Ingqungquthela ye-thyroid iyilungu elinjenge-butterfly, elingaba ngu-2 intshi ububanzi kwaye lilinganisa i-10 ukuya kwe-20 amagremu, ephantsi kwentamo phambi kwe- trachea (i-windpipe). Umsebenzi wayo ukwenza ihomoni ezibaluleke kakhulu kwi-body's metabolism kunye neminye imisebenzi ebalulekileyo.
Iimodmoni ezimbini ezinkulu ezikhutshwa yi-thyroid gland-thyroxine (T4) kunye ne-triiodothyronine (T3) -ncedisa ukulawula, phakathi kwezinye izinto, ukulinganisa intliziyo, ubunzima bomzimba, amandla omzimba, ukuphefumla, ukushisa komzimba, amaqondo e-blood lipid, ukuhamba kwimizi, inkqubo yeentambo, kunye nenkcitho yamandla.
Kwiintsana, i-hormone ye-thyroid ibalulekile ekuphuhlisweni kwengqondo kunye nesistim somzimba. Ngoko, isifo se-thyroid esebenza ngokuqhelekileyo kubaluleke kakhulu ekuphuculweni kwezinto eziqhelekileyo kubantwana, nakubomi bobudala bexesha elide kunye nomzuzu.
Into eyenziwa yiGirl Gland
Ingumsebenzi we-thyroid gland ukuvelisa i-hormone ye-thyroid, i-T3 kunye ne-T4. Impawu ezahlukileyo ze-hormone ye-thyroid kukuba ziqukethe i-atom ye-iodine-T3 inee-athomu ze-iodine ezintathu, kwaye i-T4 inezine. Ngenxa yoko, i-thyroid gland iyingqayizivele kwikhono layo elikhethekileyo lokuthatha iodine ukusuka kwigazi, ukuze lifakwe kwi-hormone ye-thyroid.
Zonke i-T4 emzimbeni ziveliswa yi-thyroid gland-malunga ne-80 ukuya kwi-100 mcg ngosuku. Amaxesha angama-10 loo mali ye-T4 (malunga ne-1000 mcg) iyajikeleza egazini. Ngaphezu kweepesenti ezingama-99 ze-T4 ezijikelezayo zibophelelwe iiprotheni kwi-plasma (ngokukodwa, kwi-glog-binding globulin, TBG).
Kuphela inxalenye encinane yokujikeleza i-T4 engabonakaliyo ("inkululeko" T4) ifumaneka ukusetyenziswa.
Phantse iipesenti ezili-10 ze-T4 ezijikelezayo (ezilinganayo nomlinganiselo we-T4 entsha ekhishwe imihla ngemihla nge-thyroid gland) ihlaziywa ngalunye usuku. Ngokuqhelekileyo, malunga nesiqingatha sale mali liguqulwa kwi T3 (ngokucima enye yee-athomu ze-iodine), kwaye intsalela iguqulwa ukuba " iguqule i-T3 " (rT3, ngokucima i-atom ye-iodine kwindawo ehlukile).
I-T3 yi-hormone esebenzayo ye-thyroid, ngelixa i-rT3 ingasebenzi ngokupheleleyo.
Iipesenti ezingama-20 kuphela ze-T3 emzimbeni ziveliswa yi-thyroid gland. Amanye ama-80 ekhulwini aveliswa yi-T4 ngaphakathi kwimizimba-ingakumbi ngeentso, isibindi, isisu, ingqondo, isikhumba kunye ne-placenta. Imveliso epheleleyo yeT3 ngosuku i malunga ne-30-40 mcg, kwaye ininzi ye-T3 ngaphandle kwe-thyroid gland iphakathi kweeseli zomzimba. I-T3 ihlaziywa ngokukhawuleza ngakumbi kuneT4.
Indlela efanelekileyo yokujonga i-hormone ye-thyroid kukuqwalasela i-T4 ibe "i-pro-hormone" ye-T3-oko kukuthi, ukucinga nge-T4 njengoko kuqukethe idibanti elikhulu "elingenako" iT3. Isixa esifanelekileyo se-T4 siguqulwa ngexesha elifanelekileyo kwi-T3, ngokwemiqathango yomzimba ngemizuzu emfutshane. I-T3 ke yenza umsebenzi. Ukuthintela ukuqokelelwa kakhulu kwe-T4, "ukugqithisa" i-T4 iguqulwa ibe yintsebenziswano ye-TT3, echithwe ngamathambo.
Into eyenziwa yi-Thyroid Hormones
Ngokomxholo, i-hormone ye-thyroid-ngokukodwa, i-T3-ilawula ngokuthe ngqo ukuveliswa kweeprotheni ezahlukahlukeneyo ezenziwe ngamaseli omzimba. I-T3 yenza oku ngokubopha kwi-DNA yeseli.
I-T4 yamahhala kunye ne-T3 yamahhala ejikelezayo egazini ifumaneka ngokukhawuleza ukungena kwiiseli zomzimba xa zifuneka.
Ezinye ze-T4 ze-intracellular ziguqulwa zibe yi-T3, kwaye ezinye ze-T3 zibopha kwi-T3-receptors ezithile kwi-nucleus yeseli. Oku kubanjwe i-T3 kubangela ukuba i-DNA yenyukliya ivuse (okanye ikhuphe) ukuveliswa kweeprotheni ezithile.
Amaseli ahlukeneyo emzimbeni aneentlobo ezahlukeneyo ze-T3-receptors zenyukliya, kwaye kwiindawo ezihlukeneyo, ngoko umphumo we-T3 kwiseli iyashintsha ngokubanzi ukusuka kwinyama ukuya kwiimpawu, kwaye phantsi kweemeko ezahlukeneyo. Nangona kunjalo, kuzo zonke iimeko ze-hormone ze-thyroid zisebenza ngokulawula umsebenzi we-DNA, okwenza ukwandise okanye ukunciphisa imveliso yamaprotheni abalulekileyo.
Phakathi kwezi proteins zi-enzymes ezahlukahlukeneyo, ezilawula ukuziphatha kwemisebenzi eminingi ebalulekileyo yomzimba.
Indlela i-Thyroid System elawulwa ngayo
Njengoko sibonile, i-hormones ye-thyroid ibaluleke kakhulu kwixesha elide kunye neyokulawula imizuzu emininzi yemizuzu emininzi yomzimba. Naliphi na ixesha inkqubo yokuphila yinto ebalulekileyo, siza kubona ukuba uluntu lunikeze iindawo eziqingqiweyo zomgaqo-nkqubo, ezijolise ekuqinisekiseni ukuba le nkqubo isetyenziswe ngokufanelekileyo ukwenza oko kufuneka ukuyenza, kwaye ukuba umsebenzi wayo ulawulwa kwinqanaba elincinci. Ezi zigaba eziyinkimbinkimbi zolawulo olusebenzayo ngokuqinisekileyo ziyasebenza kwinkqubo ye-thyroid.
Makhe sijonge ngokukhawuleza kwi "ezinkulu" zomgaqo we-thyroid.
I-Pituitary-Thyroid Axis. I-axis-thyroid axis inikeza ulawulo oluphezulu kwi-thyroid gland ngokwayo. I-pituitary gland (i-gland ephantsi ngaphakathi kwengqondo) ikhupha i-TSH, okanye i-thyroid eyenza i-hormone. I-TSH ibangela i-thyroid gland ukuba yandise umveliso wayo kunye nokukhutshwa kwe-T3 kunye ne-T4. Ngexesha elifanayo, ukujikeleza i-hormone ye-thyroid (ngokukodwa, i-T3) inqanda ukuveliswa kwe-TSH nge-pituitary, ngaloo ndlela yenza i-loop negative feedback. Ngoko, njengoko izinga legazi leT3 landa, amazinga e-TSH awela. Le loop yengxelo isebenzayo ukugcina imveliso ye-hormone ye-thyroid nge-thyroid gland ngaphakathi kwindlela elula.
I-Hypothalamus-Pituitary Axis. Ukukhutshwa kwe-TSH nge-pituitary gland, ngaphezu kokuphendula ukujikeleza i-T3, kulandelelaniswa nokukhutshwa kwe-TRH (i-thyrotropin-release hormone) yi-hypothalamus. Ukukhululwa kwe-TRH yi-hypothalamus kubangela ukuba i-pituitary gland ikhuphe i-TSH ngaphezulu, kwaye ngaloo ndlela, yandisa imveliso ye-hormone ye-thyroid nge-thyroid gland.
I-hypothalamus yinxalenye yokuqala yengqondo edibanisa imisebenzi emininzi yomzimba, njengemigangatho ye-circumcadian, inkqubo ye-neuroendocrine, inkqubo ye-nervous system, kunye nabanye abaninzi. I-hypothalamus isabela kwizinto ezininzi ezibandakanya ukukhanya kunye nomnyama, ukuvumba, ithoni yokuzimela, amahomoni amaninzi, uxinzelelo lwengqondo, kunye nemigudu ye-neural evela entliziyweni nasemathunjini.
I-hormone yemveliso ye-thyroid ayixhomekeke kuphela kwi-TSH, kodwa ixhomekeke kwinto leyo i-hypothalamus "yokucinga nokuvakalelwa" malunga nemeko yonke yomzimba kunye nendalo.
Iiprotheni Ukukhupha amaHormone e-Thyroid. Njengoko kubonisiwe, ngaphezu kwe-99% yehomoni ye-thyroid ekuhanjisweni ibophelelwe kwiiprotheni egazini, ngokubhekiselele kwi-TBG. Ngaphezulu, i-hormone ye-thyroid ene-protein ayisebenzi. I-T4 kuphela kunye ne-T3 banomsebenzi owenzela umzimba.
Le prothini ebophekayo ye-hormone ye-thyroid isebenza imisebenzi emininzi yokulawula. Inika umthombo omkhulu wokujikeleza i-T4 ukukhusela ekunciphiseni ngokukhawuleza kwimisebenzi ye-thyroid gland, ngelixa ugcina iingcamango ezikhulu ze-T3 kunye ne-T4 kwimida emincinci.
Ukuba le nkunkuma yeT4 ayifumanekanga, izicubu ziya kubanjelwa i-hormone ye-thyroid kwiiyure ezimbalwa, ukuba isifo se-thyroid sasinokuba sesikhashana.
Iprotheni ebopha i-hormone ye-thyroid iyakhusela nakuphi ukwanda ngokukhawuleza kokujikeleza i-T3 yamahhala, ukuba ama-tissu anokunyusa ngokukhawuleza ukuguqulwa kwawo kwe-T4 ukuya kwi-T3.
Umthamo we-intracellular yeHormone Hormones . Njengoko sibonile, i-T3 ne-T4 yenza umsebenzi wabo obalulekileyo ngaphakathi kweeseli. Ukusebenza kwabo ngokuqhelekileyo ngaphakathi kweeseli-kubandakanywa ukuthutha kwi-membrane yeseli ukusuka egazini ukuya ngaphakathi kweeseli, ukuguqulwa kweT4 ukuya kwi-T3, ukuwela kweT3 kwi-cell cell, kunye nokubopha kwe-T3 kwi-DNA-kuxhomekeka ininzi yeeprotheni zokulawula kunye nezothutho ngaphakathi kweeseli ezibonakalayo kunye nempawu.
Isishwankathelo . I-thyroid inkqubo ilawulwa kumanqanaba amaninzi. Ummiselo omkhulu ufezekiswa nge-axis-thyroid axis, leyo (nge-modulation ehlinzekwa yi-hypothalamus ukuba ingqalelo ukuhlolwa jikelele kweemfuno zomzimba jikelele), inquma indlela i-hormone ye-thyroid eyenziwa ngayo i-thyroid gland ivelisa kwaye ikhutshwe. Amanqanaba e-hormone ye-thyroid ehamba ngokukhululekile efumaneka kwiimfucu zixutywa, nge-minute-to-minute, nge-TBG kunye nezinye iiprotheni zegazi ezibophezelayo. Kwaye, ngokukhawuleza, i-T3-ye-nuclear-receptors, i-DNA yeseli, iyabonakala ilawulwa yiiprotheni ezininzi ze-intracellular. Le nkqubo yokumisela iqinisekisa ukuba i-hormone ye-thyroid inokufumaneka ngamaxesha onke kwiifom, kodwa ngexesha elifanayo livumela ukulawulwa kakuhle kakhulu kwe-thyroid-DNA interface phakathi kweeseli nganye.
Iingxaki zeTyroid
Yiyo yonke imimiselo yomgaqo, kumanqanaba amaninzi. Kwaye kuthetha ukuba izifo ze-thyroid zingenzeka ngezifo ezichaphazela i-thyroid gland ngokwayo, okanye ngeemeko ezichaphazela i-hypothalamus, i-pituitary, okanye iiprotheni zegazi, okanye nokuba neengxaki ezichaphazela ukuphathwa kwee-hormone ze-thyroid ngamathambo ahlukeneyo omzimba.
Ngokuqhelekileyo, ukuphazamiseka kwenkqubo ye-thyroid kubangela ukuba umsebenzi we -roid usebenze kakubi ( hypothyroid ), okanye ungasebenzi ( hyperthyroid ). Ukongeza kwezi ngxaki eziqhelekileyo, i-thyroid gland ingaba yanda kakhulu (imeko ebizwa ngokuba yi- goiter ). I-cancer ye-thyroid gland ibonakala. Naliphi na le miqathango inokubaluleka kakhulu.
Iimpawu zesifo se-thyroid ziyahlukahluka. Iimpawu ze-hypothyroidism zihlala ziquka isikhumba esomileyo, isantya sentliziyo, isilumko, ukukhwabanisa, utshintsho lwesikhumba, ukulahleka kweenwele, ukunyaniseka, ukufumana ubunzima, kunye nabanye abaninzi. Iimpawu eziqhelekileyo ze-hyperthyroidism ziquka i-pulse ephakamileyo, amehlo anomileyo, ubuhlungu obunokukhanya, ukungabonakali, ukunqunyulwa kweenwele, ubuthathaka kunye nokuthuthumela-kodwa kwakhona kukho nezinye iimpawu ezininzi ezinokubonakala. Funda kabanzi malunga neempawu zesifo se-thyroid .
Ukuchonga ingxaki ye-thyroid kufuna ukuhlalutya ngokucokisekileyo ukuhlola i-thyroid yegazi, kunye nokuvavanywa okongeziweyo ukuba unobungozi be -roid. Funda malunga nokuhlolwa kwe-thyroid .
Xa ufumanisa ingxaki ye-thyroid, ukuvavanya i-pituitary-thyroid axis ibaluleke kakhulu. Oku kungenziwa ngokubanzi ngokulinganisa i-serum yamahhala T3 kunye ne-T4, kunye namanqanaba e-TSH ye-serum. Ukuba amazinga e-TSH aphakanyisiwe, kubonisa ukuba i-thyroid gland ayivelisi i-hormone eyaneleyo, kwaye i-pituitary izama ukubetha umsebenzi wayo. Ukuba amazinga e-TSH ayacinywa, kusenokuthetha ukuba i-thyroid gland ivelisa i-hormone ephezulu ye-thyroid.
Kwezinye iimeko, ukutolika ngokufanelekileyo kwamanqanaba e-TSH kunokukhohlisa, kwaye ngokuqinisekileyo kuya kuba nengxabano. Funda kabanzi malunga nokuhlolwa kweTSH kunye nokutolika .
Ukunyanga okuthe ngqo kwezifo ze-thyroid kungakhohlisa, kodwa ngokuqhelekileyo ingxaki ibilisa ukukhetha phakathi kweendlela ezahlukeneyo zonyango, kunokufuna unyango olusebenzayo nonke. Funda malunga nenye ingxabano ngokuphathelele unyango lwe-hypothyroidism , kunye ne- hyperthyroidism .
ILizwi
I-thyroid gland, kwaye i-hormone evelisa, ibaluleke kakhulu ekuphuculweni komntu kunye nokuphila okunempilo. Ubume obubalulekileyo bomsebenzi we-thyroid bubonakala kwiindlela eziyinkimbinkimbi ezenziwe ngumgangatho we-hormone ye-thyroid. Ngenxa yokuba inkqubo ye-thyroid ibaluleke kakhulu, kubalulekile ukuxilonga ngokufanelekileyo kwaye uphathwe nayiphi na ingxaki ye-thyroid.
> Imithombo:
> Brent GA. Iinkqubo zeTyroid Hormone Action. J Clin Invest 2012; 122: 3035.
> Jonklaas J, Bianco AC, uBauer AJ, et al. Izikhokelo zoLonyango lwe-Hypothyroidism: Lulungiswe nguMbutho we-American Thyroid Association Task Force kwi-Hormone Replacement. Thyroid 2014; 24: 1670.
> Mullur R, Liu YY, Brent GA. I-Hormone Regulation of Metabolism. Physiol Rev 2014; 94: 355.
> Ross DS, Burch HB, Cooper DS, et al. 2016 Izikhokelo ze-American Thyroid Association Guidelines for Diagnosis and Management of Hyperthyroidism kunye nezinye izizathu ze Thyrotoxicosis. Thyroid 2016; 26: 1343.