Final answer:
The cochlea separates frequencies along its length through a process called tonotopic organization, relying on the varied mechanical properties of the basilar membrane and the corresponding activation of hair cells that allow humans to distinguish sounds within the range of 20 to 20,000 Hz.
Step-by-step explanation:
The way the cochlea separates frequencies along its length is often referred to as the tonotopic organization of the cochlea. The basilar membrane of the cochlea has mechanical properties that change along its length, which allows it to vibrate at specific locations depending on the frequency of the incoming sound waves. High frequency sounds cause vibrations near the base of the cochlea, while low frequency sounds affect the apex, leading to the activation of different hair cells that are sensitive to these specific frequencies.
The process relies on the structures within the cochlea, including the organs of Corti, scala vestibuli, and scala tympani. Fluid waves within the cochlea stimulate the basilar membrane, and the tectorial membrane also plays a role by moving only where the basilar membrane moves. This complex mechanism allows our brains to distinguish sounds ranging from 20 to 20,000 Hz, which corresponds to the range of human hearing.