The cochlea of the inner ear contains hair cells, sensory receptors that transduce sound waves into neural signals that can be interpreted by the brain. Each sell has hair like stereocilia on top, arranged from shortest to tallest and attached to each other through thin tip links. Sound waves vibrate the basilar membrane beneath the hair cells, causing the cilia to move from side to side. When the cilia move towards the tallest cilium, the tip lengths stretch and pull open attached cat ion channels. Potassium ions flow into the cell, depolarizing it, making it more positively charged inside. The increase in voltage causes voltage-gated calcium channels to open and the resulting influx of calcium ions triggers the release of neurotransmitters onto the post-synaptic auditory nerve that carries information to the brain. When the cilia move toward the shortest cilium, the tip lengths are compressed and the cation channels close hyperpolarizing the cell, making it more negative inside, decreasing neurotransmitter release. In this way, hair cells are able to encode the characteristics of sound waves, such as frequency, into neural signals, allowing for perception.