How does semicircular canals function to dynamic equilibrium?

Answer 1

The inner ear includes the three semicircular canals. They (plus the base of each called the ampullaris) are involved in:

1. Static Equilibrium is in the ampulla which contains the sense for position of head when body is not moving. Static balance is associated with the vestibule and is involved in evaluating the position of the head relative to gravity. Tiny stones called otholiths on a membrane filled with hairs cause this sensation.

The system also responds to linear acceleration or deceleration, such as when a person is in a car that is increasing or decreasing speed.

2. Dynamic Equilibrium is in the semicircular canals which senses rotation and movement of head and body. Dynamic balance is associated with the semicircular canals and is involved in evaluating changes in the direction and rate of head movements and doesn't use gravity. The semicircular canals detect changes in the rate of movement rather than movement alone because displacement of the cupula is most intense when the rate of head movement changes rapidly.

As with the static balance, the information the brain obtains regarding dynamic balance is largely subconscious.

Answer 2

You have three semicircular canals in your internal ear. They are placed at right angle to each other. You go to the corner of your room. Here three surfaces meet each other. Each surface have one semicircular canal. They have to be only partially filled with the fluid. When you change the position of the head, the level of the fluid is horizontal, but vary in each canal. The signal is sent to the central nervous system and you come to know about the position of your head in the space.