Hospital corpsmen were previously trained at Naval Hospital Corps School, Great Lakes, Illinois until the 2011 Base Realignment and Closure Bill caused Hospital Corps School to be relocated to the Medical Education and Training Campus (METC) at Joint Base San Antonio, Texas.
characteristic of highness or lowness of a sound is called The frequency of a sound wave determines the pitch of the sound you hear. Remember that frequency is the number of waves passing a fixed point in a given period of time. A high-frequency wave with short wave-lengths, such as that produced by a tiny flute, makes a high-pitched sound.
The amount of waves per unit time corresponds to a  certain frequency, so when you hear a low sound there are less  waves per second than when you hear a high pitched sound that has  lots of waves per second. The range of frequencies most humans can  hear is from 20 Hz (waves/second) to 20,000 Hz.     Sound Waves Cause The Eardrum to Vibrate,The Vibrations Travel  Through The Hammer, Anvil, And The The Stirrup To The Inner  Ear,Cells In The Cochlea Detect The Vibrations And Send The Message  To The Brain.