Explain the structure of the middle and internal ear with the help of a diagram.

(N/A) The ear is divided into three parts: the outer ear,the middle ear,and the inner ear.
$1$. Middle Ear: The middle ear contains three ossicles called malleus,incus,and stapes (collectively known as ear ossicles). These are attached to one another in a chain-like fashion. The malleus is attached to the tympanic membrane and the stapes is attached to the oval window of the cochlea. The ear ossicles increase the efficiency of transmission of sound waves to the inner ear. An Eustachian tube connects the middle ear cavity with the pharynx,which helps in equalizing the pressures on either side of the ear drum.
$2$. Internal Ear: The fluid-filled inner ear is called the labyrinth,which consists of two parts: the bony labyrinth and the membranous labyrinth. The bony labyrinth is a series of channels. Inside these channels lies the membranous labyrinth,which is surrounded by a fluid called perilymph and filled with a fluid called endolymph. The coiled portion of the labyrinth is called the cochlea. The membranes constituting the cochlea,the Reissner's and basilar,divide the surrounding perilymph-filled bony labyrinth into an upper scala vestibuli and a lower scala tympani. The space within the cochlea called scala media is filled with endolymph. At the base of the cochlea,the scala vestibuli ends at the oval window,while the scala tympani terminates at the round window which opens to the middle ear.