Sensory systems taste

Sensory systems Taste Levofloxacin ophthalmic solution 1.5% in 100 patients has been compared with ofloxacin ophthalmic... 

Sensory systems Taste Dysgeusia in a 78-year-old woman occurred after losartan was added to her antihypertensive treatment [54 ]. She described a constant unpleasant taste, which resolved within 2 weeks after replacement of losartan by amlodipine. 

The function of a sensory system is to select suitable modalities from the multitude presented by the environment, and translate them into corresponding modalities of sensory information that are then projected and processed into the various parts and finally submitted to the central processing-unit, the brain. A working hypothesis of the mechanism by which the taste system senses chemical compounds is that macromolecules that are... 

In this paper the term taste will refer to all the chemical sensory systems of the oral cavity and their sensations. These sensory systems are intimately involved in the selection of food items and in the regulation of food intake. As we shall see, there are a variety of different taste systems attuned to different chemical aspects of food. These taste systems perform an exact and elaborate analysis of the chemical constituents in the food we eat. 

Vertebrates possess three primary chemosensory systems gustation ( taste ), trigeminal, and olfaction ( smell ) but only one of these, the olfactory system, mediates responses to pheromones. Chemicals that stimulate the olfactory system are known as odorants and comprise one type of biological cue (any entity that stimulates a sensory system). Bouquets of odorants that can be discriminated as specific entities are termed odors. The olfactory system contains olfactory receptor neurons (ORNs) that comprise cranial nerve I and project directly to the forebrain. ORNs are now known to express only one to a few olfactory receptor proteins ( receptors ), which means that the chemoreceptive range of each neuron can be very narrow. The olfactory system also has several subcomponents including the vomeronasal organ, which is described below. 

Like taste, touch is a combination of sensory systems that are expressed in a common organ—in this case, the skin. The detection of pressure and the detection of temperature are two key components. Amiloride-sensitive sodium channels, homologous to those of taste, appear to play a role. Other systems are responsible for detecting painful stimuli such as high temperature, acid, or certain specific chemicals. Although our understanding of this sensory system is not as advanced as that of the other sensory systems, recent work has revealed a fascinating relation between pain and taste sensation, a relation well known to anyone who has eaten "spicy" food. 

Sensory systems (includes eyes, ears, taste)... 

How do our sensory systems work How are the initial stimuli detected How are these initial biochemical events transformed into perceptions and experiences We have already encountered systems that sense and respond to chemical signals—namely, receptors that bind to growth factors and hormones. Our knowledge of these receptors and their associated signal-transduction pathways provides us with concepts and tools for unraveling some of the workings of sensory systems. For example, 7TM receptors (seven-transmembrane receptors. Section 14.1) play key roles in olfaction, taste, and vision. Ion channels that are sensitive to mechanical stress are essential for hearing and touch. 

Smell, taste, vision, hearing, and touch are based on signal-transduction pathways activated by signals from the environment. These sensory systems function similarly to the signal-transduction pathways for many hormones. "These intercellular signaling pathways appear to have been appropriated and modified to process environmental information. 

In this chapter, we shall focus on the five major sensory systems found in human beings and other mammals olfaction (the sense of smell i.e., the detection of small molecules in the air), taste or gustation (the detection of selected organic compounds and ions by the tongue), vision (the detection of light), hearing (the detection of sound, or... 

Nature uses chemical signalling in sensory systems snch as taste and smell. The most important means for information processing in nature is based on information exchange between DNA and RNA our brain use signals relying on the behaviour of ions, etc. This... 

Schiffman, S. S. Changes in taste and smell with age Psychophysical aspects. In J. M. Ordy K. R. Brizzee, Eds., "Sensory Systems and Communication in the Elderly," (Vol. 6). Raven Press New York, 1979 pp. 227-246. 

Olfactory system is unique in that there are numerous receptors for each specific kind of odorants [91]. It is very peculiar compared to other sensory systems like vision, touch, or taste in which only a few kinds of receptors exist. Eugenol has a very distinctive odor that is usually remembered as dental clinic scent. The olfactory receptor that eugenol binds was identified in mice and named mOR-EG or 01fr73, a G-protein-coupled receptor with a seven-transmembrane domain that increases intracellular cAMP concentration upon activation [92]. 

Sensory systems Olfaction Alterations in taste and smell function, which are rare, have been reported for pyrazinamide when combined with other drugs. Reversible olfactory... 

Taste has generally been thought of as a relatively simple sense being composed of salt, sweet, sour, bitter, and umami sensations (Chapter 1). This simplification is not justified since it is clear that each basic taste sensation has many nuances. Furthermore, it is worthwhile to note that each taste sensation supports a different overall flavor perception. For example, if one uses citric acid in a food system, the citrus notes of the flavor will be enhanced. Phosphoric acid is intimately associated with certain cola flavors. Tartaric acid supports grape flavors. Thus, while each acidulant gives a unique sensory character (taste), it also influences our overall flavor perception (interaction to give an overall flavor perception). 

Olfaction is typically used as a label for all of the chemical senses with the exception of taste. This is an excessively general use of the term, and it leads to the misinterpretation of results. For example, mislabeling trigeminally mediated responding as olfactory is an error similar in magnitude and implication to mislabeling visually mediated behavior as auditory. As we discuss below, a variety of other sensory systems in the nasal and oral cavities respond to chemical stimuli and mediate different categories of behavior. 

Off-flavor or bitterness is usually reported for compounds such as creatine, creatinine and nucleotide bases. A mixture of several different types of compounds has been reported necessary to reconstruct meat flavors. This chemical complexity suggests that different sensory systems are being activated. Many of these compounds appear to exert their effects through human geniculate ganglion taste systems others obviously stimulate other oral chemoresponsive systems. 

Taste-active chemicals react with receptors on the surface of sensory cells in the papillae causing electrical depolarization, ie, drop in the voltage across the sensory cell membrane. The collection of biochemical events that are involved in this process is called transduction (15,16). Not all the chemical steps involved in transduction are known however, it is clear that different transduction mechanisms are involved in different taste quaUties different transduction mechanisms exist for the same chemical in different species (15). Thus the specificity of chemosensory processes, ie, taste and smell, to different chemicals is caused by differences in the sensory cell membrane, the transduction mechanisms, and the central nervous system (14). 

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