Left and right semicircular canal pairs respond to which type of motion?

Left and right semicircular canal pairs respond to which type of motion?

• A. Specific angular motion
• B. Linear acceleration
• C. Gravity
• D. Endolymph composition

Answer: (A)

Rotational (angular) movement of the head is what the semicircular canals detect. Each canal is oriented in a different plane, and when you start or stop turning, the endolymph inside the canal lags and pushes on the cupula in the ampulla. This deflects the hair cell stereocilia, changing the firing rate of the vestibular nerve. The brain uses these signals to sense angular velocity and acceleration and to coordinate eye movements via the vestibulo-ocular reflex. The left and right canal pairs provide direction information: turning in one direction increases activity on the corresponding canal while decreasing activity on the opposite canal. Linear acceleration and gravity are detected by the otolith organs (not the semicircular canals), and the composition of endolymph isn’t what drives the canal response.

Rotational (angular) movement of the head is what the semicircular canals detect. Each canal is oriented in a different plane, and when you start or stop turning, the endolymph inside the canal lags and pushes on the cupula in the ampulla. This deflects the hair cell stereocilia, changing the firing rate of the vestibular nerve. The brain uses these signals to sense angular velocity and acceleration and to coordinate eye movements via the vestibulo-ocular reflex. The left and right canal pairs provide direction information: turning in one direction increases activity on the corresponding canal while decreasing activity on the opposite canal. Linear acceleration and gravity are detected by the otolith organs (not the semicircular canals), and the composition of endolymph isn’t what drives the canal response.