Thyroid wata ƙaramar gland ce mai siffar malam buɗe-mana a gaban wuya, ƙasa da ƙullin maƙogwaro (Adam's apple). Tana samar da sinadaran hormone guda biyu, T4 da T3, waɗanda ke saita saurin kusan komai: yadda jiki ke ƙona kuzari, bugun zuciya, zafin jiki, narkewar abinci, jinin al'ada, yanayin rai da yadda fata da gashi ke girma.
Glandar tana karɓar umarni daga TSH (thyroid-stimulating hormone), wanda glandar pituitary da ke cikin ƙwaƙwalwa ke fitarwa. Idan hormone na thyroid ya ragu, TSH yana hawa don ya ƙara tura thyroid ta yi aiki; idan ya yi yawa, TSH yana sauka. Shi ya sa TSH ne gwajin jini na farko da likitoci ke amfani da shi.
Matsalolin thyroid ruwan dare ne, musamman a mata: ƙungiyar American Thyroid Association ta ce mata sun fi maza samun su sau biyar zuwa takwas, kuma kusan mace ɗaya cikin takwas za ta kamu da cutar thyroid a rayuwarta. A wani bincike a birane takwas na Indiya, kusan babba ɗaya cikin goma yana da ƙarancin aikin thyroid, da yawa ba tare da sun sani ba.



