The Ear

Functions Detects sound Helps maintain balance Maintains alertness Aids emotion, memory, detection of body language and thought

Parts of the Ear There are 3 parts that make up the ear External Ear: Includes the auricle (pinna), the auditory canal and the eardrum. Middle Ear: Comprised of the 3 smallest bones in the human body. These are the malleus (hammer), the incus (anvil) and the stapes (stirrup). Inner Ear: Where the cochlea is located. The cochlea is filled with liquid that helps the body maintain its balance. The cochlea also has about 20,000 cells that transmit signals to the brain. These are called ciliated cells.

External Ear

Pinna: visible part of the ear

Ear Canal: Directs sound to middle ear

Ear Drum: receives sound and sends it to the malleus

Middle Ear

Malleus, Incus, Stapes: Transmit sound waves from the ear drum to the inner ear

Inner Ear

Cochlea The cochlea is a snail-shell shaped part of the ear divided into 3 different parts filled with fluid. Tympanic Canal (Perilymph fluid) Vestibular Canal (Perilymph fluid) Cochlear Duct (Endolymph fluid)

Cochlea These liquids move around in response to sound waves being received from the middle ear. As the perilymph moves, the cochlear partition moves. As the cochlear partition moves, thousands of ciliated cells sense the motion and turn it into electrical signals which are then sent to the brainstem.

Cochlea

Organ of Corti This is the part of the ear that is filled with 16,000-20,000 of hair cells. When these hairs are moved, they send messages to the brain.

Eustachian Tube Adjusts the air pressure in the ear drum and connects the ear to the nose.

Auditory Nerve Takes electrical impulses from the cochlea and makes connections with the auditory area of the brain.

How Can We Hear? Sound waves travel into the ear and reach the eardrum The eardrum passes the vibrations from the sound waves through the middle ear bones and into the inner ear When these vibrations reach the cochlea, the ciliated cells convert the vibrations into electrical signals Then, these signals are sent to the brain via the auditory nerve

What Causes Deafness? Head trauma Aging Hereditary hearing loss Disease Exposure to loud noises

Conductive Hearing Loss When hearing loss is because of problems with the external or middle ear. Causes include: allergies, impacted earwax, tumors, infection, fluid in the middle ear, malformation Can be treated with surgery

Sensorineural Hearing Loss When hearing loss is because of problems in the inner ear. Causes include: exposure to loud noise, head trauma, malformation, otosclerosis, Menieres disease Can be treated with surgery or therapy

Otosclerosis An abnormal bone growth in the middle ear that prevents vibrations to be passed on thought the ear.

Menieres Disease Inner ear disorder that causes hearing loss and episodes of vertigo Named after a French physician, Prosper Ménière, who first said that vertigo was caused by inner ear disorders Symptoms: pressure in ears, vertigo, migraine Causes: when fluid from the inner ear leaks and goes into other areas of the ear Treatments: surgery, physiotherapy

Earwax Medical Term: cerumen Assists in cleaning and lubrication and provides protection from bacteria, water, and fungi