The Structure & Function of the Human Ear PDF

THE Structure & The STRUCTURE Function of the & FUNCTION Human OF THE Ear HUMAN EAR  The Human Ear – The Outer Ear Outer Ear The visible part of the ear is called the Pinna or the Auricle. The pinna is made of cartilage. The outer ear is concerned with the transmis...

THE Structure & The STRUCTURE Function of the & FUNCTION Human OF THE Ear HUMAN EAR  The Human Ear – The Outer Ear Outer Ear The visible part of the ear is called the Pinna or the Auricle. The pinna is made of cartilage. The outer ear is concerned with the transmission of sound. The outer ear consists of the Pinna, the ear canal and the outer layer of the eardrum, also called the Tympanic membrane. The ear canal is filled with air and is about 2.5cm long. The skin surrounding the ear canal contains glands that secrete ear wax. Ear wax is part of the ears protection mechanism.  The Human Ear – The Middle Ear Middle Ear The middle ear is a small air filled space connecting the outer and inner ear. The Primary function of the middle ear is to conduct sound waves through the tympanic membrane to the cochlear via the ear bones. The 3 smallest bones in the body are in the middle ear, the are called the hammer (malleus), anvil (incus) and stirrup (stapes). These bones are collectively known as the ossicles. Sound waves cause them to vibrate. The eustachian tube is also inside the middle ear. The eustachian tube controls the pressure within the ear. Hammer Anvil Stirrup  The Human Ear – The Inner Ear Inner Ear The Inner Ear has 2 main functions, to convert sound waves into electrical signals for the brain and to maintain balance by detecting position and motion. The inner ear has 3 main parts, the cochlear, the semi-circular canals and the vestibule. The cochlear is filled with liquid and acts like a microphone, converting sound waves to nerve impulses that travel to your brain via the auditory nerve. The vestibule and semi-circular canals both help you to balance. Semi circular canals – aid with balance Cochlear – aid with hearing  Outer Ear Middle Ear Inner Ear Cartilage Cochlear Pinna Hammer (Malleus) Semi-circular canals Anvil Tympanic (Incus) Membrane Auditory Nerve Vestibule Ear Canal Ear Drum Stirrup Wax Glands (Stapes) Eustachian Tube  How Do We Hear? Sound waves are Vibrations of the ear funnelled into our The sound waves drum cause the 3 small ear canal by the make our ear bones in the ear, pinna. drum vibrate. collectively called the ossicles, to move. The hairs in the cochlear are These waves As the last bone in the tuned to respond stimulate chain, the stapes, to differences in microscopic hairs vibrates this causes sound frequency inside the wave like movements to and pitch. cochlear. be generated in the fluid inside the cochlear. When stimulated these hair cells generate nerve impulses that are transferred to the The nerve impulses The auditory auditory nerve. travel along the cortex converts auditory nerve into the nerve the hearing centre impulses into the of the brain, called sound that we the auditory cortex. hear.  Video Resources Cognito video Physics #73 from TedED Science of Hearing