{"id":36519,"date":"2019-08-31T03:20:25","date_gmt":"2019-08-31T00:20:25","guid":{"rendered":"https:\/\/bilimvegelecek.com.tr\/?p=36519"},"modified":"2019-08-29T17:03:13","modified_gmt":"2019-08-29T14:03:13","slug":"duyu-organlarimizin-isleyisi-goz-ve-gorme-olayi","status":"publish","type":"post","link":"https:\/\/bilimvegelecek.com.tr\/index.php\/2019\/08\/31\/duyu-organlarimizin-isleyisi-goz-ve-gorme-olayi","title":{"rendered":"Duyu organlar\u0131m\u0131z\u0131n i\u015fleyi\u015fi: G\u00f6z ve g\u00f6rme olay\u0131"},"content":{"rendered":"

\u00c7evremizi duyular\u0131m\u0131z yoluyla alg\u0131l\u0131yoruz. Bu nedenle duyular\u0131m\u0131z\u0131 olu\u015fturan veya bir duyunun olu\u015fumuna yard\u0131mc\u0131 olan organlar\u0131n \u00e7ok \u00f6nemli i\u015flevleri var. Bu organlar temel i\u015flevlerini yerine getirerek g\u00f6rmemizi, i\u015fitmemizi, koku almam\u0131z\u0131, tat almam\u0131z\u0131 ve nesneleri hissetmemizi sa\u011fl\u0131yor. Peki, bu yap\u0131lar nas\u0131l i\u015fliyor, hangi mekanizmalar yoluyla i\u015flevlerini yerine getirebiliyor? \u0130lk olarak g\u00f6rme organ\u0131 olan g\u00f6z ve g\u00f6rme olay\u0131 \u00fczerinde dural\u0131m.<\/em><\/p>\n

G\u00f6rmeyi sa\u011flayan organ olan g\u00f6z, pek \u00e7ok farkl\u0131 katmandan olu\u015fur. Bu katmanlar\u0131n baz\u0131lar\u0131n\u0131n beyinle ba\u011flant\u0131 olu\u015fturmas\u0131 ile birlikte, g\u00f6z taraf\u0131ndan \u00e7evremizden toplanan sinyaller beyne iletilir. Beyne iletilen sinyallerin olu\u015fturdu\u011fu g\u00f6rsel, \u00e7e\u015fitli mekanizmalar\u0131n i\u015flemesinin ard\u0131ndan g\u00f6r\u00fcnt\u00fcye d\u00f6n\u00fc\u015f\u00fcr. Bu noktada, mekanizmalar\u0131 anlamak i\u00e7in g\u00f6z\u00fcn katmanlar\u0131n\u0131 irdeleyelim. G\u00f6z, temelde \u00fc\u00e7 tabakadan olu\u015fur: G\u00f6z ak\u0131 ve korneadan olu\u015fan d\u0131\u015f tabaka, iris ve g\u00f6z merce\u011finden olu\u015fan orta tabaka, beyne giden sinir a\u011flar\u0131n\u0131n bulundu\u011fu a\u011f tabakay\u0131 ta\u015f\u0131yan i\u00e7 tabaka.<\/p>\n

G\u00f6z\u00fcn d\u0131\u015f tabakas\u0131na bak\u0131\u015f
\n<\/strong>G\u00f6rme organ\u0131 olan g\u00f6z\u00fcn en d\u0131\u015f katman\u0131 olan ve g\u00f6z yuvarl\u0131\u011f\u0131n\u0131 saran tabakaya d\u0131\u015f tabaka ad\u0131 verilir. Bu tabaka, saydam tabaka olarak bilinen kornea ve g\u00f6z ak\u0131 olarak bilinen sklera yap\u0131lar\u0131ndan olu\u015fur. Bu yap\u0131lar\u0131n \u00e7ok \u00e7e\u015fitli g\u00f6revleri olmakla birlikte \u00f6zellikle kornea yap\u0131s\u0131n\u0131n g\u00f6z hastal\u0131klar\u0131nda olduk\u00e7a b\u00fcy\u00fck bir rol\u00fc vard\u0131r. Bu yap\u0131lar\u0131 tek tek inceleyerek g\u00f6rme olay\u0131ndaki \u00f6nemlerini anlayal\u0131m. \u0130lk olarak kornea, g\u00f6ze gelen \u0131\u015f\u0131k sinyallerinin odaklanmas\u0131nda b\u00fcy\u00fck bir rol oynar, bu yap\u0131 g\u00f6z\u00fcn toplam odaklama kapasitesinin y\u00fczde 65-75\u2019inden sorumludur. G\u00f6z merce\u011fi ve kornea, g\u00f6rme olay\u0131n\u0131n ilk basama\u011f\u0131 olan \u0131\u015f\u0131nlar\u0131n toplanmas\u0131nda uyum halinde \u00e7al\u0131\u015f\u0131r. I\u015f\u0131k \u0131\u015f\u0131nlar\u0131 korneaya \u00e7arpt\u0131\u011f\u0131nda, kornea \u0131\u015f\u0131nlar\u0131 g\u00f6z merce\u011fine denk gelecek \u015fekilde b\u00fcker. Bu \u0131\u015f\u0131k k\u0131r\u0131n\u0131m\u0131 yoluyla ayarlanan objektif, \u0131\u015f\u0131nlar\u0131n g\u00f6rme olay\u0131n\u0131n ger\u00e7ekle\u015ftirilmesinde olduk\u00e7a b\u00fcy\u00fck bir role sahip olan retinan\u0131n \u00fczerine d\u00fc\u015fmesini sa\u011flar. Bu noktada kornea yoluyla sa\u011flanan \u0131\u015f\u0131k k\u0131r\u0131n\u0131m\u0131 olay\u0131, kameralar\u0131n foto\u011fraf \u00e7ekme prensiplerine benzerlik ta\u015f\u0131maktad\u0131r.<\/p>\n

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G\u00f6z\u00fcn d\u0131\u015f tabakas\u0131, kornea ve sklera yap\u0131lar\u0131ndan olu\u015fur.<\/figcaption><\/figure>\n

Ayr\u0131ca g\u00f6z\u00fc \u00e7e\u015fitli darbelerden korumak, g\u00f6z\u00fc nemli tutmak, g\u00f6z \u00fczerindeki (kornea tabakas\u0131 \u00fczerindeki) yaralar\u0131n iyile\u015fmesine yard\u0131mc\u0131 olmak i\u00e7in g\u00f6zya\u015flar\u0131 korneaya akar. Bu noktada ifade edilebilir ki kornea, mikroplara ve g\u00f6ze zarar verebilecek di\u011fer par\u00e7ac\u0131klara kar\u015f\u0131 engelleyici bir g\u00f6rev g\u00f6r\u00fcr. Bu koruyucu g\u00f6rev tek ba\u015f\u0131na kornea yoluyla yerine getirilebilecek bir g\u00f6rev de\u011fildir. Kornea bu g\u00f6revi, g\u00f6z kapaklar\u0131, kirpikler, g\u00f6zya\u015f\u0131 ve g\u00f6z ak\u0131 yap\u0131s\u0131 ile payla\u015f\u0131r. Son olarak kornea, g\u00fcne\u015ften gelen zararl\u0131 UV \u0131\u015f\u0131nlar\u0131n\u0131 engelleyen bir filtre g\u00f6revi g\u00f6r\u00fcr; g\u00f6z merce\u011fi ve retina \u00fczerinde UV \u0131\u015f\u0131nlar\u0131ndan kaynakl\u0131 olarak meydana gelebilecek yaralanmalara kar\u015f\u0131 koruma sa\u011flar. Kornea yap\u0131s\u0131 kan damar\u0131 i\u00e7ermez.<\/p>\n

\u0130kinci olarak bu tabakan\u0131n di\u011fer bir unsuru olan g\u00f6z ak\u0131na yani sklera yap\u0131s\u0131na odaklanal\u0131m. Sklera, g\u00f6z\u00fcn i\u00e7 bas\u0131nc\u0131n\u0131n dengelenmesinde i\u015f g\u00f6rerek g\u00f6z\u00fcn \u015feklini korur; yaz\u0131 i\u00e7erisinde bahsedildi\u011fi gibi d\u0131\u015f darbelere ve kornea y\u0131rt\u0131lmas\u0131 gibi ciddi hasarlara kar\u015f\u0131 da g\u00f6z\u00fc korur. G\u00f6z\u00fcn hareketini kontrol eden g\u00f6z d\u0131\u015f\u0131 kaslar i\u00e7in bir ba\u011flant\u0131 sa\u011flamas\u0131 a\u00e7\u0131s\u0131ndan sklera, olduk\u00e7a \u00f6nemli g\u00f6revlere de sahiptir. Bu ba\u011flamda g\u00f6z k\u00fcresinin kuvvetini ve esnekli\u011fini olu\u015fturur. Sklera yap\u0131s\u0131n\u0131 g\u00f6rsel olarak da tan\u0131mlayacak olursak, g\u00f6z ak\u0131 dedi\u011fimiz g\u00f6z\u00fcn beyaz k\u0131sm\u0131 sklera ismi verilen bu yap\u0131d\u0131r. G\u00f6z k\u00fcresinin y\u00fczey alan\u0131n\u0131n y\u00fczde 80\u2019inden fazlas\u0131n\u0131 sklera yap\u0131s\u0131 olu\u015fturur. Bu yap\u0131, g\u00f6z\u00fcn di\u011fer yap\u0131lar\u0131na k\u0131yasla etkin de\u011fildir ve s\u0131n\u0131rl\u0131 bir kan kayna\u011f\u0131na sahiptir. Baz\u0131 kan damarlar\u0131 g\u00f6z i\u00e7ine da\u011f\u0131l\u0131mlar\u0131 s\u0131ras\u0131nda sklera yap\u0131s\u0131ndan ge\u00e7erler ancak bu ge\u00e7i\u015f, damarlar\u0131n sklera yoluyla ta\u015f\u0131nd\u0131\u011f\u0131 anlam\u0131na gelmedi\u011fi i\u00e7in sklera kan damarlar\u0131ndan yoksun bir yap\u0131 olarak kabul edilir.<\/p>\n

G\u00f6z merce\u011fi ve iris yap\u0131s\u0131, orta tabakada bulunur
\n<\/strong>Orta tabaka, d\u0131\u015f tabakan\u0131n i\u00e7 k\u0131sm\u0131nda yer al\u0131r ve d\u0131\u015f tabakan\u0131n aksine k\u0131lcal damarlarca zengin bir yap\u0131ya sahiptir. Bu tabaka i\u00e7erisinde de \u00f6ne \u00e7\u0131kan iki yap\u0131 bulunur: G\u00f6ze rengini veren, \u0131\u015f\u0131k \u0131\u015f\u0131nlar\u0131n\u0131 toplayan iris ve g\u00f6rme olay\u0131nda i\u015flevsel bir yap\u0131 olan g\u00f6z merce\u011fi. \u0130ris yap\u0131s\u0131, g\u00f6z\u00fcn korneas\u0131n\u0131n arkas\u0131nda bulunan d\u00fcz, halka \u015feklindeki zars\u0131 yap\u0131d\u0131r. Bu yap\u0131n\u0131n ortas\u0131nda g\u00f6zbebe\u011fi denilen, b\u00fcy\u00fckl\u00fc\u011f\u00fc \u0131\u015f\u0131nlara ba\u011fl\u0131 olarak ayarlanan dairesel a\u00e7\u0131kl\u0131k bulunur. \u0130ris yap\u0131s\u0131, ki\u015filerde g\u00f6z renginin ifade edildi\u011fi yap\u0131d\u0131r. G\u00f6z renginin nas\u0131l d\u00fczenlendi\u011fi \u015f\u00fcphesiz ba\u015fka bir yaz\u0131n\u0131n konusunu olu\u015fturur, bu nedenle irisin bu yaz\u0131 kapsam\u0131ndaki temel g\u00f6revi, g\u00f6ze giren \u0131\u015f\u0131k miktar\u0131n\u0131n d\u00fczenlenmesi olacakt\u0131r. I\u015f\u0131k miktar\u0131n\u0131n olmas\u0131 gerekenden fazla veya az olmas\u0131, g\u00f6rme olay\u0131n\u0131n ger\u00e7ekle\u015fmesini engelleyebilir. \u0130\u015fte iris yap\u0131s\u0131 bu noktada devreye girer. \u0130ris yap\u0131s\u0131 g\u00f6z bebe\u011fi ile uyumlu \u00e7al\u0131\u015f\u0131r ve \u0131\u015f\u0131k miktar\u0131na g\u00f6re boyutunu ayarlayarak toplanan \u0131\u015f\u0131n miktar\u0131n\u0131 d\u00fczenler. Bu \u00e7al\u0131\u015fma \u015fekli, beyin taraf\u0131ndan kontrol edilir ve bu yolak iste\u011fe ba\u011fl\u0131 olmaks\u0131z\u0131n \u00e7al\u0131\u015f\u0131r.<\/p>\n

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Orta tabakada bulunan iris yap\u0131s\u0131<\/figcaption><\/figure>\n

Orta tabakan\u0131n bir di\u011fer \u00f6nemli eleman\u0131 g\u00f6z merce\u011fidir. G\u00f6z merce\u011fi, iris yap\u0131s\u0131n\u0131n arkas\u0131nda bulunur. Kornea taraf\u0131ndan k\u0131r\u0131lan ve iris taraf\u0131ndan emilen \u0131\u015f\u0131k \u0131\u015f\u0131nlar\u0131, g\u00f6z merce\u011fine d\u00fc\u015fer ve mercek yoluyla k\u0131r\u0131lan \u0131\u015f\u0131nlar, a\u011f tabaka \u00fczerine d\u00fc\u015f\u00fcr\u00fcl\u00fcr. Bu noktada g\u00f6z uyumunu sa\u011flayan bir ba\u015fka mekanizmada etkin olarak \u00e7al\u0131\u015f\u0131r. Mercek boyutunu ayarlayan kaslar, g\u00f6ze gelen \u0131\u015f\u0131\u011f\u0131n miktar\u0131na ba\u011fl\u0131 olarak kas\u0131l\u0131p gev\u015feme hareketleri yaparak mercek kal\u0131nl\u0131\u011f\u0131n\u0131 ayarlar. Bu noktada mercek olduk\u00e7a \u00f6nemli bir i\u015flevi yerine getirir. Mercekte ya\u015fanan herhangi bir sorun g\u00f6rmeyi ciddi derecede etkiler. G\u00f6rme bozukluklar\u0131n\u0131n b\u00fcy\u00fck bir k\u0131sm\u0131 g\u00f6z merce\u011finin \u00e7al\u0131\u015fma \u015fekli ile alakal\u0131d\u0131r. G\u00f6z merce\u011finin \u00e7al\u0131\u015fma \u015feklinin d\u00fczenlenmesi i\u00e7in optik biliminin \u00f6nc\u00fcl\u00fc\u011f\u00fcyle \u00e7e\u015fitli iyile\u015ftirmeler (g\u00f6zl\u00fck, lens vb.) yap\u0131lmaktad\u0131r.<\/p>\n

G\u00f6rsellere ili\u015fkin bilgiler, fotoresept\u00f6rler yoluyla i\u015flenir
\n<\/strong>\u0130\u00e7 tabakada g\u00f6rev yapan retina, g\u00f6z\u00fcn arka k\u0131sm\u0131nda bulunan a\u011fs\u0131 bir tabakad\u0131r. Optik sinirin yak\u0131n\u0131nda konumlanm\u0131\u015ft\u0131r. Temel g\u00f6revi, g\u00f6z merce\u011fi taraf\u0131ndan odaklanan \u0131\u015f\u0131nlar\u0131 alarak optik sinire iletilecek sinyallere d\u00f6n\u00fc\u015ft\u00fcrmektir. Retina i\u00e7erisinde bulunan \u0131\u015f\u0131\u011fa duyarl\u0131 resept\u00f6rler, mercek taraf\u0131ndan odaklanan \u0131\u015f\u0131\u011f\u0131n \u00f6zelliklerinin ay\u0131rt edilmesini sa\u011flarlar. Bu fotoresept\u00f6rler, \u0131\u015f\u0131k yo\u011funlu\u011fu ve renk gibi temel \u00f6zellikleri tespit etmekle g\u00f6revli h\u00fccrelerdir. Retina ise bu fotoresept\u00f6rler yoluyla toplanan bilgileri i\u015fler ve bu bilgileri optik sinire g\u00f6nderir.<\/p>\n

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Retinada bulunan fotoresept\u00f6rler, \u0131\u015f\u0131\u011f\u0131n \u00f6zelliklerinin ay\u0131rt edilmesini sa\u011flar<\/figcaption><\/figure>\n

Retina, g\u00f6rme olay\u0131 s\u0131ras\u0131nda hayati bir role sahiptir. Bu nedenle retinada ya\u015fanacak herhangi bir hasar, kal\u0131c\u0131 g\u00f6rme kayb\u0131na neden olabilir. \u0130\u00e7 tabakay\u0131 b\u00fct\u00fcn\u00fcyle olu\u015fturan a\u011f tabakada bulunan bu fotoresept\u00f6rler, \u00e7ubuk ve konik resept\u00f6rleri olarak adland\u0131r\u0131l\u0131r. Bu resept\u00f6rlerden \u00e7ubuk \u015feklinde olanlar b\u00fcy\u00fck oranda siyah-beyaz g\u00f6r\u00fc\u015f\u00fc ve cisimlerin \u015feklinin alg\u0131lanmas\u0131nda i\u015fleve sahipken, koni h\u00fccreleri renkli g\u00f6r\u00fc\u015f\u00fc sa\u011flarlar. Bu noktada a\u011f tabaka ile ili\u015fkili olan birka\u00e7 yap\u0131ya da de\u011finmek gerekir. Bu yap\u0131lar, optik sinir, k\u00f6r nokta ve sar\u0131 benektir. Retina taraf\u0131ndan i\u015flenen \u0131\u015f\u0131k \u0131\u015f\u0131nlar\u0131na dair bilgiler, beyinde g\u00f6r\u00fcnt\u00fcn\u00fcn olu\u015fumunu sa\u011flamak i\u00e7in optik sinire y\u00f6nlendirilir. Optik sinir, duyu n\u00f6ronlar\u0131n\u0131n akson b\u00f6lgelerinin g\u00f6z\u00fcn arkas\u0131nda bir noktada bir araya gelmesiyle olu\u015fturduklar\u0131 temel sinir a\u011f\u0131 yap\u0131s\u0131d\u0131r. Bu noktada, yani bu birle\u015fimin ger\u00e7ekle\u015fti\u011fi noktada fotoresept\u00f6rler yer almaz, dolay\u0131s\u0131yla \u0131\u015f\u0131\u011f\u0131n i\u015flenmesine ili\u015fkin herhangi bir i\u015flem bu b\u00f6lgede ger\u00e7ekle\u015fmez. Bu nedenle bu b\u00f6lgeye k\u00f6r nokta ad\u0131 verilir.<\/p>\n

G\u00f6r\u00fc\u015f nas\u0131l ger\u00e7ekle\u015fir?
\n<\/strong>Tabakalar\u0131 a\u00e7\u0131klarken a\u00e7\u0131k bir bi\u00e7imde ifade edildi\u011fi \u00fczere g\u00f6rme olay\u0131nda \u00f6nemli noktalar \u0131\u015f\u0131\u011f\u0131n alg\u0131lanmas\u0131, \u0131\u015f\u0131\u011f\u0131n odaklanmas\u0131 ve \u0131\u015f\u0131\u011fa dair bilgilerin i\u015flenerek beyne iletilmesidir. Bu noktalar\u0131 yeniden vurgulayarak g\u00f6rme olay\u0131na dair bir \u00f6zet yapacak olursak, \u0131\u015f\u0131k ilk olarak korneadan ge\u00e7er. Korneada g\u00f6z merce\u011fi hedeflenecek \u015fekilde b\u00fck\u00fclen \u0131\u015f\u0131k \u0131\u015f\u0131nlar\u0131 \u00f6ncelikle iris taraf\u0131ndan alg\u0131lan\u0131r. \u0130ris, g\u00f6ze gelen \u0131\u015f\u0131k \u0131\u015f\u0131nlar\u0131n\u0131n miktar\u0131na g\u00f6re g\u00f6z bebe\u011fini ayarlar ve g\u00f6z i\u00e7erisinde i\u015flenecek \u0131\u015f\u0131k miktar\u0131n\u0131 d\u00fczenler. G\u00f6zbebe\u011finden ge\u00e7erek g\u00f6z merce\u011fine gelen \u0131\u015f\u0131k \u0131\u015f\u0131nlar\u0131 burada k\u0131r\u0131n\u0131ma u\u011frar. G\u00f6z merce\u011fi, \u0131\u015f\u0131k \u0131\u015f\u0131nlar\u0131n\u0131 retinaya odaklar. Retinada bulunan fotoresept\u00f6rler taraf\u0131ndan fark edilen \u0131\u015f\u0131k \u0131\u015f\u0131nlar\u0131na dair bilgiler bu resept\u00f6rler taraf\u0131ndan \u00f6\u011frenilir. Bu bilgiler retina taraf\u0131ndan i\u015flenerek g\u00f6z\u00fcn arka k\u0131sm\u0131nda bulunan optik sinirlere aktar\u0131l\u0131r. Optik sinirler yoluyla g\u00f6z\u00fcm\u00fcze g\u00f6nderilen g\u00f6rselin g\u00f6r\u00fcnt\u00fcs\u00fc beyinde olu\u015fmu\u015f olur.<\/p>\n

Kaynak:<\/strong> https:\/\/nei.nih.gov\/health\/cornealdisease
\nhttps:\/\/www.allaboutvision.com\/resources\/sclera.htm
\nhttps:\/\/www.healthline.com\/human-body-maps\/iris-eye#1
\nhttps:\/\/www.healthline.com\/human-body-maps\/retina<\/p>\n","protected":false},"excerpt":{"rendered":"

\u00c7evremizi duyular\u0131m\u0131z yoluyla alg\u0131l\u0131yoruz. Bu nedenle duyular\u0131m\u0131z\u0131 olu\u015fturan veya bir duyunun olu\u015fumuna yard\u0131mc\u0131 olan organlar\u0131n \u00e7ok \u00f6nemli i\u015flevleri var. Bu organlar temel i\u015flevlerini yerine getirerek g\u00f6rmemizi, i\u015fitmemizi, koku almam\u0131z\u0131, tat almam\u0131z\u0131 ve nesneleri hissetmemizi sa\u011fl\u0131yor. Peki, bu yap\u0131lar nas\u0131l i\u015fliyor, hangi mekanizmalar yoluyla i\u015flevlerini yerine getirebiliyor? \u0130lk olarak g\u00f6rme organ\u0131 olan g\u00f6z ve g\u00f6rme olay\u0131 […]<\/p>\n","protected":false},"author":1390,"featured_media":36520,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[19],"tags":[254,5269,1578,1986,3355,788],"class_list":["post-36519","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-bilim-gundemi","tag-beyin","tag-duyu","tag-gorme","tag-goz","tag-kornea","tag-retina"],"acf":[],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t