Book+3+2.4+How+You+Hear+Sound

IV. How You Hear Sound A. function of an ear is to gather sound waves and send, transmit information about sound to your brain B. 3 main sections - outer, middle, and inner ear C. Outer Ear 1. funnel sound waves- outermost part of ear 2. Ear canal - collects sound waves and directs then into a narrow region 3. Ear drum - small tightly stretched drum like membrane- vibrates D. Middle Ear- transmits the waves inward 1. contains 3 smallest bones in the body i. hammer- attached to ear drum- vibrates when eardrum does ii. anvil - receives vibration from the hammer iii. stirrup - receives vibrations form anvil E. Inner Ear - converts sound waves into a form that travels to your brain 1. cochlea - fluid filled cavity shaped like a snail shell 2. membrane separates stirrup and cochlea i. stirrup vibrates membrane which pass to a cochlea 3. vibrations move threw fluid, hair like cells moves causing messages to be sent to brain threw auditory nerve F. Hearing loss 1. many causes - aging, injury, infection, exposure to loud noises 2. can occur suddenly if eardrum is punctured or damaged 3. infection can damage inner ear 4. extended exposure to loud sounds i. damage hair cells 5. Aging i. hair cells in cochlea die and are not replace 6. Hearing aids can restore some hearing

__Quiz__ 1. ear canal - directs sound waves toward the eardrum 2. eardrum - sound waves make eardrum vibrate which causes the hammer to vibrate 3. cochlea - when a liquid inside cochlea moves it causes the tiny hair cells within it to move back and forth sending messages to brain 4. outer hair - collects sound waves and directs them toward the eardrum 5. middle ear - transmits vibrations from eardrum to the cochlea 6. inner ear - transforms vibrations caused by sound waves into messages that your brains processes 7. hearing loss - injury to eardrum; aging - hairs in cochlea die over time and are not replaces; exposure to loud noises over rime destroy hair cells; infection

__Study Guide__ 9. echolocation 14. eardrum 15. cochlea 23. Outer ear collects sound waves and directs them toward eardrum. Middle ear transmits vibrations caused by sound waves to cochlea. Inner ear turns waves into messages for brain. 26. hammer, anvil, stirrup 27. Hammer attached to eardrum, so when eardrum vibrates hammer does too. hammer transmits the vibrations to anvil, which causes stirrup to vibrate. 28. If bones damages, sound might not be transmitted threw middle ear. Cause hearing loss.