In human hearing, the auditory receptors are and there are approximately in each ear.

In human hearing, the auditory receptors are hair cells, and there are approximately 15,000 in each ear.  Hair cells are the sensory receptors of both the auditory system and the vestibular system in the ears of all vertebrates.  They change the vibrations into electrical signals that are sent to the brain through the hearing nerve.

This type of galaxy is an approximately ellipsoidal shape and a smooth, nearly featureless image. they are the largest single star systems, in the universe and are built by the collisions of many smaller galaxies.