[Campbell Biology P.1164] According to Figure 50.13, which describes the organs of equilibriu... | Practice Question

According to Figure 50.13, which describes the organs of equilibrium, what is the sequence of events that allows the semicircular canals to detect angular movements of the head?

  • A: The cupula moves directly to stimulate hair cells, which then generate action potentials proportional to rotational acceleration.
  • B: Otoliths within the semicircular canals shift position, bending the hairs and increasing action potentials in afferent neurons.
  • C: The endolymph fluid within the semicircular canals flows, pressing against the gelatinous cupula and bending the hair cells embedded within it.
  • D: Pressure waves in the perilymph vibrate the basilar membrane, which then stimulates hair cells in the cupula.

Explanation

Figure 50.13 and its accompanying text explain that when the head starts or stops rotating, the fluid endolymph in the semicircular canals presses against the cupula a gelatinous cap , which in turn bends the hair cells embedded within it. This bending of hairs leads to an increase in the frequency of action potentials in afferent neurons, signaling rotational acceleration to the brain.