Functional morphology of the crista ampullaris: with special interests in sensory hairs and cupula: a review.

The functional significance of the ciliary interconnections and cupula has been reviewed. The ciliary interconnecting systems are divided into 2 types, i.e. side links and tip links. The side links acts to maintain the regular distance between the cilia thereby keeping the geometrical arrangement of the entire sensory hair bundle intact as well as to prevent close contact between neighbouring cilia. The tip links, stretching upwards from the tips of the shorter stereocilia to their taller neighbouring shafts, are actually involved in mechanoelectrical transduction. The cupula is composed of the cupula and subcupular meshwork. The subcupular meshwork consists of long branching filaments cross-bridged to one another. The cupula would function as a rigid plate and equally distribute the shear force of the cupula to all the ciliary bundles. The subcupular meshwork may play a role in the transmission of the shear strain force of the cupula to the ciliary bundle and may also exert an additional damping effect in order to prevent unwanted vibrations.