The Human Ear

The Human Ear

• Composed of outer, middle and inner ear

The Outer Ear

• The visual part of the ear

• Composed of pinna and auditory canal

• The pinna acts as a funnel, collecting sound waves and directing them to the auditory canal

The Outer Ear

• The auditory canal transfers the waves to the middle ear

• Although humans can hear from 20 Hz to 20000 Hz, the auditory canal amplifies waves in the range of 1000 Hz to 5500 Hz

The Middle Ear

• The middle ear begins with the tympanic membrane

• Compressions push the tympanic membrane in, rarefactions pull it out

The Middle Ear

• The hammer, anvil and stirrup transfer the motion of the tympanic membrane to the inner ear, at the oval window

The Inner Ear

• The waves from the oval window cause waves in the cochlea, which is filled with fluid

• The waves travel through the cochlea, stimulating the microscopic hairs

The Inner Ear

• Each hair is attached to a nerve cell; when stimulated the wave is turned into electrical energy and that signal is sent to the brain this is what we “hear”

Why do my ears pop?

• The Eustachian tube is part of the middle ear and connects it to the mouth

• This tube opens when we swallow or yawn, equalizing the air pressure inside the middle ear

Why can an ear infection make me dizzy?

• The semicircular canals are located in the inner ear

• These canals are filled with fluid and are at approximately right angles to each other

• They transmit information to the brain about balance

How can someone pop their eardrum?

• This is called a perforated or ruptured eardrum

• Often the result of an ear infection – fluid builds up and causes a tear in the tympanic membrane

• The person feels a sharp pain and fluid drains from the ear

• The hearing loss is usually temporary, as the membrane often heals itself

How can someone pop their eardrum?

• You can also perforate / rupture your eardrum by poking it, sudden extreme air pressure changes, very loud noises, head injuries

What is earwax for?

• Earwax is made in the auditory canal

• The skin cells there have glands to produce earwax

• It’s called cerumen

What is earwax for?

• Earwax has several jobs:

1. Protects and moisturizes the skin in the ear canal

2. Fight infections

3. Shields the eardrum from the outside world

The Human Ear

• Human Ear Dissection