The human ear is an organ whose primary function is to hear a sound and to detect and analyze noise by transduction (sound waves are converted into the electrical impulses). In some mammals, it is also used for the sense of balance. Now the question is how compression in air results in sound in our brain.
The compression in the air has to be converted into electrical signals for our brain to detect. Let’s study the structure of the ear and how the whole process of conversion of air compression into electrical signals takes place.
Structure of Human Ear
There are three parts of ear – the outer ear, middle ear and the inner ear. The outer ear consists of pinna and ear canal. The middle ear consists of the eardrum and the three ossicles. The inner ear includes semicircular canals that are connected to cochlea and auditory system.
The compressions in the air reach the outer ear called pinna which directs the sound to travel through the ear canal to reach the ear drum or tympanic membrane. Due to these compressions, the membrane starts vibrating. This thin membrane vibrates and relaxes depending on the amplitude of compression in air. The vibration is then passed to three bones in the ear connected to the ear drum: hammer, anvil and stirrup and is amplified about 20 times than the actual vibration.
After the amplification by ear bones, this vibration is passed through the oval ear called cochlea. A liquid is present in the cochlea. When the vibrations are sent to this liquid, it creates waves and gets the electrical signal out of the cochlea. Now from cochlea it is sent to brain through the auditory nerve. Brain reads the electrical impulses and detects it as sound. We have an Eustachian tube at the bottom which connects the ear with the nasopharynx, a part of nose.