1. in hearing, a patch of sensory tissue in the utricle and saccule of the inner ear that provides information about the position of the body in relation to gravity. The macula contains sensory hair cells whose processes (stereocilia) are embedded in a gelatinous matrix (cupula) containing calcareous particles (otoliths). When the orientation of the head changes, the relatively dense otoliths respond to gravity, causing the gelatinous mass to shift and the stereocilia to flex. This triggers nerve impulses in the hair-cell fibers, which act as signals to the brain.

2. in vision, see macula lutea.