Cochlea is the coiled part of the labyrinth. Cochlea is the auditory organ present in the inner ear. Auditory receptors are present in the cochlea. It converts the auditory signals to neural impulses, which are carried by the afferent nerves fibres and auditory nerves to the brain, where it is integrated and we hear the sound.
- Cochlea is the coiled part of the inner ear or labyrinth. It looks like a snail.
- The coiled membranes of the cochlea, reissner’s membrane and the basilar membrane separate the bony labyrinth filled with perilymph into three canals.
Scala vestibuli- upper
Scala media- middle
Scala tympani- lower
- The scala vestibuli and the scala tympani are filled with the perilymph and connect the upper part of the cochlea. The scala vestibuli opens at the oval window and the scala tympani opens into the middle ear through the round window.
- The middle scala media is filled with the endolymph and contains the auditory organ, i.e. the organ of Corti.
- The organ of Corti is composed of thousands of hair cells present on the basilar membrane. The apical part of each hair cell has a process known as stereocilia.
- Tectorial membrane is present above the line of hair cells.
- Hair cells are in close contact with the afferent neurons.
The auditory receptors are present in the cochlea. The pressure waves generated by the sound vibrations are transferred to the endolymph and this causes movement in the basilar membrane. The bending of the hair cells against the tectorial membrane results in the generation of nerve impulses in the afferent neuron present at the base in the close proximity of the hair cells. The action potential thus generated travels to the brain via auditory nerves. The brain integrates the electrical signal and we recognise the sound.
We are also able to recognise the pitch of the sound, it depends on the part of the basilar membrane, which gets stimulated. High frequencies are recognized by the cochlear hair cells present at the base and low frequencies by the hair cells present at the top.
The loudness is recognised by the number of impulses transmitted by the cochlear nerve. A loud sound having greater amplitude stimulates the hair cells more intensely.
So the cochlea is responsible for the hearing function of the ear.
This was in brief about the Cochlea Function. Get access to all the NEET Questions with explanations, only at BYJU’S.