Auricle / Ear

The rat’s ear is an organ of hearing and equilibrium. It is made up of the outer or external ear, the middle ear, and the inner ear.

The outer or external ear is composed of the concha auriclae (or pinna), seen as the large outer flap of the ear, and the auditory canal.

The middle ear is composed of the tympanic cavity (housing the ossicles: the malleus, the incus, and the stapes), the tympanic membrane (composed of squamous epithelium), and the nearly horizontal Eustachian tube.

The inner ear is composed of the labyrinth (concerned with equilibrium) and the cochlea (containing nerves that transmit sound to the brain).

Sebaceous glands called Zymbal’s Glands are found at the base of each ear and consist of stratified squamous epithelium. These glands open into the auditory canal of the external ear.

Degenerative changes that occur to the ear through aging, infection, or tumors can affect both the sense of balance and hearing.