Sound is collected by pinna/auricle (the visible part of ear), directed through outer ear canal(tube). Sound makes eardrum/tympanic membrane, which is a thin membrane, vibrate, which in turn vibrates 3tiny bones in middle ear. They r hammer/malleus, anvil/incus, u shaped stapes. Cochlea in inner ear is snail-shaped. 3loops of fluid filled tubes called semi circular canals attached to cochlea hep us maintain our sense of balance. Nerves carry electro chemical signals from cochlea to brain. Middle ear is connected to back of nose. It equalises pressure betn middle ear & air outside. when u “pop” ur ears as u change altitude, u’re equalising the air pressure in ur middle ear. On average, people can hear sounds in the freq’s betn 20-20,000Hz.