The Eardrum and Ear is Very Complex
by Owen Borville
June 29, 2020
Biology
The eardrum in humans and mammals is very complex. It is so sensitive that sound wave induced vibrations cause it to move a small immeasurable amount, a width smaller than a 1/100 the width of a hydrogen molecule. The eardrum is capable of detecting pressure variations of less than one billionth of atmospheric pressure.
The ear's sensitivity is dependent on a gelatinous structure in the inner ear called the tectorial membrane, according to researchers at MIT. Nanoscale pores in that membrane help give us the sensitivity of the ear, and the way those nanopores control the movement of water within the gel. Tiny hairs that line the inner ear also help sense sound vibrations and differentiate between different frequencies. The tectorial membrane is thinner than a hair and is essentially a saturated sponge-like structure made mostly of water.
The tectorial membrane is an extracellular connective tissue that covers the mechanically-sensitive hair bundles of the sensory receptor cells in the inner ear. It occupies a strategic position, playing a key role in transforming sound to mechanical stimulation.
The outer ear consists of the pinna (also called the auricle), ear canal and eardrum.
The middle ear is a small, air-filled space containing three tiny bones called the malleus, incus and stapes but collectively called the ossicles. The malleus connects to the eardrum linking it to the outer ear and the stapes (smallest bone in the body) connects to the inner ear.
The inner ear has both hearing and balance organs. The hearing part of the inner ear and is called the cochlea which comes from the Greek word for ‘snail’ because of its distinctive coiled shape. The cochlea, which contains many thousands of sensory cells (called ‘hair cells’), is connected to the central hearing system by the hearing or auditory nerve. The cochlea is filled with special fluids which are important to the process of hearing.
The central hearing system consists of the auditory nerve and an incredibly complex pathway through the brain stem and onward to the auditory cortex of the brain.
The eardrum vibrations caused by sound waves move the chain of tiny bones (the ossicles – malleus, incus and stapes) in the middle ear transferring the sound vibrations into the cochlea of the inner ear.
This happens because the last of the three bones in this chain, the stapes, sits in a membrane-covered window in the bony wall which separates the middle ear from the cochlea of the inner ear.
As the stapes vibrates, it makes the fluids in the cochlea move in a wave-like manner, stimulating the microscopically small ‘hair cells’.
Remarkably, the ‘hair cells’ in the cochlea are tuned to respond to different sounds based on their pitch or frequency of sounds. High-pitched sounds will stimulate ‘hair cells’ in the lower part of the cochlea and low-pitched sounds in the upper part of the cochlea.
When each ‘hair cell’ detects the pitch or frequency of sound to which it’s tuned to respond, it generates nerve impulses which travel instantaneously along the auditory nerve.
These nerve impulses follow a complicated pathway in the brainstem before arriving at the hearing centers of the brain, the auditory cortex. This is where the streams of nerve impulses are converted into meaningful sound.
All of this happens within a small fraction of a second, or almost instantaneously after sound waves first enter our ear canals.
All of the complex parts of the ear in humans and mammals could not possibly have evolved by random accident and must have been the product of a design and creation event by a Powerful Creator.
Jonathan B. Sellon, Mojtaba Azadi, Ramin Oftadeh, Hadi Tavakoli Nia, Roozbeh Ghaffari, Alan J. Grodzinsky, Dennis M. Freeman. Nanoscale Poroelasticity of the Tectorial Membrane Determines Hair Bundle Deflections. Physical Review Letters, 2019; 122 (2) DOI: 10.1103/PhysRevLett.122.028101
Massachusetts Institute of Technology. "Mechanism helps explain the ear's exquisite sensitivity: A critical gel-like structure in the inner ear moves according to a sound's frequency, researchers find." ScienceDaily. ScienceDaily, 16 January 2019. <www.sciencedaily.com/releases/2019/01/190116110945.htm>.
Hearinglink.org
by Owen Borville
June 29, 2020
Biology
The eardrum in humans and mammals is very complex. It is so sensitive that sound wave induced vibrations cause it to move a small immeasurable amount, a width smaller than a 1/100 the width of a hydrogen molecule. The eardrum is capable of detecting pressure variations of less than one billionth of atmospheric pressure.
The ear's sensitivity is dependent on a gelatinous structure in the inner ear called the tectorial membrane, according to researchers at MIT. Nanoscale pores in that membrane help give us the sensitivity of the ear, and the way those nanopores control the movement of water within the gel. Tiny hairs that line the inner ear also help sense sound vibrations and differentiate between different frequencies. The tectorial membrane is thinner than a hair and is essentially a saturated sponge-like structure made mostly of water.
The tectorial membrane is an extracellular connective tissue that covers the mechanically-sensitive hair bundles of the sensory receptor cells in the inner ear. It occupies a strategic position, playing a key role in transforming sound to mechanical stimulation.
The outer ear consists of the pinna (also called the auricle), ear canal and eardrum.
The middle ear is a small, air-filled space containing three tiny bones called the malleus, incus and stapes but collectively called the ossicles. The malleus connects to the eardrum linking it to the outer ear and the stapes (smallest bone in the body) connects to the inner ear.
The inner ear has both hearing and balance organs. The hearing part of the inner ear and is called the cochlea which comes from the Greek word for ‘snail’ because of its distinctive coiled shape. The cochlea, which contains many thousands of sensory cells (called ‘hair cells’), is connected to the central hearing system by the hearing or auditory nerve. The cochlea is filled with special fluids which are important to the process of hearing.
The central hearing system consists of the auditory nerve and an incredibly complex pathway through the brain stem and onward to the auditory cortex of the brain.
The eardrum vibrations caused by sound waves move the chain of tiny bones (the ossicles – malleus, incus and stapes) in the middle ear transferring the sound vibrations into the cochlea of the inner ear.
This happens because the last of the three bones in this chain, the stapes, sits in a membrane-covered window in the bony wall which separates the middle ear from the cochlea of the inner ear.
As the stapes vibrates, it makes the fluids in the cochlea move in a wave-like manner, stimulating the microscopically small ‘hair cells’.
Remarkably, the ‘hair cells’ in the cochlea are tuned to respond to different sounds based on their pitch or frequency of sounds. High-pitched sounds will stimulate ‘hair cells’ in the lower part of the cochlea and low-pitched sounds in the upper part of the cochlea.
When each ‘hair cell’ detects the pitch or frequency of sound to which it’s tuned to respond, it generates nerve impulses which travel instantaneously along the auditory nerve.
These nerve impulses follow a complicated pathway in the brainstem before arriving at the hearing centers of the brain, the auditory cortex. This is where the streams of nerve impulses are converted into meaningful sound.
All of this happens within a small fraction of a second, or almost instantaneously after sound waves first enter our ear canals.
All of the complex parts of the ear in humans and mammals could not possibly have evolved by random accident and must have been the product of a design and creation event by a Powerful Creator.
Jonathan B. Sellon, Mojtaba Azadi, Ramin Oftadeh, Hadi Tavakoli Nia, Roozbeh Ghaffari, Alan J. Grodzinsky, Dennis M. Freeman. Nanoscale Poroelasticity of the Tectorial Membrane Determines Hair Bundle Deflections. Physical Review Letters, 2019; 122 (2) DOI: 10.1103/PhysRevLett.122.028101
Massachusetts Institute of Technology. "Mechanism helps explain the ear's exquisite sensitivity: A critical gel-like structure in the inner ear moves according to a sound's frequency, researchers find." ScienceDaily. ScienceDaily, 16 January 2019. <www.sciencedaily.com/releases/2019/01/190116110945.htm>.
Hearinglink.org
