Helton Hearing Care | 406-586-0914

Serving Montana With 3 Great Locations

(406) 586-0914

“ Our mission is to enhance the quality of life and sense of well-being of our valued clients and their families by providing exceptional, reliable and ethical hearing healthcare while exceeding the client's expectations of satisfaction at every level.”

How Hearing Works

How Hearing Works

Normal Ear Function

  1. Sound is transmitted through the air as sound waves from the environment. The sound waves are gathered by the outer ear and sent down the ear canal to the eardrum.
  2. The sound waves cause the eardrum to vibrate, which sets the three tiny bones in the middle ear into motion.
  3. The motion of the three bones causes the fluid in the inner ear, or cochlea, to move.
  4. The movement of the fluid in the inner ear causes the hair cells in the cochlea to bend. The hair cells change the movement into electrical impulses.
  5. These electrical impulses are transmitted to the hearing (auditory) nerve and up to the brain, where they are interpreted as sound.

The Outer Ear

The part of the outer ear that we see is called the pinna, or auricle. The pinna, with its grooves and ridges, provides a natural volume boost for sounds in the 2000 to 3000 Hz frequency range, where we perceive many consonant sounds of speech.

The ear canal, also called the external auditory meatus, is the other important outer ear landmark. The ear canal is lined with only a few layers of skin and fine hair, and is a highly vascularized area. This means that there is an abundant flow of blood to the ear canal. Wax (cerumen) accumulates in the ear canal and serves as a protective barrier to the skin from bacteria and moisture. Ear wax is normal, unless it completely blocks the ear canal.

The Middle Ear

The eardrum, or tympanic membrane (TM), is the dividing structure between the outer and middle ear. Although it is an extremely thin membrane, the eardrum is made up of three layers to increase its strength.

The ossicles are the three tiny bones of the middle ear located directly behind the tympanic membrane. These three bones form a connected chain in the middle ear. One of the bones is embedded in the innermost layer of the tympanic membrane, and the third bone is connected to a membranous window of the inner ear. The ossicles take mechanical vibrations received at the tympanic membrane into the inner ear.

The Eustachian tube is the middle ear's air pressure equalizing system. The middle ear is encased in bone and does not associate with outside air except through the Eustachian tube. This tubular structure is normally closed, but it can be involuntarily opened by swallowing, yawning, or chewing. It can also be intentionally opened to equalize pressure in the ears, such as when flying in an airplane. When this happens, you might hear a soft popping sound.

The Inner Ear

The inner ear is an organ located deep within the temporal bone, which is the bone of the skull on both sides of the head above the outer ear. The inner ear has two main structures: the semicircular canals and the cochlea.

  • Semicircular canals - These structures do not contribute to hearing, but assist in maintaining balance as we move.
  • Cochlea - This is the hearing organ of the inner ear, which is a fluid-filled structure that looks like a snail. The cochlea changes the mechanical vibrations from the tympanic membrane and the ossicles into a sequence of electrical impulses. Sensory cells, called hair cells, bend in the cochlea as the fluid is disrupted by the mechanical vibrations. This bending of the hair cells causes electrical signals to be sent to the brain by way of the auditory nerve. The cochlea is arranged by frequency, much like a piano, and encodes sounds from 20Hz (low pitch) to 20,000Hz (high pitch) in humans.

How You Hear

Hearing begins when the outer ear, the visible portion of the ear that is on the outside of the head, channels sound waves down the auditory canal. This tube-like passageway is lined with tiny hairs and small glands that produce ear wax.

The middle ear lies at the end of the auditory canal. It is composed of the eardrum and three small bones, known by the layman as the hammer, the anvil and the stirrup. When sound waves hit the eardrum, it vibrates and, in turn, moves the hammer. The hammer moves the anvil, which moves the stirrup, transmitting the vibrations into the inner ear. The middle ear functions to amplify sound, which is why significant hearing loss can result from any disruption in any of the parts.
The inner ear consists of the cochlea and the nerve of hearing. It converts sound waves into nerve impulses that travel to the brain via the movement of tiny hair cells. The brain, in turn, allows us to hear…as long as the message it is receiving is not distorted due to problems in the process just described.

Want to learn more?

Click here to learn about the types and causes of hearing loss.
Click here to learn what happens during a hearing test appointment.