They are covered with eyelashes (microscopic hair) and filled with a liquid substance known as endolymph. Each time the head moves, the endolymph moves the cilia. This works as a kind of motion sensor because the movements of the cilia are transmitted to the brain. As a result, the brain knows how to maintain body balance, regardless of posture. Read more on semicircular canals functions.
Semicircular canals functions
The semicircular canals of each ear contain three main parts: front, rear and horizontal. Each of these channels provides a separate sense of directional balance, and each channel on the left is always paired with the channel on the right for the normal function.
The front canal detects head movements back and forth, e.g. nodding. The back channel detects the inclination of the head as tilting the head towards the shoulders. The horizontal channel detects horizontal head movement, e.g. Rotation of the head to the side.
In semicircular canals functions, semicircular canals can be twofold. If any of the three separate pairs do not work, the person may lose their sense of balance. Hearing loss can also result from damage to these semicircular canals.
Each semicircular channel contains an ampoule or bulge that contains a receptor structure called crista ampullaris.
In another semicircular canals functions, Crista ampullaris reacts to rotational movements. The hair cells embedded in a gel-like mass in the shape of a cone called cupula.
When the liquid in the hemispherical channels rotates during movement, it displaces the cup that stimulates the hair cells.
Our sense of balance is based on the sensual structures of the inner ear, as well as on the visual inputs and information received from receptors in the body, especially those around the joints.
As mentioned, each of the three channels connects to the main structure of the vestibule. Now, if you think of a ring that someone could wear, you can imagine that the designer has created a metal loop, bonding both ends of the metal, right? In semi-circular canals, this connection creates a tubular chamber called an ampule (where both ends of the same channel meet, forming a loop). Inside the bulb, there is a jelly-known as cupula. Why cupula is gelatinous, you ask? Well, in the channel of hemispherical channels there is one more important component, it’s endolymph, which is essentially a fluid that flows down the sewers.