Neurobiology of Harmony

This causes the round window to bulge outward into the middle ear. The scala vestibuli and scala tympani walls are now deformed with the pressure waves and the vestibular membrane is also pushed back and forth creating pressure waves in the endolymph inside the cochlear duct. These waves then causes the membrane to vibrate, which in turn cause the hairs cells of the spiral organ to move against the tectorial membrane. The bending of the stereo cilia produces receptor potentials that in the end lead to the generation of nerve impulses. The External or Outer Ear - comprises of the auricle or pinna which is the fleshy part of the outer ear.

In the inner ear (cochlea) the sound is converted into neural activity. Basilar membrane acts as a divider of two fluids (scala media and the scala tympani) and the hair cells pick up movement in order to send a signal to the brain to interpret the sound. ii. The organ of corti is an extremely sensitive area of the cochlea. It transforms pressure waves into action potentials iii.

The vibrations are let off by the source, and this leads to something such as an ear to pick up the noise. Once the detector has picked up the wave, the wave must be ... ... middle of paper ... ...s able to process sound from the faintest of noise to the obnoxiously loud noises without hesitation. The complexities of the ear and how it is able to pick up sound waves is an amazing feat of creation. Bibliography: Henderson, Tom. "Sound is a Pressure Wave."

From this point, vibration of the connective membrane (oval window) transforms mechanical motion into a pressure wave in fluid. This pressure wave enters and hence passes vibrations into the fluid filled structure called the cochlea. The cochlea contains two membranes and between these two membranes, are specialized neurons or receptors called Hair cells. Once vibrations enter the cochlea, they cause the lower membrane (basilar membrane) to move in respect to the upper membrane (i.e. --the tectorial membrane in which the hair cells are embedded).

The vibrations cause changes in pressure of the medium and speed is able to change as the function of medium, while it can also stimulate mechanoreceptors on occasion. There are many different components of sound waves. The frequency is the number of cycles of sound waves completed per second. The wavelength is the distance between the same points on two successive waves. The amplitude is the height of the wave and the complexity is the interaction of many different waves.

. But here, we will only consider the transduction of sound. The cochlea is filled with hair cells that are extremely sensitive and depolarize with only slight perturbations of the inner ear fluid. At the point of depolarization, a neural signal is transmitted and on its way to the brain. This nerve impulse travels to the auditory nerve (8th cranial nerve), passes through the brainstem, and then reaches the branched path of the cochlear nucleus: the ventral cochlear nucleus or the dorsal cochlear nucleus.

These sound waves cause the eardrum to vibrate. The vibrations are caught by the middle ear, a set of small bones, which transfer the vibrations to the cochlea (inner ear). Here, the sound waves are converted to neural impulses. The neural network in the human brain decodes information from both ears. Within the cochlea resides a basilar membrane, a supporting structure for the cochlea nerve.

Compression and rarefaction of particles forming sound waves. Retrieved 23/02/14 from Popular Science Monthly Volume 13 What distinguishes sound waves from most other waves is that humans easily can perceive the frequency and amplitude of the wave. The frequency governs the pitch of the note produced, while the amplitude relates to the sound le... ... middle of paper ... ...a wide movement radius and will hence have shorter and more frequent excursions, it is not very effective at generating low-frequency waves. A woofer is therefore often necessary to cover the whole sound spectre. Furthermore, the speakers need to be plugged directly into a power supply, making room placement more difficult (HowStuffWorks.com, 2001).

Another way to improve the passive flow is to insulate the axonal membrane with myelin. This reduces the amount of current that would otherwise leak out of the axon and increases the distance that the current can flow passively. Myelination, aka axon insulation, increases action potential conduction up to 150m/s compared to 0.5-10m/s conduction velocities of unmyelnated axons! Speedy delivery of current (information) along axons is also due to the nodes of Ranvier. Nodes of Ranvier are gaps between insulated portions of the axon.

Our auditory system is one of our ‘gates’ to the outer world. It helps us pick up sound stimuli from our environment, transduce these stimuli into neural impulses and finally, carry these impulses to specific locations in the brain. In fact, its basic function, if we could summarize that, is the transduction of mechanical energy (that is, those sound vibrations in the air) into electrical energy (electrical pulses in the brain). Now… When we say ‘mechanical energy’ we mean a sound wave that reaches our head. This sound wave is nothing more than changes in air pressure, that is caused when a sound source transmits sound.