Light enters the eye through an opening called the pupil.

The light then passes through the lens, which focuses it on the retina at the back of the eye.

The retina contains light receptor cells. These cells send nerve impulses to the optic nerve.

Optic nerve carries the impulses to the brain.

The brain interprets the impulses and “tells” us what we are seeing. 

Sound waves enter the auditory canal and travel to the eardrum

Sound waves strike the eardrum and make it vibrate.

The vibrations then travel through several other structures inside the ear and reach the cochlea.

The liquid moves in response to the vibrations, causing tiny hair cells lining the cochlea to bend.

The hair cells send nerve impulses to the auditory nerve, which carries the impulses to the brain for interpretation.