Question

What part of the ear contains the sensory receptors for hearing?

Answer 1

Hint: Ear is the organ of hearing. Making balance is also an important function of the ear. The ear has three parts: - $1.$ External ear, $2.$ Middle ear and $3.$Internal ear. The sound transmission takes place in the external and the middle ear. The inner ear has Cochlea and the peripheral vestibular system.

Complete answer:
Hearing begins with the external ear. When a sound is made outside of the external ear, the vibrations or the sound waves go through the external auditory canal and strike the tympanic membrane or eardrum. Then the membrane vibrates. The vibrations are then passed to the three small bones of the middle ear. These small bones are called auditory ossicles. The sound waves are amplified by these three ossicles. These ossicles send the sound waves into the cochlea, the hearing organ of the internal ear.
When the sound waves reach the internal ear, they convert into electric impulses. The auditory nerve sends these impulses to our brain. Then our brain translates these electrical impulses as sound.
Our ear has its own protective mechanism against loud sounds. The muscles attached to the malleus and stapes reduce the vibrations and protect the cochlea from damage. This process is called acoustic reflex. The process takes $40$ milliseconds to occur. So, if there is a sudden loud sound like an explosion, then this mechanism doesn’t occur in time and it causes severe damage to the cochlea. It can result in the total loss of hearing.

Note:
The names of the three ossicles of our middle ear are Malleus, Incus and stapes. The stapes are the smallest bone of our body. In the foetus the auditory cortex is fully formed. Auditory cortex is the hearing part of our brain. That’s why the new born babies can hear properly.