What are the Parts of the Hearing System?
The human hearing sense relies on a complex system that gathers sounds, amplifies them, and then sends signals to the brain which translates them into sensations we react to. Hearing is governed by the auditory system, which consists of both sensory organs and parts of the sensory system.
In simple terms, the parts that make up the sensory organ portion of the auditory system are divided into three regions — the outer ear, the middle ear, and the inner ear:
Outer ear: this is the visible part of the ear, made up of folds of cartilage that surround and include the ear canal. This outer part is called the pinna, and it is designed to both collect and amplify sounds. The outer ear also provides directional information to the brain; the way the sounds are reflected in one or both ears helps the hearer understand from which direction sounds are coming from.
Middle ear: this is the area where sounds begin the translation process. The inner edge of the air-filled ear canal marks the beginning of the middle ear. Here, the tympanic membrane, commonly called the eardrum, can be found. Connected to the tympanic membrane are three tiny bones that act as a sort of lever, translating the pressure waves of the sound into higher pressure vibrations that are sent to a smaller membrane called the vestibular window. The three bones of the middle ear are the:
- Malleus (hammer)
- Incus (anvil)
- Stapes (stirrup)
Inner ear: this part of the auditory system is where sound vibrations are converted to nerve impulses. The inner ear consists of the cochlea and several other structures. The cochlea looks somewhat like a snail shell and is filled with fluid. Inside this structure can be found three inner sections; two of them are separated by the basilar membrane. One of the sections is called the scala media, and inside it is a structure called the Organ of Corti. This structure is covered with tiny hairs that transform the waves of sound traveling through the fluid into electrical signals that are sent to the brain.