Functioning Organs of Vision |
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eye and ear |
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Functional Process of the Eye |
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(1)an image is formed on the retina; (2)the rods and cones are stimulated; (3)nerve impulses are conducted to the brain |
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Eyeball |
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composed of the sclera, the choroid, and the retina, and is connected to the brain by optic nerve |
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Sclera |
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external production |
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Cornea |
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light refraction |
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Choroid |
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middle layer of the tissue |
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Ciliary Body |
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secretion of vitreous fluid |
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Iris |
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color portion |
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Retina |
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back of eye, responsible for night vision |
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Rods |
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means of distinguishing light from dark, and perceiving shape and movement |
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Cones |
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color vision |
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Conjunctiva |
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pink area under eyelid |
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Anterior Chambers |
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space between the iris |
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Aqueous Humor |
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the fluid occupying both the anterior and posterior chambers |
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Vitreous Humar |
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jellylike fluid; it maintains the globular shape of the eyeball and facilitates the refractions of images |
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Internal lens of the eye |
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is elastic and therefore can focus images whether viewed close or at a distance |
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Key to sight |
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light ray |
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Extrinsic muscle |
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each eye has six extrinsic muscles that control the movements of the eye; these muscles pull on the eyeballs, making the two move together to converge on the visual field |
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Symptoms and signs of eye disorders |
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some eye disorders are signs of systemic diseases, such as hypertension, diabetes mellitus, or certain autoimmune arthritic diseases. Common symptoms are: Redness of the eye, pain, itching, or burning in or around the eye, swollen red eyelids, drainage from the eyes, lesions/sores in or around the eyes, visual disturbances, unequal pupils, sudden loss of vision, persistent pain |
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Opthamologist |
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study every aspect of your eye |
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Tests to identify eye disorders |
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eye charts, visual field tests, tonometry, eye cultures, dilation, electronystamography (ENG), electroretinography, fluorecein angiography |
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Refractive disorders |
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being unable to focus light effectively |
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Hyperopia (Farsightedness) |
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occurs when light that enters the eye is focused behind the retina rather than on the retina |
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Myopia (Nearsightedness) |
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the result of light rays entering the eye being focused in front of the retina, causing vision to be blurred |
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Astigmatism |
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an irregular focusing of the light rays entering the eye |
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Presbyopia |
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the inability of the internal lens of the eye to focus and then refocus quickly to accommodate variations in distance because of gradual loss of muscle and lens elasticity |
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Nystagmus |
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involuntary eye movement |
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Strabismus (cross eyed, lazy eye) |
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a visual defect of misalignment; failure of eyes to look in same direction |
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Hordeolum (sty) |
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inflammatory infections of the sebaceous glands of the eye lids |
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Hordeolum (sty) ETIOLOGY |
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often a result of a staphylococcal infection and can be associated with and secondary to blepharitis |
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Keratitis |
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inflammation of cornea |
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Keratitis ETIOLOGY |
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herpes, bacteria/fungi, contact lens wear, dry air, intense light |
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Blepharitis |
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inflammation of the eyelids involving hair follicles and glands |
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Blepharitis ETIOLOGY |
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the ulcerative form -staphyloccoal infection. nonulcerative-allergies |
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Entropian |
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eyelid margin go inward |
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Ectropian |
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eyelid margin go outward |
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Blepharoptosis |
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drooping of the upper eyelid |
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Conjunctivitis |
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inflammation of the conjunctiva |
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Conjunctivitis ETIOLOGY |
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allergies, chemicals |
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Cataract |
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when the natural lens of the eye becomes opacified |
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Cataract SYMPTOMS AND SIGNS |
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deterioration of vision |
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Cataract ETIOLOGY |
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aging process, congenital, ocular trauma, drug toxicity, systematic disease |
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Glaucoma |
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damage to the optic nerve |
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Glaucoma RESULTS |
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blindness |
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Diabetic Retinopathy |
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disorder of the retinal blood vessels |
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Diabetic Retinopathy SYMPTOMS AND SIGNS |
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micro aneurysm, hemorrhages, dilation of retinal veins, formation of abnormal new vessels |
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Diabetic Retinopathy ETIOLOGY |
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usually occurs 8 to 10 years after diagnosis of diabetes |
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Cancer of the eye |
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may involve the globe, the orbit, the optic nerve, or the eyelids |
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Functioning organs of hearing |
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the outer, the middle, the inner |
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Organ of hearing and balance |
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labyrinth |
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Outer section Parts |
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external ear (pinna or auricle), external auditory canal |
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Outer section Function |
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to collect sound waves, or vibrations, from the air or environment and channel them to tympanic membrane (eardrum), which then begins to vibrate |
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Middle section Parts |
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ear drum, 3 little bones (malleus, incus, stapes) |
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Middle section Function |
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receives the sound waves from the vibrating ear drum and relays them along the three bones to the oval window |
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Inner section Parts |
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cochlea and the labyrinth |
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Inner section Function |
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responsible for maintaining balance |
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Common signs and symptoms of ear disorders |
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hearing loss, ear pain or pressure, tinnitus, vertigo, nausea and vomiting |
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Conductive hearing loss |
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caused by an impairment of the eardrum or bones in the middle ear |
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Sensorineural hearing loss (nerve deafness) |
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results from impairment of the cochlea or auditory nerve |
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Impacted cerumen |
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atypical accumulation of cerumen in the canal of the outer ear. (ear-wax buildup) |
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Infective otitis externa |
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inflammation of the external ear canal |
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Infective otitis externa HOW DIAGNOSED |
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an otologic examination and a symptoms confirm the diagnosis |
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Swimmer's ear |
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inflammation and resulting infection of the outer ear canal after water has been entrapped during swimming |
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Swimmer's ear SYMPTOMS AND SIGNS |
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severe pain, red swollen ear canal, hearing loss, fever, pruritis |
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Otitis media |
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inflammation of the normally air filled ear with the accumulation of the fluid behind the tympanic membrane (eardrum). occurring either unilaterally or bilaterally |
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Otitis media SYMPTOMS AND SIGNS |
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With serious Otitis media, the only symptoms may be a feeling of fullness or pressure and some degree of impaired hearing. Suppurative Otitis media is painful. General symptoms of infection, fever, chills, nausea and vomiting. Children often rub or pull at the affected ear and lean the head sideways toward the affected side. Dizziness, muffled hearing or loss of hearing. |
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Otitis media ETIOLOGY |
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can be acute or chronic. with acute, the cause is usually a virus from a URI that has spread through the eustachian tube into the middle ear. Chronic can develop from an acute attack, hypertrophy of the adenoids, or chronic sinus infections. Often follows a bout of influenza or mumps |
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Otitis media HOW DIAGNOSED |
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Otoscopy |
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Otitis media TREATMENT |
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Myringotomy (surgical evaluation of the fluid) |
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Meniere's Disease |
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a chronic disease of the inner ear that affects the labyrinth |
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Meniere's disease AGE AFFECTED |
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between 40 and 50 |
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Benigh Paroxysmal Positional Vertigo |
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usually a vestibilar system disorder |
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Benigh Paroxysmal Positional Vertigo SYMPTOMS AND SIGNS |
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a spinning sensation with moving of head, nausea, vomiting, involuntary eye movement, dizziness |
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Labrythitis |
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an inflammation or infection of the labyrinth of the inner ear |
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Labrythitis SYMPTOMS AND SIGNS |
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fever, extreme vertigo, nausea & vomiting |
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Labrythitis ETIOLOGY |
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usually the result of a virus but can be cause by a bacterial infection that has spread from the middle ear. May also be a result from meningitis |
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Ruptured Tympanic Membrane |
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any type of tear or injury to the eardrum |
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Ruptured Tympanic Membrane ETIOLOGY |
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insertion of sharp objects into ear canal, explosion, severe middle ear infection, a blow to the ear |
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Mastoiditis |
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inflammation of the mastoid bone, or mastoid process |
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Mastoiditis ETIOLOGY |
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Acute mastoiditis is the result of neglected acute otitis media. Chronic mastoiditis is associated with cholesteatoma |
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Sensorineual Hearing Loss (deafness) |
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sound waves reach the inner ear but are not perceived because the nerve impulses are not transmitted to the brain |
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Sensorineual Hearing Loss ETIOLOGY |
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nerve failure or damage to the cochlea or the auditory nerve. Aging process, loud noise, side affects of some medications like asprin |
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Sensorineual Hearing Loss PROGNOSIS |
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Sensorineual Hearing Loss that is caused by damage to the cochlea is IRREVERSIBLE. |
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Cancer of the ear |
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tumors of the ear can occur in any part of the ear and may be benign or malignant. They include cutaneous tumors of the external ear, ceruminal gland neoplasms, acoustic and facial neuromas, and glomus tumors. |
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