The sound waves coming from a sound producing body are collected by pinna of outer ear. these sound waves pass through the ear canal and fall on the eardrum. sound waves consist of compressions and rarefractions which makes the eardrum push inwards and outwards.this causes a small bone hammer to vibrate .then to  second bone anvil and stirrup. this vibrating stirrup strikes on the membrane of the oval window and passess the vibrations into the cochlea fluid and causes it to vibrate. this sets up electrical impulses and are carried by the auditory nerve to the brain. the brain interepts these and we get the sensation of hearing.
Theearis theorganofhearing, and in mammalsbalance. In mammals, the ear is usually described as having three parts—theouter ear,middle earand theinner ear. Theouter ear consists of thepinnaand theear canal, and as the outer ear is the only visible portion of the ear in most animals, the word "ear" often refers to the external part alone.[1]The middle ear includes thetympanic cavityand the threeossicles. Theinner ear sits in thebony labyrinth, and contains the semicircular canals, the utricle and saccule, and the cochlea. These facilitate a sense of balance and allow eye tracking when moving, allow a fixed sense of balance, and allow hearing, respectively. The ears ofvertebratesare placed somewhat symmetrically on either side of the head, an arrangement that aidssound localization.The ear develops from the firstpharyngeal pouchand six small swellings that develop in the earlyembryocalledotic placodes, which are derived fromectoderm.The ear may be affected by disease, including infection and traumatic damage. Diseases of the ear may lead tohearing loss,tinnitusandbalance disorderssuch asvertigo, although many of these conditions may also be affected by damage to the brain or neural pathways leading from the ear.