How Are Signals from the Receptors in the Mouth and Nose Used to Derive Our Perception of Taste - Essay Example

The receptors are contained in these taste buds where receptor cells are located and are composed of finger-like structures, called microvilli, through which dissolved chemicals collect and permeate from the saliva upon direct contact. In other words, the receptor sites are made to interact with the taste stimuli derived from the substances of varying chemical concentrations which may form ions during the dissolution process. At this stage, the chemicals in the receptor cells undergo stimulation and are converted into neural responses via a transduction mechanism.

It must be noted that while taste quality is encoded, most taste receptor cells respond to each of the four primary kinds of taste stimuli to a certain extent despite sensitivity differences. Once full conversion to neural responses is attained, the afferent nerve fibers (Chorda tympani, Glossopharyngeal, and Vagus) take the responsibility of transporting taste information generated from all taste buds along the regions of tongue and oral cavity to the brainstem that holds the nucleii. Then, the neural information is further carried to the thalamus with its own taste responsive cells after which the primary taste area in the parietal lobe of the cortex receives the sensory details which altogether make our perception of taste.

Cross-fiber and labeled line theories are proposed means in ascertaining how a brain manages to provide distinctions among a wide range of signals according to a variety of flavors attached with the substances taken initially. (II) How signals from the receptors in the nose are used to derive our perception of smell – On the other hand, since taste and smell are found to be closely linked and bear attributes that tend to interact by nature, the signals via receptors within the nose function in an analogous manner as those of the mouth in conveying, this time, a perception through the sense of smell.

However, unlike taste, no agreed set of primary odor qualities or sensations exist in this case and because the distinct odors are great in number, the relationship between the smell of a substance and its chemical properties is not readily identified. The action of gathering signals starts at an instant molecules enter the nasal cavity and are humidified by the baffles lying at the region just above the tongue. These inhaled molecules are received by the olfactory receptors designated in the olfactory epithelium.

More specifically, the odor molecules or odorants from the atmosphere are trapped onto the specialized odorant binding proteins in mucus and are later shifted to the ‘cilia’ or the finger-like projections containing the receptor sites on either end of an olfactory cell, where molecular substances are brought to interact with the membranous sites. Based on the ‘lock-and-key’ hypothesis, odorant molecules (keys) bind themselves to particular proteins in cilia membrane (locks) depending on the size and shape of the embedding molecules.

Consequently, a number of biochemical processes occur as such binding operation activates cell axon potentials. These potentials are later sent via the olfactory receptor cells to pass through the bone holes above the nasal cavity, developing the olfactory nerve which is connected to the olfactory bulb of the brain where odor impulses are further destined.