In human nervous system: Saccule and utricle Each saccule and utricle has a single cluster, or macula, of hair cells located in the vertical and horizontal planes, respectively. Resting upon the hair cells is a gelatinous membrane in which are embedded calcareous granules called otoliths. Changes in linear acceleration alter the… Read More
embryo development
In prenatal development: Ear …becomes chambers known as the utricle and saccule, related to the sense of balance. The dorsal part of the otocyst remodels drastically into three semicircular ducts, related to the sense of movement. Fibres of the acoustic nerve grow among specialized receptive cells differentiated in certain regions of these three divisions. Read More
equilibrium and sensory reception
In inner ear: Equilibrium The utricle and saccule each contain a macula, an organ consisting of a patch of hair cells covered by a gelatinous membrane containing particles of calcium carbonate, called otoliths. Motions of the head cause the otoliths to pull on the hair cells, stimulating another auditory nerve… Read More
In human sensory reception: Vestibular sense (equilibrium) …the vestibule (the saccule and utricle) react to steady (static) pressures (e.g., those of gravitational forces). Hair cells within these structures, similar to those of the semicircular canal, possess stereocilia and a kinocilium. They also are covered by a gelatinous cap in which are embedded small granular particles of calcium… Read More
In human ear: The physiology of balance: vestibular function … movements (angular acceleration); and the utricle and saccule within the vestibule, which respond to changes in the position of the head with respect to gravity (linear acceleration). The information these organs deliver is proprioceptive in character, dealing with events within the body itself, rather than exteroceptive, dealing with events outside… Read More
In human ear: Detection of linear acceleration: static equilibrium …are the maculae of the utricle and saccule. The left and right utricular maculae are in the same, approximately horizontal, plane and, because of this position, are more useful in providing information about the position of the head and its side-to-side tilts when a person is in an upright position.… Read More
influence on human visual system
In human eye: Reflex pathways …also do the gravity organ—the utricle—and the stretch receptors in the muscles of the neck. Thus, when the head is turned upward, there is a reflex tendency for the eyes to move downward even if the eyes are shut. The actual movement is probably initiated by the reflex from the… Read More
internal ear structure
In human ear: Vestibule …sacs of the vestibule, the utricle and the saccule, are known as the otolith organs. Because they respond to gravitational forces, they are also called gravity receptors. Each sac has on its inner surface a single patch of sensory cells called a macula, which is about 2 mm (0.08 inch)… Read More
perception of movement
In movement perception: Vestibular system …each inner ear, include the utricle, a small sac containing minute sensitive hairs associated with tiny sandlike granules called otoliths. The utricle functions as a linear accelerometer. When the head tilts relative to gravity or is accelerated, the relatively dense otoliths deflect the hair cells and nerve impulses are transmitted… Read More
