Ear Anatomy and Function Quiz

Ear Anatomy and Function

• The ear has two main functions: hearing and balance.
• The ear is divided into three areas: outer ear, middle ear, and inner ear.
• Effective functioning of these areas is crucial for normal hearing.
• The auditory nervous system must be intact for sound to be transferred and interpreted.

Outer Ear: Structures and Functions

• Auricle (pinna): The visible part of the ear, acts as a funnel to direct sound into the ear; helps localize sound.
• Conchae: Resonating cavity within the pinna.
• Ear canal (external auditory meatus): A passage from the concha to the eardrum, transmits sound from the pinna to the eardrum; 1/3 cartilaginous, 2/3 bony meatus & resonates sound
• Tympanic membrane (eardrum): Thin, elastic, cone-shaped membrane at the end of the auditory canal, vibrates in response to sound waves, and is easily damaged.

Middle Ear: Structures and Functions

• Air-filled cavity: Between the eardrum and oval window.
• Ossicular chain: Malleus (hammer), Incus (anvil), Stapes (stirrup). Transmits sound efficiently and amplifies sound before transmitting it to the inner ear.
• Eustachian tube: Connects the middle ear to the nasopharynx and maintains equal air pressure and allows germs to spread.
• Oval and round windows: Two openings to the cochlea in the inner ear. The footplate of the stapes is embedded in the oval window, and the round window is sealed by the secondary TM.

Inner Ear

• Houses sensors: for balance (vestibular system) and hearing (cochlea).
• Inner ear receives: mechanical vibrations of sound through the movement of the stapes in the oval window.
• Semicircular canals: Part of the vestibular system, provide a sense of balance and information about the body's position and are responsible for equilibrium. Three fluid-filled tubes containing hair cells that detect movement in the fluid and send impulses to the brain.
• Cochlea: A small fluid-filled spiral in the temporal bone, receives sound waves from the oval window; sound waves are transmitted through the fluid to the cochlea. The basilar membrane is within the cochlea and contains thousands of cilia, which respond to sound, transducing movement into electrical signals, allowing vibration to be converted into electrical impulses along the auditory nerve. Different frequencies cause different areas of the basilar membrane to vibrate, creating different electrical signals.
• Organ of Corti: Contains inner and outer hair cells that turn vibrations into electrical impulses in the auditory nerve. Electrical signals travel to the brain for sound processing.

Clinical Note

• Hearing impairment: Damage to one or more parts of the ear, most common cause in children is otitis media (middle ear infection), can be caused by malformations, noise exposure, medications, wax build-up and nerve issues.
• Vertigo: Feeling of dizziness or whirling in space.
• Tinnitus: Ringing sound in the ears.

Additional Information

• There is a video on the physiology of hearing.
• A quiz is available to review knowledge.

Test your knowledge on the anatomy and functions of the ear with this quiz. Explore the outer, middle, and inner ear structures and their roles in hearing and balance. Ensure you understand the importance of each part for effective auditory processing.