Cochlea the oval window) to the "apex" (the top or center of the spiral). The spiral canal of the cochlea is a section of the bony labyrinth of the inner ear that is approximately 30 mm long and makes 2¾ turns about the modiolus. The cochlear structures include: The cochlea is a portion of the inner ear that looks like a snail shell (cochlea is Greek for snail.) The cochlea receives sound in the form of vibrations, which cause the stereocilia to move. The stereocilia then convert these vibrations into nerve impulses which are taken up to the brain to be
Evolution of the cochlea at the same time as the water-to-land transition of vertebrates, approximately 380 million years ago. The actual coiling or spiral nature of the cochlea occurred to save space inside the skull. The longer the cochlea, the higher is the potential resolution of sound frequencies given the same hearing range. The oldest of the truly coiled mammalian cochleae were approximately 4 mm in length. The earliest evidence available for primates depicts a short cochlea with prominent laminae, suggesting that they had good high-frequency sensitivity as opposed to low-frequency sensitivity. After this, over a period of around 60 million years, evidence suggests