ScienceThe first stagein olfactoryperception beginsin the mucus layerof different scent particlesestablish communicationwith them and regulatethe molecular traffic in themucus layer-reaffirmingthe fact of an astonishingcreation.In conclusion, there is anastonishing activity in thedepths of the mucus layerthat manages the scentperceivingregion in yournose. Countless processes, ofwhich you are unaware andcannot see with the nakedeye, proceed with perfectplanning and timing.because mucus productionis increased. If the thicknessof the mucus were any less,then your body’s immunesystem will be weakened andthe olfactory micro-hairs inthe mucus layers could easilybe damaged.The basic functions of mucushave been known for sometime. Among other things,it prevents drying insidethe nose and constitutesa defense against foreignchemical substances. Butonly recently was it realizedthat mucus has a mostorganized structure andconstitutes a most idealenvironment.xix Indeed,it is a very rich mixtureof proteins, enzymes,mucopolysaccharides,immunoglobulins and lipids.The first stage in olfactoryperception begins in themucus layer. In order forscent particles contact thereceptors in the micro-hairs,they must first pass throughthis stratum. At this stage,special connection proteinsin the mucus layer combinewith scent particles andserve them literally as guides.xx These proteins are still thesubject of research. Theyare thought to assist scentparticles and receptors tocome together and alsoprevent excessive numbersof scent molecules fromreaching the receptors.xxiWhat is certain is that theproteins recognize thousandsImagine yourself wanderingin a garden filled with lovelysmellingflowers and holdingthem up to your nose to smellthem, one by one. In orderfor new scent particles toreach the receptors in yournose, the old moleculesneed to be disposed of,or it will be impossible foryou to detect the smell ofthe second flower aftersmelling the first. Such aneventuality could haveunwelcome consequences,but it is prevented by certainenzymes within the mucus.To describe it in simplifiedterms, after a specific-butquite brief-length of time,the enzymes in questionalter the structures of thescent particles and convertthem to a state wherethey no longer stimulatethe receptors. Later, theseneutralized moleculesare sent to the stomachtogether with the mucusthat traps them, and arethus eliminated. Note thatit is not expert biochemicalengineers and scientistswho accomplish this, butenzymes with no mind orconsciousness. In addition,the enzymes in the mucusachieve this by constantlymaking new “decisions”.Naturally, enzymes cannotmanage such complicatedtasks all by themselves. Allthis takes place throughthe limitless knowledge andmagnificent creation of God.Wonderful Messengers:Scent CellsScent receptors are actuallynerve cells whose mainfunction is to carry to theolfactory bulb the messagestriggered by scent molecules.Views in the scientific worlddiffer as to their numbers.Some researchers put thefigure at 10 millionxxiii, andothers at around 50 million.xxiv Millions of scent cellsin the olfactory regionwhichis no larger than thesmallest postage stamp-arearranged in an astonishingregularity. If you possessedall technical means andwere asked to place millionsof cells in exactly the rightlocations, could you do it?Such a task would of coursebe impossible. After all theiryears of research, scientistshave been unable even todetermine the exact numberof cells, let alone set outmillions of them, showingthat this task is of courseimpossible.Within the scent cell itself,there is also a striking divisionof labor. As the well-knownresearcher Stuart Firesteinpoints out: “The olfactorysystem accomplishes itssensory tasks with biologicalmechanisms that arecommon to many signalingsystems. This special designquickly manifests itself indrawings prepared fromelectron microscopy images.(Figure 7) The olfactorycell consists of three mainsections, the cell body inthe middle, the micro-hairsknown as cilia at one end,60An Islamic Periodical Magazine - Issue No 18 June 2010
Scienceand a protrusion known asthe axon at the other. (Figure8) The cell body is wheremany complex activitiestake place, the cilia wherecontact is made with scentmolecules, and the axonwhere electrical signals aretransmitted.The number of micro-hairsat the end of the cell rangesbetween 10 and 30, and theirlengths between 0.1 and 0.15millimeters (0.0039 to 0.006inch).xxvi The differencebetween these scents hairsand similar ones in otherregions of the nose is thatthe former move and possessscent receptors. (Figure 9)In contrast to the other ciliain the body, the olfactorymicro-hairs are entirelyindependent structures.They assume the role of askeleton for the receptors.Close inspection shows themost productive design forthe micro-hairs, with a widearea for contact betweenscent molecules andreceptors being squeezedinto a very small region. Inaddition, latest research hasrevealed that each olfactorycell contains just one of athousand different types ofscent receptor,xxvii as we’llconsider later, in greaterdetail.Though the term cilia ormicro-hairs may suggestvery simple structures, thefact is that these termsdescribe only the shape ofthe structures in question.In fact, olfactory micro-hairspossess an incomparableand extraordinarycommunications technology.Scent molecules that dissolvein the mucus combinewith special receptors onthe scent micro-hairs. Therelationship between thescent molecule and thereceptor resembles thatbetween a lock and key. Asa result of molecular detailsthat have not yet been fullyclarified, a signal is formedwithin the scent-receptorcell. At this stage, a greatmany proteins and enzymesunfailingly discharge theresponsibilities placed uponthem.The process by whichscent-receptors turn thecharacteristics of scentmolecules into electricalsignals is rather complicated.At present, only two of thecommunication networks inthe scent-receptor cells areknown. In the very simplestof terms, the communicationcan be summarized asfollows:Let us first examine thecommunication establishedAn Islamic Periodical Magazine - Issue No 18 June 2010 61
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