Basilar membrane - Wikipedia
Tectorial membrane: senses: Mechanical senses: a gelatinous membrane called entering the inner ear stimulates different regions of the basilar membrane. This downward deflection in turn causes the elastic basilar membrane to move If it were uniform, then the fluctuating pressure difference between the scala. There are three parts of the ear structure: the outer, middle and inner ear. The organ of corti is supported by a membrane called the basilar membrane. On top of these stereocilia is a jelly-like membrane called the tectorial membrane. . tallest ones have tip links leading to taller stereocilia beside them.
The inner ear contains the cochlea. This is the organ that converts sound waves into neural signals. These signals are passed to the brain via the auditory nerve. Coiling around the inside of the cochlea, the organ of Corti contains the cells responsible for hearing, the hair cells. There are two types of hair cells: These cells have stereocilia or "hairs" that stick out.
The bottom of these cells are attached to the basilar membrane, and the stereocilia are in contact with the tectorial membrane.
Cochlea and Vestibular System
Inside the cochlea, sound waves cause the basilar membrane to vibrate up and down. This creates a shearing force between the basilar membrane and the tectorial membrane, causing the hair cell stereocilia to bend back and forth. This leads to internal changes within the hair cells that creates electrical signals. Auditory nerve fibers rest below the hair cells and pass these signals on to the brain.
So, the bending of the stereocilia is how hair cells sense sounds. Outer hair cells have a special function within the cochlea. The sound energy entering via the oval window is all applied on one side of the basilar membrane.
Thus, sound entering the ear starts the basilar membrane vibrating.
Tectorial membrane - Wikipedia
But the basilar membrane is not uniform along its length, and different parts of the basilar membrane move the most in response to different frequencies of sound.
The portion of the basilar membrane near the oval window is more narrow and stiff. It thus moves preferentially with high frequencies.2-Minute Neuroscience: The Cochlea
At the other end, the basilar membrane is wider and more flexible. This end moves most in response to low frequencies. Thus, the basilar membrane is laid out like a piano keyboard, with different frequencies pitches moving different regions preferentially.
- Basilar membrane
The primary sensory cells in the cochlea are the hair cells. They lie along the basilar membrane.
Thus, when the basilar membrane moves up and down, the hair cells move up and down. The hair cells have projections at their top called stereocilia.
When the stereocilia are moved, mechanically gated ion channels open, the hair cells are depolarized and as a result glutamate is released as a neurotransmitter.
The glutamate then causes depolarization of the next neurons, which have axons that form the vestibulocochlear nerve.
The wavelength is long compared to the duct height near the base, in what is called the long-wave region, and short 0. Therefore, they are kept strictly separated. This separation is the main function of Reissner's membrane between scala vestibuli and scala mediaand it is also the function of tissue held by the basilar membrane such as the inner and outer sulcus cells shown in yellow and the reticular lamina of the organ of Corti shown in magenta.
For the organ of Corti the basilar membrane is permeable to perilymph. Here the border between endolymph and perilymph occurs at the reticular lamina, the endolymph side of the organ of Corti. There are approximately 15, hair cells in each human ear see figure. This function as base of the sensory cells gave the basilar membrane its name, and it is again present in all land vertebrates. Due to its location, the basilar membrane places the hair cells in a position where they are adjacent to both the endolymph and the perilymph, which is a precondition of hair cell function.