The Ear Anatomy Quiz

The Outer Ear

• The visible part of the ear is called the pinna or auricle
• The pinna is made of cartilage
• The outer ear is responsible for transmitting sound
• It is made up 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 2.5 cm long
• The skin surrounding the ear canal contains glands that secrete ear wax
• Ear wax is part of the ear's protection mechanism

The Middle Ear

• The middle ear is a small, air-filled space connecting the outer and inner ear
• It is responsible for conducting sound waves through the tympanic membrane to the cochlea via the ear bones
• The smallest bones in the body are in the middle ear, called the hammer (malleus), anvil (incus), and stirrup (stapes)
• These bones are collectively known as the ossicles
• Sound waves cause the ossicles to vibrate
• The eustachian tube connects the middle ear to the back of the throat
• It controls the pressure within the ear

The Inner Ear

• The inner ear has two main functions: converting sound waves into electrical signals for the brain and maintaining balance by detecting position and motion
• It consists of three main parts: the cochlea, the semi-circular canals, and the vestibule
• The cochlea is filled with liquid and acts like a microphone, converting sound waves into nerve impulses that travel to the brain via the auditory nerve
• The vestibule and semi-circular canals help with balance

How Do We Hear?

• Sound waves are funneled into the ear canal by the pinna
• The sound waves make the eardrum vibrate
• The vibrations cause the three ossicles to move
• The stapes vibrates, creating wave-like movements in the fluid inside the cochlea
• These movements stimulate hair cells inside the cochlea
• The hair cells generate nerve impulses, transmitted to the auditory nerve
• The nerve impulses travel to the auditory cortex in the brain
• The auditory cortex converts the nerve impulses into the sound we hear