http://www.ck12.org Chapter 1. Human Biology
FIGURE 1.91
Sound waves travel through the air in all
directions away from a sound, like waves
traveling through water away from where
a pebble was dropped.FIGURE 1.92
Read the names of the parts of the ear in
the text; then find each of the parts in the
diagram.- At the end of the ear canal, the sound waves hit theeardrum. This is a thin membrane that vibrates like the
head of a drum when sound waves hit it. - The vibrations pass from the eardrum to thehammer. This is the first of three tiny bones that pass vibrations
through the ear. - The hammer passes the vibrations to theanvil, the second tiny bone that passes vibrations through the ear.
- The anvil passes the vibrations to thestirrup, the third tiny bone that passes vibrations through the ear.
- From the stirrup, the vibrations pass to theoval window. This is another membrane like the eardrum.
- The oval window passes the vibrations to thecochlea. The cochlea is filled with liquid that moves when the
vibrations pass through, like the waves in water when you drop a pebble into a pond. Tiny hair cells line the
cochlea and bend when the liquid moves. When the hair cells bend, they release neurotransmitters. - The neurotransmitters trigger nerve impulses that travel to the brain through the auditory nerve. The brain
reads the sound and “tells” you what you are hearing.