Kuulmismembraan

Kuulmismembraan, also known as the basilar membrane, is a vibratory structure in the cochlea of the inner ear that separates two of the fluid-filled cavities: the cochlear duct and the scalatympani. It plays a crucial role in the process of hearing. The membrane is narrow and stiff at the base of the cochlea, near the oval window, and becomes wider and more flexible towards the apex.

When sound waves enter the ear, they cause vibrations that travel through the ossicles and into the oval window. These vibrations create pressure waves in the fluid within the cochlea. The basilar membrane vibrates in response to these pressure waves. The stiffness and width gradient of the membrane cause it to resonate differently at different frequencies. High-frequency sounds cause vibrations at the stiff, narrow base, while low-frequency sounds cause vibrations at the flexible, wide apex.

These vibrations of the basilar membrane move the organ of Corti, which rests upon it. The organ of Corti contains thousands of tiny hair cells, which are the sensory receptors for hearing. As the basilar membrane vibrates, the hair cells are bent against the tectorial membrane, another structure within the cochlea. This bending action triggers the release of neurotransmitters, which send electrical signals to the auditory nerve. The auditory nerve then transmits these signals to the brain, where they are interpreted as sound. Therefore, the basilar membrane acts as a frequency analyzer, separating complex sounds into their individual frequency components, which is fundamental to our ability to perceive different pitches.