Ch 17 CCs
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Created by:
absolutesilence on January 19, 2011
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22 terms
Terms | Definitions |
|---|---|
 Hyposmia | a reduced ability to smell; often affects older people; can also be caused by neurological changes, such as a head injury, AD, Parkinson's, certain drugs and smoking |
| Taste aversion | people and animals quickly learn to avoid a food if it upsets the digestive system; drugs and radiation used to combat cancer often cause nausea and gastrointestinal upset regardless of what foods are consumed; cancer patients may lose their appetite because they develop taste aversions for most foods |
| Detached Retina | May occur due to trauma, in various eye disorders, or as a result of age-related degeneration; results in distorted vision and blindness in the corresponding field of vision; retina may be reattached by laser surgery or cryosurgery |
| Age-Related Macular Disease | degenerative disorder of the retina in people over 50; victims of advanced AMD retain their peripheral vision but lose the ability to see straight ahead; the leading cause of blindness in those over 75; initially may experience blurring and distortion at the center of the visual field |
| Dry AMD | central vision gradually diminishes because the pigmented layer atrophies and degenerates; no effective treatment |
| Wet AMD | 10% of cases of dry AMD progress to wet AMD; new blood vessels form in the choroid and leak plasma or blood under the retina; vision loss can be slowed by using laser surgery to destroy the leaking blood vessels |
| Presbyopia | As we age, the lens lose elasticity;by age 40, the near point of vision may have increased to 20 cm; by 60, 80 cm; usually begins in mid-40s; people begin to need glasses for reading; those with glasses start to need bifocals |
| LASIK | Most common type of refractive surgery to correct the curvature of the cornea for conditions such as farsightedness, nearsightedness, and astigmatism; the underlying layer of cornea is reshaped with a laser, one microscopic layer at a time |
| Color blindness | an inherited inability to distinguish between certain colors, result from the absence or deficiency of one of the three types of cones |
| Red-green color blindness | most common type of color blindness; red cones or green cones are missing; as a result the person cannot distinguish between red and green |
| Nyctalopia | night blindness; an inability to see well at low lights levels; may be caused by prolonged Vit A deficiency and the resulting below-normal amount of rhodopsin |
| Loud Sounds and Hair Cell Damage | continued exposure to high-intensity sounds is one cause of deafness (a significant or total hearing loss); the louder the sounds, the more rapid is the hearing loss; deafness usually begins with loss of sensitivity for high-pitched sounds; wearing earplugs with a noise-reduction rating of 30 dB while engaging in noisy activities can protect the sensitivity of your ears |
| Cochlear Implants | device that translates sounds into electrical signals that can be interpreted by the brain; useful for people with deafness that is caused by damage to hair cells in the cochlea |
| Cataracts | loss of transparency of the lens; the lens becomes cloudy (less transparent) due to changes in the structure of the lens proteins; often occur with aging; may also be caused by injury, excessive exposure to UV rays, certain medications (long term use of steroids), or complications of other diseases (diabetes); people who smoke also have increased risk; sight can be restored by surgical removal of the old lens and implantation of a new artificial one |
| Glaucoma | most common cause of blindness in the US; abnormally high intraocular pressure due to a buildup of aqueous humor within the anterior cavity; the fluid compresses the lens into the vitreous body and puts pressure on the neurons of the retina, damage to the optic nerve, and blindness; glaucoma occurs more often with advancing age; risk factors- race (AA are more susceptible), increasing age, family history and past eye injuries and disorders |
| Deafness | significant or total hearing loss |
| Sensorineural deafness | caused by either impairment of hair cells in the cochlea or damage of the cochlear branch of the vestibulocochlear (VIII) nerve; may be caused by atherosclerosis, which reduces blood supply to the ears; by repeated exposure to loud noise, which destroys hair cells of the spinal organ; and/or by certain drugs such as aspirin and streptomycin |
| Conduction deafness | cause by impairment of the external and middle ear mechanisms for transmitting sounds to the cochlea; causes- otosclerosis, the deposition of new bone around the oval window; impacted cerumen; injury to the eardrum; and aging which often results in thickening of the eardrum and stiffening of the joints of the auditory ossicles |
| Weber's test | hearing test used to distinguish between sensorineural and conduction deafness; the stem of a vibrating fork is held to the forehead; in people with normal hearing, the sound is heard equally in both ears; if heard best in the affected ear, its probably conduction; if heard best in the normal ear, it is probably sensorineural |
| Ménière's Disease | results from an increased amount of endolymph that enlarges the membranous labyrinth; symptoms- fluctuating hearing loss and roaring tinnitus (ringing); spinning or whirling vertigo (dizziness) is characteristic of MD; almost total destruction of hearing may occur over a period of years |
| Otitis Media | acute infection of the middle ear caused mainly by bacteria and associated with infections of the nose and throat; symptoms- pain, malaise, fever, and a reddening and outward bulging of the eardrum, which may rupture unless drained; bacteria passing into the auditory tube from the nasopharynx are the primary cause of middle ear infections; children are more susceptible |
| Tympanotomy | surgical procedure used if OM occurs frequently; consists of the insertion of a small tube into the eardrum to provide a pathway for the drainage of fluid from the middle ear |
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