Mechanoreceptors in muscles, tendons, and walls of blood vessels that give information about the pressures acting on them are called Stretch sensors , Muscle spindles , and Golgi tendon organs . Mechanoreceptors that provide information for orientation and hearing are Hair cells . Hair cells have projections called stereocilia. When the stereocilia of some hair cells are bent in one direction, the receptor potential becomes more negative. When the stereocilia of some hair cells are bent in the opposite direction, it becomes more positive.
Sensory neurons send action potentials to the brain.
Hair cells that provide information about the movement of fish through the water are found in the fish s Lateral line . Hair cells that provide information for the gravitational orientation of invertebrates are found in the invertebrate s Statocysts . Hair cells that provide information for the gravitational orientation of vertebrates are found in the vertebrate s Semicircular canals and Vestibular apparatus . Hair cells that provide information for vertebrate hearing are found in the vertebrate s Organ of Corti . At the back of the eye is the retina which consists of several layers of neurons.