Bell Work Wavelength is to ______________ as ___________ is to brightness hue, intensity intensity, hue frequency, amplitude brightness, hue amplitude, intensity

Announcements Tomorrow-SUMMATIVE :D Next Thursday-Guest Speaker Monday, November 24-States of Consciousness (Chapter 7)

Decibel Intensity hearing threshold breathing 10 whispering 25 breathing 10 whispering 25 normal conversation 60 screaming child 90 jackhammer 100 chain saw 110 amplified rock concert 90–130 shout into ear at 20 cm 120 car horn siren threshold of pain 120–140 gunshot 140 jet engine 12-gauge shotgun 165 rocket launching 180 loudest audible tone 194

Hearing Loss Hearing loss and deafness can result from sound exposure, heredity, ototoxic drugs (chemicals that damage auditory tissues), accidents, and disease or infection. Conductive hearing loss results from damage to the outer or middle ear, and sensorineural hearing loss results from damage to the inner ear. Damage associated with conductive hearing loss interferes with the efficient transfer of sound to the inner ear. Conductive hearing loss is characterized by a loss in sound intensity. Voices may sound muffled, while at the same time the individual’s own voice may seem quite loud. It can be caused by anything that interferes with the vibration of the eardrum or with the movement of the bones of the middle ear. Even a buildup of earwax can lead to conductive hearing loss. An ear doctor can simply remove a buildup of earwax. It should be pointed out, however, that you should never try to remove wax from your own ears. You can too easily push the wax further into the ear canal and even damage your eardrum. A common cause of conductive hearing loss in children is ear infections. Other causes of conductive hearing loss are a punctured eardrum or otosclerosis (a buildup of spongy tissue around the middle ear). These can be treated through surgery.

Hearing Loss Sensorineural hearing loss is generally associated with damage to the hair cells in the inner ear. When hair cells are damaged, their ability to participate in sound transduction is compromised. If your hair cells are completely destroyed, you will be unable to hear any sounds, no matter how loud they are. If the hair cells are damaged, you may still hear sounds, but the sounds will be distorted. Different hair cells respond to different pitches. Typically, hair cells that respond to higher pitches are lost first. One reason is that the basilar membrane vibrates more vigorously in response to higher pitches. These vibrations can cause the delicate stereocilia of the hair cells to be sheared off. One consequence of this damage is that it becomes more difficult to understand the higher-pitched voices of women and children. It also becomes more difficult to distinguish a person’s speaking voice from background noise. The effects of noise-induced hearing loss may be temporary or permanent, depending on the intensity and duration of the exposure. Although a person’s hearing may recover from temporary, slight damage to the hair cells, the complete loss of hair cells is irreversible in humans.

Hearing Loss The phrase “too loud, too long, too close” summarizes the causes of noise-induced hearing loss. The intensity, duration, and proximity of sound to the listener determine whether or not damage occurs and if that damage is reversible or permanent. Hearing loss can result from a single loud noise, such as an explosion, but more commonly results from repeated exposure to less intense sounds that are close by.