Ear Ringing and the Inner Ear

To understand tinnitus better, what causes it, and what can be done to stop ringing ears, it helps to know something about our hearing and how it works. This third article in a three part series introduces the basic anatomy of the inner ear, what it does, how it can go wrong to give rise to tinnitus, and how it can be treated. The other two articles focus on the outer ear and the middle ear and tinnitus. With no further ado, let's get a look at the inner ear.

Up to this point, we have traced the movement of sound waves through the air, then gathered by the pinna, funneled through the auditory canal, at the end of which the sound energy impacts the eardrum. The tympanic membrane then vibrates with the energy of that sound, and transmits it to the middle ear via the ossicles, those three tiny bones, the hammer, anvil, and stirrup, which amplify and focus the sound, leveraging the sound energy for when the stirrup or stapes strikes the cochlea, which takes us to the starting point of the inner ear.

The medium through which the sound has traveled up to this point has been air, which is much less dense than fluid, but within the inner ear the sound energy encounters the much denser medium of the fluid-filled cochlea. Overcoming the greater inertia or resistance of the denser fluid medium of the inner ear is the reason for the amplification of the sound energy performed by the ossicles of the middle ear. And inside the cochlea of the inner ear the sound energy continues on to the brain in a very different manner.

The cochlea has been so named because its shape resembles a snail or spiral shell, which "cochlea" literally means. It is inside the cochlea where the mechanical vibrations are transduced or converted to electrical nerve impulses which the brain then processes as hearing.

The cochlea essentially consists of three fluid filled tubes or canals. When the stapes of the middle ear presses its vibrations against the oval window of the cochlea, two of the canals, the vestibular and the tympanic canals, receive and transmit the energy onward. The organ of Corti, which is located in the third canal known as the cochlear canal, senses the pressure impulses and converts them into electrical impulses and sends them down the auditory nerve to the brain. These three canals, tubes, or ducts, are curved together into the snail shell shape, giving the cochlea its form. Separating these ducts is a thin membrane called the basilar membrane.

The basilar membrane serves as the base for the tiny hair cells, the 20,000 or so sensory receptor cells. These hair cells react with the various frequencies of the sound waves that are being transferred through the cochlea, creating tiny electrical impulses. Then, the organ of Corti which is situated on the basilar membrane, serving a microphone like function, sends those electrical impulses down the auditory nerve to the brain to be processed as recognizable sounds.

If the inner ear did nothing else but carry out its roll in hearing, we could be amazed enough, but the inner ear also functions to keep the head and body in balance. Certain other functions of the body also contribute to balance, such as the sense of sight and input from muscles, but the vestibular system of the inner ear is the centerpiece for maintaining balance.

The vestibular system has three essential parts: the utricle, the saccule, and the 3 semi-circular canals or ducts. The utricle and saccule determine the position of the head at all times. That function is important for keeping the head in line with the body. The utricle and saccule are both sensitive to gravity and acceleration. The utricle follows horizontal movement, and the saccule follows movement up or down. Both the utricle and saccule send constant input to the brain concerning head motion and position in all three dimensions in order to keep the head aligned properly and our bodies in balance.

The way these little organs actually work is yet one more marvel to keep us amazed. The utricle and saccule are filled with tiny calcium carbonate particles suspended in a thick fluid. Inside of them are also hair-like sensor cells. When the head moves, gravity causes the weight of the particles in the fluid to press upon the hairs, which in turn send signals down nerve fibers to the brain, and the brain interprets the motion. The brain can then tell whether only the head is in motion or the whole body. Input also comes to the brain from the eyes and muscles to make its assessments, but the vestibular system of the inner ear is the primary source of information for keeping the head and body in balance.

Simultaneously, the three semi-circular ducts are performing much the same function as the utricle and saccule. However, rather than having the primary focus on head movement, they monitor the movement of the entire body. The three semi-circular ducts are known as the superior duct, posterior duct, and external duct. These canals or ducts are all perpendicular to each other, so that they are aligned with all three spatial dimensions, taking into account any motion that is forward or backward, left or right, or up or down, or any combination of motions. These semi-circular canals operate like the utricle and saccule. They are fluid filled and have the hair-like sensory cells that react to movement by sending electrical impulses to the brain.

The inner ear is constantly working, performing all of these functions, whether we are aware of it or not. To maintain our sense of balance, we depend on the vestibular system to gather motion information and send it on to the brain. The brain then processes the information, making sense of all the competing signals, and sends out signals of its own to the muscles in order to keep us in balance.

When balance problems and ringing in ears symptoms are experienced together, Meniere's disease which accounts for nearly one percent of tinnitus cases is often indicated. Still, another tinnitus issue arises within the inner ear and it is much more common--namely, noise-induced damage to the tiny hair cells in the cochlea. Most noise-induced damage can be prevented easily by avoiding places where loud sounds are generated or by wearing ear protection in the form of ear muffs or ear plugs. For treating tinnitus caused by noise-induced damage or acoustic trauma, a good holistic tinnitus treatment regimen such as Tinnitus Miracle provides the best opportunity for lasting tinnitus relief.