The ear has two major functions:
Hearing: Detection of vibrations, their frequency (pitch) and amplitude (loudness).
Balance: Detection of direction of motion, acceleration and head position related to gravity.
       
Pinna: Said to collect sound waves and channel them into the external auditory canal.
External Auditory Canal: Earwax and hairs prevent foreign material entering the ear.
Eardrum (tympanum): Vibrates with the same frequency as the sound waves beating against it.
Ear Ossicles (hammer, anvil, stirrup): Transmit and amplify the vibrations of the eardrum to the inner ear.
Eustachian Tube: When it opens it equalises the air pressure on both sides of the eardrum allowing the eardrum to vibrate freely so accurate sound sensations are generated.
Oval Window: A flexible partition allowing transfer of vibrations to inner ear.
Round Window: A flexible partition to deaden the pressure changes in the inner ear.
Cochlea: Conversion of sound waves into nerve impulses, ‘hearing’ apparatus.
Auditory Nerve: Carries impulses from the cochlea to the brain’s hearing centre.
Semicircular Canals: Detection of direction of motion and acceleration — balance.
Utricle and Saccule: Detection of acceleration and head position related to gravity (balance).
Vestibular Nerve: Carries impulses from the balance organs to the cerebellum.