Chapter 3, Problem B6CR

Occupational Hearing Loss Frequent exposure to loud noise of a particular pitch can cause loss of hair cells in the part of the cochlea that responds to that pitch. People who work with or around noisy machinery are at risk for such frequency-specific hearing loss. Taking precautions such as using ear plugs to reduce sound exposure is important. Noise-induced hearing loss can be prevented, but once it occurs it is irreversible because dead or damaged hair cells are not replaced. FIGURE 33.11 shows the threshold decibel levels at which sounds of different frequencies can be detected by an average 25-year-old carpenter, a 50-year-old carpenter, and a 50-year-old who has not been exposed to on-the-job noise. Sound frequencies are given in hertz (cycles per second). The more cycles per second, the higher the pitch. FIGURE 33.11 Effects of age and occupational noise exposure on hearing. The graph shows the threshold hearing capacities (in decibels) for sounds of different frequencies (given in hertz) in a 25-year-old carpenter (blue), a 50-year-old carpenter (red), and a 50-year-old who did not have any on-the-job noise exposure (brown). Which sound frequency was most easily detected by all three people?

Occupational Hearing Loss Frequent exposure to loud noise of a particular pitch can cause loss of hair cells in the part of the cochlea that responds to that pitch. People who work with or around noisy machinery are at risk for such frequency-specific hearing loss. Taking precautions such as using ear plugs to reduce sound exposure is important. Noise-induced hearing loss can be prevented, but once it occurs it is irreversible because dead or damaged hair cells are not replaced. FIGURE 33.11 shows the threshold decibel levels at which sounds of different frequencies can be detected by an average 25-year-old carpenter, a 50-year-old carpenter, and a 50-year-old who has not been exposed to on-the-job noise. Sound frequencies are given in hertz (cycles per second). The more cycles per second, the higher the pitch. FIGURE 33.11 Effects of age and occupational noise exposure on hearing. The graph shows the threshold hearing capacities (in decibels) for sounds of different frequencies (given in hertz) in a 25-year-old carpenter (blue), a 50-year-old carpenter (red), and a 50-year-old who did not have any on-the-job noise exposure (brown). How loud did a 1,000-hertz sound have to be for the 50-year-old carpenter to detect it?

Why do people over 55 often need reading glasses? Their cornea no longer focuses correctly Their lens no longer focuses correctly Their eyeball has elongated with age, causing images to focus in front of their retina Their retina has thinned with age, making vision more difficult.

Jill is diagnosed with sensorineural deafness, a disorder in which sound waves are transmitted normally to the inner ear but they are not translated into neural signals that travel to the brain. Sometimes the cause is a problem with the auditory nerve, but in Jills case it has to do with a problem in the inner ear itself. Where in the inner ear is the disruption most likely to be located?

Rods differ from cones in the following ways: a. They detect dim light, not bright light. b. They have a different visual pigment. c. They are not located in the retina. d. All of the above. e. a and b only

Your visual field is ______________. a. a specific, small area of the retina b. what you actually see c. the area where color vision occurs d. where the optic nerve starts