I-gland yegciwane iyilungu elinjenge-butterfly, elingaba ngamasentimitha amabili ububanzi futhi linesisindo esingama-gramu ayi-10 kuya kwangu-20, esisekelweni lentamo phambi kwe- trachea (i-windpipe). Umsebenzi walo ukwenza ama-hormone abaluleke kakhulu ekusebenzeni komzimba kanye neminye imisebenzi ebalulekile.
I-hormone ezimbili ezinkulu ezikhishwa yi-gland-thyroxine (T4) kanye ne-triiodothyronine (T3) -ukusiza ukulawula, phakathi kwezinye izinto, izinga lokushaya kwenhliziyo, isisindo somzimba, amandla omzimba, ukuphefumula, izinga lokushisa komzimba, amazinga e-blood lipid, imijikelezo yokuya esikhathini, isimiso sezinzwa, kanye nezindleko zamandla.
Ezinganeni, ama-hormone wegciwane abalulekile ekuthuthukiseni ubuchopho kanye nesistimu yamathambo. Ngakho-ke, i-gland yegciwane esebenza ngokujwayelekile ibalulekile ekuthuthukiseni okuvamile kwezingane, futhi kokubili inhlalakahle yesikhathi eside neyomzuzu.
Okushiwo yi-Gland Gland
Kungumsebenzi we-gland wegciwane ukukhiqiza ama-hormone wegciwane, i-T3 ne-T4. Isici esihlukanisayo se-hormone yegciwane ukuthi iqukethe ama-athomu e-iodine-T3 ineama-athomu amathathu e-iodine, kanti i-T4 inezine. Ngakho-ke, igulane le-thyroid liyingqayizivele ekhono layo elikhethekile lokuthatha i-iodine egazini, ukuze lifakwe kumahomoni wegciwane.
Yonke i-T4 emzimbeni ikhiqizwa ngendlala ye-thyroid-cishe ngo-80 kuya ku-100 mcg ngosuku. Cishe izikhathi ezingu-10 leyo mali ye-T4 (cishe i-1000 mcg) ijikeleza egazini. Amaphesenti angaphezu kwamaphesenti angu-99 we-T4 ejikelezayo aphethwe amaprotheni eplasma (ikakhulukazi, kwi-gyroid-binding globulin, TBG).
Ingxenye encane kuphela ye-T4 ejikelezayo engabonakali ("mahhala" T4) iyatholakala ukuze isetshenziswe.
Amaphesenti angaba ngu-10 e-T4 ejikelezayo (okulingana nenani le-T4 elisha elikhishwe nsuku zonke nge-gland yegciwane) lihlaziywa usuku ngalunye. Ngokuvamile, cishe ingxenye yesigamu sale mali ishintshelwe ku-T3 (ngokunqamula enye ye-athomu ye-iodine), futhi okusele kuguqulwa " ukuguqula i-T3 " (rT3, ngokunqamula i-athomu le-iodine endaweni ehlukile).
I-T3 i-hormone ye-thyroid esebenzayo, kuyilapho i-rT3 ingasebenzi ngokuphelele.
Amaphesenti angaba ngu-20 kuphela e-T3 emzimbeni akhiqizwa ngendlala yegciwane. Amanye amaphesenti angu-80 akhiqizwa yi-T4 ngaphakathi kwezicubu-ikakhulukazi izinso, isibindi, imisipha, ubuchopho, isikhumba, kanye ne-placenta. Ukukhiqizwa okuphelele kwe-T3 ngosuku kungaba ngu-30-40 mcg, kanti iningi le-T3 ngaphandle kwegciwane le-thyroid likhona ngaphakathi kwamaseli omzimba. I-T3 ihlaziywa ngokusheshisa kakhulu kune-T4.
Indlela ewusizo yokubheka ama-hormone wegciwane ukucubungula i-T4 ibe "i-pro-hormone" ye-T3-okuwukuthi, ucabange ngo-T4 njengokuthi kuqukethe i-pool elikhulu "yekhono" le-T3. Inani elilinganayo le-T4 liguqulwa ngesikhathi esifanele ku-T3, ngokusho kwemizuzu yomzuzu kuya kwemizuzu yomzimba. I-T3 yabe isenza umsebenzi. Ukuvimbela ukuqoqwa kokuhamba okuningi kwe-T4, "ukudlula" i-T4 kuguqulwa ibe yi-rT3 engasebenzi, ehlanganiswa izicubu.
Lokho amaHormone e-Thyroid empeleni enza
Ngokuyisisekelo, ama-hormone wegciwane-ngokuqondile, i-T3-ilawula ngokuqondile ukukhiqizwa kwamaprotheni ahlukahlukene eyenziwe ngamaseli omzimba. I-T3 yenza lokhu ngokubophezela ku-DNA yeselula.
I-T4 yamahhala kanye ne-T3 yamahhala ejikeleza egazini iyatholakala ukuze ufake ngokushesha amangqamuzana omzimba noma kunesidingo.
Ezinye ze-T4 ze-intracellular ziguqulwa zibe yi-T3, kanti ezinye ze-T3 zibopha kuma-T3-receptors athile ku-nucleus yeseli. Lokhu kuhlanganiswa kwe-T3 kubangela ukuthi i-DNA yenyukliya ivuse (noma ivimbele) ukukhiqizwa kwamaprotheni athile.
Amaseli ahlukene emzimbeni anezinhlobo ezahlukene ze-T3-nuclear receptors, futhi ezindaweni ezihlukahlukene, ngakho-ke umphumela we-T3 esitokisini uguquke kakhulu kusuka kumzimba kuya kwezicubu, futhi ngaphansi kwezimo ezihlukahlukene. Kodwa-ke, kuzo zonke izimo amahomoni e-thyroid enza ngokulawula umsebenzi we-DNA, okwenza ukwandise noma ukunciphisa ukukhiqizwa kwamaprotheni aqakathekileko.
Phakathi kwala maprotheni kukhona ama-enzyme ahlukahlukene, abuye alawula ukuziphatha kwemisebenzi eminingi ebalulekile yomzimba.
Indlela uhlelo lwe-Thyroid olulawulwa ngayo
Njengoba sibonile, ama-hormone e-thyroid asemqoka kokubili kokulawula isikhathi eside nokulawula imizuzu eminengi ngemisebenzi ebalulekile yomzimba. Noma yisiphi isikhathi isistimu yezinto eziphilayo kubaluleke kangaka, sizobona ukuthi imvelo inikeze izingxenye eziyinkimbinkimbi zomthethonqubo, okuhloswe ukuqinisekisa ukuthi uhlelo luhlelwe kahle ukwenza lokho okudingeka luyenze, nokuthi umsebenzi walo ulawulwa ngaphakathi kwebala elincane. Lezi zingxenye eziyinkimbinkimbi zokulawula okuphezulu zisebenza ngokuqondile ohlelweni lwe-thyroid.
Ake sibheke kancane "izingqimba" ezinkulu zomthethonqubo wegciwane.
I-Pituitary-Thyroid Axis. Isikhwama se-pituitary-thyroid sinikeza ukulawula okuyinhloko phezu kwegciwane le-thyroid ngokwayo. I-pituitary gland (i-gland ehlala ngaphakathi ngaphakathi kobuchopho) ikhulula i-TSH, noma i-hormone evuselela i-thyroid. I-TSH ibangela ukuthi igciwane le-thyroid likhulise ukukhiqizwa kwalo nokukhululwa kwe-T3 no-T4. Ngesikhathi esifanayo, ukujikeleza i-hormone ye-thyroid (ngokuqondile, i-T3) igwema ukukhiqizwa kwe-TSH yi-pituitary, ngaleyo ndlela yakha i-loop negative feedback. Ngakho, njengoba amazinga egazi le-T3 ekhuphuka, amazinga e-TSH awela. Le loop yokuphendula isebenza ukugcina ukukhiqizwa kwehomoni yegciwane ngenduku ye-thyroid ngaphakathi kwezingcingo ezincane.
I-Hypothalamus-Pituitary Axis. Ukukhululwa kwe-TSH nge-pituitary gland, ngaphezu kokuphendula ukujikeleza kwe-T3, kubuye kulungiselelwe ukukhululwa kwe-TRH (thyrotropin-release release hormone) yi-hypothalamus. Ukukhululwa kwe-TRH yi-hypothalamus kwenza i-pituitary gland ikhiphe ngaphezulu kwe-TSH, futhi ngaleyo ndlela, yandisa ukukhiqizwa kwe-hormone ye-thyroid nge-gland yegciwane.
I-hypothalamus yingxenye eyinhloko yobuchopho eqondisa imisebenzi eminingi eyisisekelo yomzimba, njengemigqi ye-circadian, uhlelo lwe-neuroendocrine, isimiso sezinzwa sokuzimela, kanye nabanye abaningana. I-hypothalamus isabela ezintweni eziningi ezibandakanya ukukhanya nokumnyama, iphunga, ithoni yokuzimela, amahomoni amaningana, ukucindezeleka ngokomzwelo, kanye nemibono ye-neural evela enhliziyweni nasegulini.
Ngakho ukukhiqizwa kwe-hormone ye-thyroid akuxhomeke kuphela ku-TSH, kodwa futhi kuxhomeke kulokho i-hypothalamus "yokucabanga nokuzwa" ngesimo sonke somzimba kanye nemvelo.
Amaprotheni Ukubopha amaHormone e-Thyroid. Njengoba kukhonjisiwe, i-hormone ye-thyroid engaphezu kwe-99 ehamba phambili ihambisana namaprotheni egazini, ikakhulukazi ku-TBG. Ngaphezu kwalokho, i-hormone ye-thyroid eboshelwe amaprotheni ayisebenzi. I-T4 kuphela ne-T3 kuphela enomsebenzi we-physiologic.
Le phrotheni ebopha amahomoni e-thyroid isebenza imisebenzi eminingana ebalulekile yokulawula. Ihlinzeka igumbi elikhulu lokujikeleza i-T4 ukuvikela ngokunciphisa ngokungazelelwe umsebenzi wegciwane le-thyroid, ngenkathi kugcinwa ukugxila okukhululekile kwe-T3 no-T4 mahhala ngaphakathi kwemingcele emincane kakhulu.
Uma lesi sitsha se-T4 singatholakali, ama-tissue ayengeke avunywe i-hormone ye-thyroid esikhathini esingaphansi kwamahora ambalwa, uma isikhumba se-thyroid sizoba sesikhashana.
Iprotheyini ebopha amahomoni we-thyroid ivikela nanoma yikuphi ukukhushulwa okungazelelwe kokujikeleza i-T3 yamahhala, uma izicubu zandisa ngokushesha ukuguqulwa kwazo kwe-T4 kuya ku-T3.
Ukulawulwa kwe-intracellular ye-Hormone ye-Thyroid . Njengoba sibonile, i-T3 no-T4 benza umsebenzi wabo obalulekile ngaphakathi kwamaseli. Ukusebenza kwabo okuvamile ngaphakathi kwamaseli-kuhlanganise nokuthutha kwabo kulo lonke i-membrane yeseli kusuka egazini ukuya ngaphakathi kwangaphakathi kwamaseli, ukuguqulwa kwe-T4 kuya ku-T3, ukuwela kwe-T3 kwinombolo ye-cell, kanye nokubopha kwe-T3 kuya ku-DNA-kuxhomeke ku- inqwaba yamaprotheni okulawula kanye nokuthutha ngaphakathi kwamaseli ayenziwa ukuthi izimpawu nezici zikhona.
Isifingqo . Uhlelo lwe-thyroid lulawulwa emazingeni amaningi. Umthethonqubo omkhulu kakhulu utholakala nge-axis-thyroid axis (okuyinto (nge-modulation ehlinzekwa yi-hypothalamus ukucabangela ukuhlolwa okujwayelekile kwezidingo zomzimba jikelele), inquma ukuthi i-hormone ye-thyroid ikhiqizwa kanjani futhi ikhishwa. Amazinga okuhamba mahhala amahomoni e-thyroid etholakalayo ama-tissue aphikisiwe, ngesisekelo esisodwa ngomzuzu, yi-TBG kanye nezinye iziprotheyini zegazi ezibopha i-thyroid. Futhi, ngesikhathi esisodwa, ukubophezelwa kwangempela kwe-T3 kuya ku-T3-nuclear receptors, esakhiweni se-DNA yeselula, kubonakala sengathi kulawulwa amaprotheni amaningi angaphakathi. Lesi simiso somthetho siqinisekisa ukuthi i-hormone eminingi ye-thyroid iyatholakala ngezikhathi zonke ngezicubu, kepha ngesikhathi esifanayo ivumela ukulawulwa kahle kakhulu kwe-thyroid-DNA interface ngaphakathi kwamangqamuzana ngabanye.
Izinkinga ze-Thyroid
Lokho kungumthetho omkhulu, kuwo wonke amazinga amaningi. Futhi kusho ukuthi izifo ze-thyroid zingenzeka ngezifo ezithinta igciwane le-thyroid ngokwayo, noma ngezimo ezithinta i-hypothalamus, i-pituitary, noma amaprotheni wegazi, noma ngisho neziphazamiso ezithinta ukuphathwa kwamahomoni wegciwane ngamathambo ahlukahlukene omzimba.
Ngokuvamile, ukuphazamiseka kwesimiso se-thyroid kuvame ukubangela umsebenzi we -roid ukuthi ube ongasebenzi ( hypothyroid ), noma ongasebenzi ngokweqile ( hyperthyroid ). Ngaphandle kwalezi zinkinga jikelele, ingubo ye-thyroid ingaba yande kakhulu (isimo esibizwa ngokuthi i- goiter ). I-Cancer ye- gland yegciwane ibonakala. Noma yikuphi kulezi zimo kungase kube nzima kakhulu.
Izimpawu zesifo se-thyroid zingashintsha kakhulu. Izimpawu ze-hypothyroidism ngokuvamile zihlanganisa isikhumba esomile, isilinganiso senhliziyo esinciphile, ukuvilapha, ukukhukhumeza, izinguquko zesikhumba, ukulahlekelwa izinwele, ukuzithemba, ukuzuza kwesisindo, nabanye abaningi. Izimpawu ezijwayelekile ze-hyperthyroidism zihlanganisa ukushayela okuphakeme, amehlo anomile, ukuzwela ukukhanya, ukuleleka, ukunqanda izinwele, ubuthakathaka nokuthuthumela - kodwa futhi kukhona nezinye izimpawu eziningi ezingabonakala. Funda kabanzi mayelana nezimpawu zesifo se-thyroid .
Ukuqaphela inkinga ye -roid kudinga ukuhlaziywa ngokucophelela kokuhlola ukuhlolwa kwegazi le-thyroid, nokuhlolwa okungeziwe uma isimo se -roid sikholelwa. Funda mayelana nokuhlolwa kwe-thyroid .
Ekuhloleni isifo se-thyroid, ukuhlola i-aisis ye-pituitary-thyroid kubaluleke kakhulu. Lokhu kungenziwa ngokuvamile ngokulinganisa i-serum yamahhala T3 no-T4, namazinga we-TSH we-serum. Uma amazinga e-TSH ephakanyisiwe, kubonisa ukuthi i-gland yegciwane ayikhiqizi i-hormone eyanele, kanti i-pituitary izama ukushaya isenzo sayo. Uma amazinga e-TSH enqanyuliwe, kungase kusho ukuthi igciwane le-thyroid likhiqiza amahomoni amaningi kakhulu wegciwane.
Kwezinye izimo, ukuchazwa okufanele kwamazinga e-TSH kungaba okukhohlisayo, futhi ngokuqinisekile kungaba impikiswano. Funda kabanzi mayelana nokuhlolwa kwe-TSH nokuchazwa .
Ukuphathwa kahle kwesifo se-thyroid kungase kube buqili, kodwa ngokuvamile inkinga ibhebhezela ekukhethweni phakathi kwezinqubo ezihlukahlukene zokwelapha, kunokufuna ukwelashwa okusebenza nhlobo. Funda mayelana nokuphikisana okuphathelene nokuphathwa kwe-hypothyroidism , kanye ne- hyperthyroidism .
Izwi elivela
I-gland yegciwane, namahomoni akhiqiza, kubaluleke kakhulu ekuthuthukiseni abantu nasekuphileni okuphilile. Ukubaluleka komsebenzi we-thyroid kubonakala ezindleleni eziyinkimbinkimbi lapho imvelo isungulwe ukulawulwa kwamahomoni wegciwane. Ngenxa yokuthi uhlelo lwe-thyroid lubaluleke kakhulu, kubalulekile ukuxilonga kahle nokuphatha noma yikuphi ukuphazamiseka kwe-thyroid.
> Imithombo:
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> Jonklaas J, Bianco AC, uBauer AJ, et al. Imihlahlandlela yokwelashwa kwe-Hypothyroidism: Yilungiselelwe i-American Thyroid Association Task Force kwi-Thyroid Hormone Replacement. I-Thyroid 2014; 24: 1670.
> Mullur R, Liu YY, Brent GA. I-Hormone ye-Thyroid Ukulawulwa Kwemetabolism. I-Physiol Rev 2014; 94: 355.
> Ross DS, Burch HB, Cooper DS, et al. I-2016 American American Association Association Imihlahlandlela Yokuqapha Nokuphathwa Kwe-Hyperthyroidism Nezinye Izimbangela Ze-Thyrotoxicosis. I-Thyroid 2016; 26: 1343.