46

Yes, we can. By means of bone conduction we can hear up to 50 kHz, and values up to 150 kHz have been reported in the young (Pumphrey, 1950). However, it is indeed generally agreed that 20 kHz is the upper acoustical hearing limit through air conduction. The reason for this is debated, but the transfer function of the ossicle chain in the middle ear is a ...


16

A quick diagram to point out to people who may not know what Eustachian tubes are (#2). In order for the aromatic molecule to reach the olfactory bulb, it would first have to get through the Tympanic Membrane (#22) [a.k.a. - Eardrum]. The Tympanic Membrane is water/airtight unless pierced. So, while it's plausible that an aromatic molecule could travel ...


12

The only sensible answer to these questions is "sometimes". The reason: even a simple monotone must be described by both frequency and amplitude. Any frequency can cause harm with enough amplitude, and any frequency can be harmless when the amplitude is low enough. If you want to actually quantify the damage, you'll need something like an equal-loudness ...


10

There is no direct link between the capillaries in the sinuses and the ear. The Eustachian tubes drain the middle ear (between the eardrum and the inner ear) into the nasopharynx, the part of the throat that is just behind the nose. The para-nasal sinuses drain into the nasal passages themselves at different points. The sinuses and middle ear constantly ...


8

Although tinnitus is usually described as a ringing in the ear, there's a whole range of tunes, buzzes, whooshing sounds, humming and hissing sounds that are described of as tinnitus. The sounds can either genuinely be there or be perceived to be there. If it is genuinely there it suggests muscles ate at play or some blood vessel disease if the sounds are in ...


8

If all the processes through which a signal passes are linear, then it makes sense to speak in terms of a maximum useful-content frequency. If a signal passes through non-linear stages, however, it is possible that frequency content which would in and of itself be above the range of hearing, may interact with other frequency content which is also above that ...


8

I will provide an answer in 2 parts. The first part is a theoretical approach based on the absolute possible minimum (my original answer). The second part focuses on experiments in the peripheral auditory system (added edited answer). PART I: Absolute theoretical minimum (original answer) As you inquire about electrical signals in the auditory human system ...


7

Acoustically, we hear better in the 2-5 kHz range because our auditory canal resonates in that range (specifically, around 3 kHz). Our ear looks something like this (U Miami): The auditory canal is part of the outer ear, which amplifies sound so that it can be converted into electrochemical signals by the middle and inner ear. We hear better in the 2-5 kHz ...


7

It is related to Eustachian tube. It links the back of throat and the middle ear and allows air pressure to equalize in the middle ear. When you yawn air pressure goes up in this and it bends the ear drum and causes impair hearing (notice, just impair and not stop). Yawning also helps to open Eustachian tube.


7

If you are talking about sound damaging the sound sensing organs in the ear, analogous to an ultrasonic heavy metal concert, I've found an interesting report just on this topic. For ultrasonic components above 20 kHz, the limits were set to avoid hearing damage in the audible (lower) frequencies. One-third-octave band levels of 105-115 dB were observed ...


6

As quoted from the wikipedia page on Earwax: Cerumen [earwax] is produced in the outer third of the cartilaginous portion of the human ear canal. It is a mixture of viscous secretions from sebaceous glands and less-viscous ones from modified apocrine sweat glands. The primary components of earwax are shed layers of skin, with 60% of the earwax ...


5

+1 for giving a solid answer to @AP, but being older I've had friends who have had tinnitus and I'd like to add some notes to try to flesh this out a bit. I don't think tinnitus is the result of nerve damage usually. Nearly everybody experiences episodic tinnitus at one point or another. When exposed to a loud sound or a blow to the head can cause it. ...


5

Yes, of course they can. What happens when your ears feel 'full' like on an aeroplane is that the air pressure in the middle ear is different from the air pressure outside. When you 'pop' your ears, you push open the Eustachian tubes that connect the middle ear to the throat and make the pressure equal. No matter what the air pressure, the air still conducts ...


5

Tympanic displacement measurement (TMD) is a well studied field using hi-tech tools (i.e. stroboscopic holography), and complex units: Vm = volume displacement in nl nanoLiters. μm/pa (UDTF) = Linear tympanic membrane displacement is known as the umbo displacement transfer function. The graph on the left gives you a value of 0.8-0.6 = 0.2 microns: The ...


5

I'm able to create rumbling in my ears at will. Unlike the poster of the video, I don't need to yawn to do so; I can do it without my face appearing to move. I actually discovered this alongside another ability of mine when I was little: the ability to create warmth flowing from the base of my neck outwards into the rest of my body. After some research I ...


4

Basically you are asking: (1) does the low-pitch noise affect my hearing sensitivity; (2) has the noise aggravated hearing loss acquired earlier in life; (3) if the noise can induce stress and (4) if the noise may cause tinnitus (kind of a hidden question). (1) Is the ventilator noise damaging?: Noise-induced hearing loss typically occurs at high sound ...


4

Spontaneous ringing is caused by When the outer hair cells put energy back into the vibration, which is known as positive feedback. The process is meant to amplify very quiet sounds more so than loud ones. Normally this works, and you would not notice the sound. But occasionally, the amplification level of one or more outer hair cells will go awry and as a ...


4

The reason that cartilage rarely is able to regenerate is that it is poorly vascularized and innervated. It doesn't have its own blood supply to deliver signaling molecules that promote regeneration and repair after injury. There has been some recent progress on getting the body to repair and replace cartilage with lab created biogels detailed here.


4

Up front - I have never heard of this term and I could not find information on the interauricular line. The only thing I was able to dig up was the term auricular line, which is (Fig. 1): [The] [l]ine pass[ing] perpendicular to the anthropological baseline, through the cent[er] of the external auditory meatus. Fig. 1. Auricular line. source: Radiology ...


4

The outer ear canal ends at the eardrum, and beyond that is the middle ear. The middle ear is normally a closed chamber, but can be connected to the outside world by flexing the jaw or muscles related to. The flexing opens the Eustachian tube, which runs from the middle ear to the back of the nose and mouth. Hearing is best when the air pressure in the ...


4

Yes, humans have lost the ability to move their ears toward sounds like many other animals such as cats and rabbits. It is thought that our ancestors lost the ability to move their ears around 30 million years ago when Ear size decreased and the associated musculature changed 1 (Steven Hackley). A review from Steven Hackley outlines the evidence that ...


3

Preamble. There is a lot of misunderstood science here and you are more than right for questioning the lecturers interpretation of these energy values; something the other answers do not discuss. The problem arises from a dodgy reference and a lot of conjecture. In summary. Light and sound cannot be compared energetically in a biological context. Our ears ...


3

Short answer Hearing threshold is 0 dB SPL at 1 kHz, and pain threshold is around 125 dB SPL at that frequency. Background Loudness thresholds depend on acoustic frequency (pitch), as depicted in the following figure: Loudness contours in human. Source: Stanford Uni When expressed in dB sound pressure level (dB SPL) the threshold of pain is approximately ...


3

The endolymph inside the ear, like any kind of matter, has mass and so is subject to inertia. This means any change in speed and direction will be resisted. The ear and semicircular canals themselves are fairly solidly connected to the rest of the body and so accelerate smoothly. But since endolymph is fluid, it cannot be brought up to speed as fast, so ...


3

This phenomenon is called Ototoxicity, which literally means "toxic for the ear". Mostly the cochlea or the auditory nerve are affected and almost all these cases are connected to medications as gentamicin or cisplatin. The reasons for this are that the cells are either driven into apoptosis or necrosis. This is caused by destroying mitochondria and ...


3

Short answer Our ears are most sensitive to the mid-frequencies. Background There are different ways of assessing sound level. The physical one simply determines the physical sound pressure level (SPL) in which all the frequencies weigh equally. This is referred to as C-weighting and is expressed in dB SPL. Our ears, however, are most sensitive to ...


3

The Wikipedia article is quite good. In brief, as you state, the wave phase can be used only to localise sounds in the plane of the ears. To have an approximation of the position in the median plane (above-below/front-back), we use asymmetries that distort the sound differently at different frequencies. In humans, it seems that these asymmetries and their ...


3

Localization along the azimuth (horizontal left-right axis) is mediated by various processes: 1) First, there is the head shadow effect, which means that sounds from the left reach the right ear (AD) in an attenuated state relative to the left ear (AS) due to the presence of bone and other tissues. This difference is picked up by the superior olive (SO). ...


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