Noise pollution is considered one of the main problems in urban areas; moreover, excessive noise has been marked as one of the major pollutants in the work and living space (1)(2). Both urban and suburban areas have become increasingly noisy environments and the threshold limits are continually being exceeded. There can be negative auditory and extra-auditory health effects (3)(4). In order to fully understand the effects of noise one must first look into how we perceive it. The Merriam-Webster Medical Dictionary defines hearing as, “the act or power of apprehending sound” they further state that hearing is performed when sound waves are funneled from the outer ear through the ear canal to the ear drum, which causes a thin membrane to vibrate (5). Subsequently, these vibrations are transported through tiny bones, located in the middle ear, to the fluid of the inner ear. The vibrations stimulate hair cells, which convert these pulsations into electrical nerve currents. The currents are transported to the brain’s auditory center via the hearing nerve and thereby identified and interpreted as sound (5).
It is known that prolonged and continuous exposure to noise at high intensity causes NIHL (Noise Induced Hearing Loss) with damage of the hair cells of the inner ear as well as a hearing threshold shift and an impairment of communication (1). Although these auditory effects of noise on humans have been established, the non-auditory effects are still unclear. There are new emerging links between excessive noise exposure and CVD (cardiovascular disease) that could have serious effects on public health in noisy environments. Cardiovascular disease, manifested as hypertension, myocardial infarction, ischem...
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...ects that uses small antennae vibrations to measure sound (16).
Although the fly has an open circulatory system, the development of the circulatory and the auditory system of lies are very similar (17). In fact, the Society for Development Biology states that, “With the exception of the central nervous system, most of the structures of the adult fly develop during the larval period and take their final form during eclosion, the act of emerging from the pupal case”(18). This makes Drosophila a good model organism to study the effects of excessive noise on prenatal flies, as their development is similar to human’s, when regarding the cardiovascular system and auditory system (19).
Thus, Drosophila melanogaster serves as a model organism for both auditory and cardiovascular systems in humans for these reasons drosophila was selected as the model organism.
Barlow (1953) first postulated the existence of feature-sensitive ganglion cells in a frog’s retina based on an inhibitory-surround structure of the receptive field. He maintained that the “on-off” units of these cells triggered by the presence of a particular stimulus corresponded to certain behaviour in the frog. For example, presenting a spot of light in the visual field would cause certain neurons to fire in a particular ganglion cell, and in a live frog, would cause the frog to snap at the stimulus. Barlow concluded that these cells must be “fly detectors”. Lettvin et al. (1959) further examined the visual mechanisms of the frog and discerned fo...
Hearing allows us to take in noises from the surrounding environment and gives us a sense of where things are in relation to us. All those little folds on the outside of the ear, called the tonotopic organization, make it so sound waves in the air are directed to the ear canal, where they can be further processed. Once in the ear, the sound waves vibrate the ear drum, which tell the ear exactly what frequency it is sensing. The vibration of the ear drum is not quite enough to send a signal to the brain, so it needs to be amplified, which is where the three tiny bones in the ear come into play. The malleus or hammer, incus or anvil, and stapes or stirrup amplify this sound and send it to the cochlea. The cochlea conducts the sound signal through a fluid with a higher inertia than air, so this is why the signal from the ear drum needs to be amplified. It is much harder to move the fluid than it is to move the air. The cochlea basically takes these physical vibrations and turns them into electrical impulses that can be sent to the brain. This is...
Every organism on the world needs a little help surviving, and each organism has its special and unique helping hand. The California condor or, Gymnogyps californianus, for instance, it has a hooked beak so that they can dig into the carcasses left by previous predators. Unlike its close looking cousins like the eagle or vultures, the condors don’t have a good sense of smell so they depend on th...
Loud noises a common cause of hearing. Constant exposure to loud noises such as noises made by drilling equipments and very loud music, causes the gradual damage of the hair cells in cochlea. Exposure to thunderous noise of explosions can cause sudden hearing loss.
Thorne, P. R., Ameratunga, S. N., Stewart, J., Reid, N., Williams, W., Purdy, S. C., ... & Wallaart, J. (2008). Epidemiology of noise-induced hearing loss in New Zealand. NZ Med J, 121.
For any individual who either avidly listens to or performs music, it is understood that many melodies have amazing effects on both our emotions and our perception. To address the effects of music on the brain, it seems most logical to initially map the auditory and neural pathways of sound. In the case of humans, the mechanism responsible for receiving and transmitting sound to the brain are the ears. Briefly stated, the outer ear (or pinna) 'catches' and amplifies sound by funneling it into the ear canal. Interestingly, the outer ear serves only to boost high frequency sound components (1). The resonance provided by the outer ear also serves in amplifying a higher range of frequencies corresponding to the top octave of the piano key board. The air pressure wave travels through the ear canal to ultimately reach and vibrate the timpanic membrane (i.e.-- the eardrum). At this particular juncture, the pressure wave energy of sound is translated into mechanical energy via the middle ear. Here, three small bones, the ossicles, vibrate in succession to produce a unique pattern of movements that embodies the frequencies contained in every sound we are capable of hearing. The middle ear is also an important component in what music we actually keep out of our 'head'. The muscles grasping the ossicles can contract to prevent as much as two thirds of the sound from entering the inner ear. (1, 2)
Noise is ubiquitous in our environment. (Pediatrics , 1997) It is undesirable sound, unwanted sound. Sound is what we hear. It is vibration in a medium, usually air. Sound has intensity, frequency and duration. The ability to hear sounds at certain frequencies is more readily lost in response to noise. (Pediatrics , 1997). The further you are from sound the less effect you hear it but the more closer you are to sound the louder it is.
The objective of this experiment is to determine what genes are responsible for the white-eye color in two strains of Drosophila melanogaster, known as the common fruit fly. Drosophila is used as the experimental organism for many reasons which include its small size, easy maintenance, short 10 day generation time, and a fully sequenced genome. The characteristics of the wild type, which is the most common phenotype found in nature, include brick red eyes, long wings, gray/tan body, and smooth bristles. Of course, there are mutations that occur that cause specific traits to deviate from the wild-type phenotype. These traits include wing length, bristle shape, body color, and eye color.
According to Chapman et al., (2000), the loss of hearing appears to be a chronic issue through...
Noise (Noise induced hearing loss NIHL): Another occupational hazard that contributes to workplace injury is excessive noise. Excessive noise may have adverse effects, which include, high blood pressure, stress, reduced performance and noise induced hearing loss. While there are other factors contributing to NIHL, the shortage of prevention is a high contributor. Engineering controls is one way of reducing noise at its source (Nelson et al. 20...
The ear houses some of the most sensitive organs in the body. The physics of sound is well understood, while the mechanics of how the inner ear translates sound waves into neurotransmitters that then communicate to the brain is still incomplete. Because the vestibular labyrinth and the auditory structure are formed very early in the development of the fetus and the fluid pressure contained within both of them is mutually dependant, a disorder in one of the two reciprocating structures affects the (2).
Along with vision, hearing is one of the most important senses that humans have. We use it to communicate, learn, and stay aware of our environment. In fact, hearing is the only sense that never stops receiving sensory input. While all of our other senses become drastically less sensitive when we are sleeping, our brain still processes auditory information to awaken us the second something is wrong. Although this may have been more practically used before people slept safely in homes, it’s still useful for hearing a fire alarm or our alarm clock in the morning. We are able to hear by processing sound waves. This energy travels through the delicate structures in our ears to be transformed into neural activity so that we can perceive the sensory information we receive (Myers, 2010).
Car pollutants cause immediate and long-term effects on the environment. Car exhausts emit a wide range of gases and solid matter, causing global warming, acid rain, and harming the environment and human health. Engine noise and fuel spills also cause pollution. Cars, trucks and other forms of transportation are the single largest contributor to air pollution in the United States, but car owners can reduce their vehicle's effects on the environment. Car pollution is one of the major causes of global warming. Cars and trucks emit carbon dioxide and other greenhouse gases, which contribute one-fifth of the United States' total global warming pollution. Greenhouse gases trap heat in the atmosphere, which causes worldwide temperatures to rise.
The environment and health are very closely linked. The environment in which we inhabit and go about our daily lives, directly impacts on our physical, mental and social well-being. There are biological, chemical and physical factors that can affect human health in a physical and mental way. The World Health Organisation states that "health is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity" (WHO 1948), meaning that although many factors relating to health are associated with environmental pollution, they can also be caused by the environment in which we work and live in. The relationship between the environment and health, can however be quite complex. Human health is not only as a result of air, water and ground pollution, but also things such as food, genetics, life style and quality, which directly affect human susceptibility to illness, disease and possibly death. Disruptions to the environment, such as substance dispersal, climate change, acidification, ground pollution, photochemical air pollution and over fertilisation can also impact on human health. Therefore, there are direct and indirect links to the environment and health issues.
Hearing is known to be an automatic function of the body. According to the dictionary, hearing is, “the faculty or sense by which sound is perceived; the act of perceiving sound,” (“hearing…”). Hearing is a physical and involuntary act; therefore, unless one is born with a specific form of deafness, everyone has the natural ability to hear sounds. Sounds constantly surround us in our everyday environments, and because we are so accustomed to hearing certain sounds we sometimes don’t acknowledge them at all (or “listen” to them). The dictionary definition of listening is, “to give attention with the ear; attend closely for the purpose of hearing,” (“listening…”). This differs from hearing in that this is a voluntary action, and we have control over what we choose to listen to. As stated by William Seiler and Melissa Beall, “You don’t have to work at hearing; it just happens… Listening, on the other hand, is active and requires energy and desire,” (145).