Chapter 6, Problem 72R

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?

Label the parts of the eye:

Visit this site (http://openstaxcollege.org/l/NYTmeningitis) to read about a man who wakes with a headache and a loss of vision. His regular doctor sent him to an ophthalmologist to address the vision loss. The ophthalmologist recognizes a greater problem and immediately sends him to the emergency room. Once there, the patient undergoes a large battery of tests, but a definite cause cannot be found. A specialist recognizes the problem as meningitis, but the question is what caused it originally. How can that be cured? The loss of vision comes from swelling around the optic nerve, which probably presented as a bulge on the inside of the eye. Why is swelling related to meningitis going to push on the optic nerve?