It terminates in the eardrum which is technically known as the tympanic membrane. The purpose of the external ear is to transmit sounds from the outside world into the more internal parts of the auditory system. While one can simply think of the pinna and ear canal as a simple funnel for collecting sounds, in reality they perform some important functions. The pinna has various ridges and folds that act to reflect and absorb certain frequency components of the sound wave . Because the pinna is not circularly symmetric, sounds which come from different directions will have slightly different spectral characteristics.
Depending on these differences, there may be an effect on the neural functionality. The first difference to consider is the Young’s modulus of the nerve and the electrode. The electrode, which is made from polysilicon, has a Young’s modulus of around 155 GPa1 while the nerve itself has a Young’s modulus of around 580 kPa2. A large mismatch in Young’s modulus can lead to the electrode being encapsulated by non-neuronal cells as the body attempts to minimize the damage caused by having something stiff inserted into soft tissue. The difference in Young’s modulus interferes with the
EAR The human auditory system is one of the most intricate, miraculous, and an ingenious creation designed to transfer sound waves from environment to brain in a most efficient and precise manner. The ear can be described as both an analytic microphone and a microcomputer, sending sound impulses to the brain. Ear is capable of turning the tiniest disturbances to a form that brain can understand and doing so instantaneously, over an enormous range of pitch and loudness. Being extremely complicated organ, it performs dual function of balancing and perceiving sound.
A short history of olfaction theories 1. Molecular shape (“lock and key” model) Generally, odorants activate many olfactory receptors, as the receptors are more about the properties of the substance than the substance itself. A particular odorant will bond only to the receptors it corresponds to, enabling a person to identify the smell. Odorants and receptors can be imagined as a lock and key pair.
Transcranial magnetic stimulation (TMS) is a non-invasive tool for the electrical stimulation of neural tissue, including cerebral cortex, spinal roots, and cranial and peripheral nerves. TMS can be applied as single pulses of stimulation, pairs of stimuli separated by variable intervals to the same or different brain areas, or as trains of repetitive stimuli at various frequencies. Single stimuli can depolarise neurons and evoke measurable effects. Trains of stimuli (repetitive TMS) can modify excitability of the cerebral cortex at the stimulated site and also at remote areas along functional anatomical connections. Transcranial magnetic stimulation might provide novel insights into the pathophysiology of the neural circuitry underlying neurological and psychiatric disorders, be developed into
• The Hindbrain is the structure that connects the spinal cord to the brain. – The medulla is located directly above the spinal cord and controls many vital autonomic functions such as heart rate, breathing and blood
Once the sound waves have rounded the corner of the ear canal, they cause the eardrum to vibrate, stimulating the ossicles of the middle ear (tiny bones called the malleus, incus and stapes – otherwise known as the hammer, anvil and stirrup). These ossicles transmit the sound waves to the cochlea. (Bailey, 2013). The cochlea is a fluid-filled structure in the middle ear.
The sense of touch is the most perplexing of the five basic senses; some neurologists believe we have more. The touch sense, also known as somatosensation, refers to the body’s ability to interact with the environment, interpret external factors, and distinguish pain from pleasure through experience which allows the body to respond appropriately to various sensations. The sense of touch differs from the other senses of sight, sound, smell, and taste because it is not confined to one specific location. Instead, it occurs all over the body. The primary organ that the body uses for the sense of touch is the skin, the largest organ of the body as it covers the entirety of it.
However, Schlemm’s canal endothelial cells have been previously reported to play a significant role in aqueous humor outflow resistance (Underwood et al. 1999; Alvarado et al. 2005). Such uncertainties about the role of Schlemm’s canal endothelial cells in the resistance to the outflow of aqueous humor make it necessary to deeply investigate the function and properties of these
The feeling of stabbing pain in upper jaw and teeth and slowly radiating towards nose is due to defective function of the maxillary nerve. The nerve is the second branch of trigeminal nerve. The initiating or trigger point is the loss of sensory or motor function of the second branch of fifth cranial nerve (Richard & Sanders, 2010) The following are the cranial nerves that involve in regulation of functions of eye o Optic nerve: The sensory nerve is a second cranial nerve help in whole process of sight and vision. The nerve involves in the transmission of electrical signals from the various parts of eye to CNS (brain), then the brain send an appropriate response in the form of an image to see (the objects what we see around us).
Cochlear implants represent a relatively new approach to treating deaf and partially deaf peoples via surgical implantation of a device which receives sounds from the environment, and transmits them via electrical stimulation of the auditory nerve. The cochlear implant represents an effective way to treat the hearing impaired on a case-by-case basis, offering successful results to those who otherwise may never be able to hear. We must disregard the population who have had both positive and negative reactions to the surgery to understand the surrounding controversy, which does not focus on the efficacy and success of the cochlear implant on the recipient, but rather on the deaf culture and whether the use of such a device imposes a societal standard which marginalizes the hearing impaired and categorizes them as “disabled”.
Stimuli initiating a nociceptive response vary, but receptors and endogenous defence mechanisms in the periphery interact in a similar manner regardless of the insult. Chemical, mechanical, and thermal receptors, along with leucocytes and macrophages, determine the intensity, location, and duration of noxious events. Noxious stimuli are transduced to the dorsal horn of the spinal cord, where amino acid and peptide transmitters activate second-order neurones. Spinal neurones then transmit signals to the brain. The resultant actions by the individual involve sensory-discriminative, motivational-affective, and modulatory processes in an attempt to limit or stop the painful process.
7. What is the function of the somatosensory system? The somatosensory system is the part of the sensory system concerned with the conscious perception of touch, pressure, pain, temperature, position, movement, and vibration, which arise from the muscles, joints,
There once was a family at war, the fight took an emotional toll and the family almost fell apart. The reason for the feud was hearing. Hearing is a huge part of most people’s lives. We as a society tend to take it for granted. Those who are born without hearing are the only people who have a true understanding of what it’s like not to hear.