye condition that can lead to blindness. It results fromthe lens becoming opaque, thus, shielding rays of light from reachingthe retina. This causes visual impairment or blindness, which isnormally gradual and painless (Yanoff, Duker &amp Augsburger, 2009).Cataract is treated by intraocular lens replacement done surgically.The opaque lens is removed surgically and is replaced with asynthetic one. The synthetic lens allows light to reach the retina,therefore, restoring the sight.

References

Asha.(2015). Hearingand Balance.Retrieved 5 November 2015, from http://www.asha.org/public/hearing/

Rogers,K. (2012). Ear,nose, and throat.New York, NY: Britannica Educational Pub. In association with RosenEducational Services.

Seeley,R., Tate, P., &amp Stephens, T. (2008). Anatomy&amp physiology.Dubuque, IA: McGraw-Hill.

Yanoff,M., Duker, J., &amp Augsburger, J. (2009). Ophthalmology.[Edinburgh]: Mosby Elsevier.