Chapter 6, Problem 77R

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 33.24 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 33.24 Effects of age aria occupational noise exposure. The graph shows the threshold hearing capacities fin decibels) for sounds of different frequencies (given in hertz) in a 25-year-okj carpenter (blue), a 50-year-old carpenter (red), and a 50-year-otd who did not have any on-the-job noise exposure (brown). 3. Which of the three people had the best hearing in the range of 4,000 to 6,000 hertz? Which had the worst?

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 33.24 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 33.24 Effects of age aria occupational noise exposure. The graph shows the threshold hearing capacities fin decibels) for sounds of different frequencies (given in hertz) in a 25-year-okj carpenter (blue), a 50-year-old carpenter (red), and a 50-year-otd who did not have any on-the-job noise exposure (brown). 4. Based on these data, would you conclude that the hearing decline in the 50-year-old carpenter was caused by age or by job-related noise exposure?

Figure 36.14 Cochlear implants can restore hearing in people who have a nonfunctional cochlea The implant consists of a microphone that picks up sound. A speech processor selects sounds in the range of human speech, and a transmitter converts these sounds to electrical impulses, which are then sent to the auditory nerve. Which of the following types of hearing loss would not be restored by a cochlear implant? Hearing loss resulting from absence or loss of hair cells in the organ of Corti. Hearing loss resulting from an abnormal auditory nerve. Hearing loss resulting from fracture of the cochlea. Hearing loss resulting from damage to bones of the middle ear.

The middle ear functions in__________. a. detecting shifts in body position b. transmitting sound waves c. sorting sound waves out by frequency d. all of the above

Label the parts of the eye:

Figure 14.9 The basilar membrane is the thin membrane that extends from the central core of the cochlea to the edge. What is anchored to this membrane so that they can be activated by movement of the fluids within the cochlea? Figure 14.9 Cochlea and Organ of Corti LM × 412. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)

Match each structure with its description. _____ cataract a. protects eyeball _____ cochlea b. transmits vibration to bone _____ eardrum c. functions in balance _____ lens d. detects pheromones _____ sclera e. interferes with vision _____ fovea f. contains chemoreceptors _____ taste bud g. focuses rays of light _____ Pacinian corpuscle h. has the most cones _____ pinna i. collects sound waves _____ vestibular apparatus j. sorts out sound waves _____ vomeronasal organ k. defects touch

The inner layer of the eye includes the _____________. a. lens and choroid b. sclera and cornea c. retina d. start of optic nerve

Which of the following are found both in the auditory system and the vestibular system? basilar membrane hair cells semicircular canals ossicles