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.
There are several differences between the electrodes and the medium into which they will be inserted. 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.
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. The auditory system is highly complex and composed of three anatomical compartments, the external, middle and inner ear, which function as an entity.
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. SIGNAL TRANSDUCTION Action potentials (electrical signals) convey information along neurons.
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
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 sound waves are translated to fluid waves in the cochlea that are then sensed by nerves connected to fine hairs that float in the fluid and is then sent on to the brain for interpretation.
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.
2014) and results in the presence of pores, called “giant vacuoles”, inside the endothelial cells (Johnson 2006). Supporting such pressure gradient may imply the low resistance of this endothelium layer to aqueous humor flow (Zeng et al. 2010). 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.
Fifth cranial nerve (trigeminal nerve) is affected to show the episode. 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).