What is the Vestibular System?
The vestibular system is made of up three components – the central processing system (brain and brainstem), the peripheral vestibular apparatus (the inner ear and pathways to brainstem) and a system to generate motor output.
The vestibular system is also referred to as the inner ear because the peripheral vestibular apparatus resides in each ear and is connected to the cochlea which is part of the hearing mechanism.
Within the inner ear there are five organs that provide your brain with information about head movements and static postures of the head relative to gravity. How does this all work?
- There are Three Semicircular Canals which contain fluid (endolymphatic fluid) and specialized hair cells embedded in a gel-like substance (the cupula) that act as motion sensors. When you turn your head, the fluid flows to excites the hair cells and this detect angular accelerations of the head. These canals do not detect gravity
- There are Two Otolith Organs (Utricle and Saccule) that also contain fluid (endolymphatic fluid) and specialized hair cells embedded in a gel-like substance (the maculae) which also has calcium carbonate crystals or otoconia. These crystals give more mass to the receptors and causes the maculae to be sensitive to gravity. These organs detect tilts and translations of the head, because they respond primarily to linear acceleration forces like gravity.
Finally, the vestibular nerve is a part of the 8th cranial nerve and it provides innervation from the brain to the inner ear.
This is just a very brief overview of the components of our vestibular system. As you can see it is a complex system and when there is a problem in one or more of these components, the results can cause symptoms such as dizziness and vertigo, result in falls and affect many aspects of daily life. Keep following along for more information about balance, dizziness and common vestibular disorders.
If you are interested in booking a vestibular assessment with a registered physiotherapist with specialize training in vestibular disorders click here or call the clinic at 416-545-1881.