- Slides: 14
Hearing, Hearing Loss and the Human Ear • • • Hearing Test Hearing Frequencies Hearing Loss and Earbuds Teen Hearing Stats Hearing Loss Prevention The Human Ear • Outer, Middle and Inner Ear
1. Hearing Test (Pg 13) • Humans can generally hear from 20 Hz to 20, 000 Hz. • As we age we lose the ability to hear high frequencies. (Pg 13) • How old are your ears? (Pg 12)
Hearing Frequencies (pg 13) • Many animals can hear sounds a human cannot • For example “dog whistles” make a sound higher than humans can hear.
Hearing Loss and Earbuds (pg 13) • There are many ways to lose your hearing such as disease, trauma, aging, etc. , but the most common cause of hearing loss among teens is listening to music too loudly while wearing earbuds • Earbuds are especially bad since it sends the sounds directly into the ear
What causes hearing loss? (Pg 13) • Loud noises damage tiny nerves (called hair cells) found deep within the ear which prevents sound from reaching the brain • Loud noises (typically over 85 db which is about 50%-75% max volume on most devices) can permanently damage these hairs
Teen Hearing Stats (Pg 13) • 1/5 teens suffer from at least a slight hearing loss according to a recent article • 9/10 listen to music too loudly for too long • An i. Pod set at 50% volume is too loud and can lead to hearing loss What does hearing loss sound like?
Prevention (Pg 13) • Use headphones instead of earbuds to keep some of the direct sound out of your ears • Turn down the volume! • See a doctor if you experience any ringing in your ears • Stay away from speakers at concerts • Wear protection if you are constantly exposed to a loud environment (i. e. at work, etc. )
The Human Ear – The Anatomy of Hearing • The human ear consists of three basic parts: 1. The Outer Ear 2. The Middle Ear 3. The Inner Ear
The Outer Ear • Composed of the Pinna and Ear Canal • Is shaped to collect sounds • Notice how cupping your ear exaggerates its natural shape and increases its ability to hear
The Middle Ear • The eardrum (tympanic membrane) separates the outer and middle ear • The eardrum is less than 0. 1 mm thick • Sound causes the eardrum to vibrate
The Middle Ear Continued • There are three connected bones which attach to the eardrum • The Hammer (malleus), Anvil (incus) and the Stirrup (stapes) • These bones increase the sound and pass it on to the middle ear
The Middle Ear Continued • The middle ear is filled with air and is connected to the mouth • Pressure can buildup in the middle ear during altitude changes causing pain • Swallowing and yawning allows the air pressure to equalize causing your ears to “pop”
The Inner Ear • The inner ear contains a structure which resembles a snail shell called the cochlea which is filled with fluid • The movement of the last middle ear bone, creates waves in the cochlea’s liquid interior
The Inner Ear • The waves cause the movement of microscopic hairs inside the cochlea – Similar to grass moving in the wind • Their motion is changed into an electrical signal which is sent to the brain • The brain interprets these signals as sound