Nestled in the tissues of your neck is a small unassuming organ that wields enormous power over your body. It's called the thyroid. Like the operations manager in a company, its role is to make sure that the cells in your body are working properly. It does that by using hormones to deliver messages to every single one of them. This high-ranking organ is made up of lobules that each contains smaller cells called follicles, which store the hormones the thyroid sends out into your blood. Two of the most important hormones it produces are thyroxine and triiodothyronine, or T3 and T4. As messengers, the hormone's job is to instruct every cell in the body when to consume oxygen and nutrients. That maintains the body's metabolism, the series of reactions our cells perform to provide us with energy. This hormonal notification from the thyroid gets the heart pumping more efficiently, and makes our cells break down nutrients faster. When you need more energy, the thyroid helps by sending out hormones to increase metabolism. Ultimately, the thyroid allows our cells to use energy, grow and reproduce. The thyroid is controlled by the pituitary gland, a hormonal gland deep in the brain that oversees the thyroid's tasks, making sure it knows when to send out its messengers. The pituitary's role is to sense if hormone levels in the blood are too low or too high, in which case it sends out instructions in the form of the thyroid- stimulating hormone. Even in this tightly controlled system, however, management sometimes slips up. Certain diseases, growths in the thryoid or chemical imbalances in the body can confuse the organ and make it deaf to the pituitary's guiding commands. The first problem this causes is hyperthyroidism, which happens when the organ sends out too many hormones. That means the cells are overloaded with instructions to consume nutrients and oxygen. They become overactive as a result, meaning a person with hyperthyroidism experiences a higher metabolism signaled by a faster heartbeat, constant hunger, and rapid weight loss. They also feel hot, sweaty, anxious, and find it difficult to sleep. The opposite problem is hypothyroidism, which happens when the thyroid sends out too few hormones, meaning the body's cells don't have as many messengers to guide them. In response, cells grow listless and metabolism slows. People with hypothyroidism see symptoms in weight gain, sluggishness, sensitivity to cold, swollen joints and feeling low. Luckily, there are medical treatments that can help trigger the thyroid's activities again, and bring the body back to a steady metabolic rate. For such a little organ, the thyroid wields an awful lot of power. But a healthy thyroid manages our cells so effectively that it can keep us running smoothly without us even noticing it's there.
V tkivih na vašem vratu gnezdi majhen, skromen organ, ki v vašem telesu upravlja z neverjetno močjo. Imenuje se ščitnica. Kot nadzornik v podjetju zagotavlja, da vse celice v vašem telesu pravilno delujejo. To naredi z uporabo hormonov, ki prenesejo sporočila v vsako od njih. Ta zelo pomemben organ je narejen iz lobulov in vsak vsebuje manjše celice, imenovane folikli, ki shranjujejo hormone, ki jih ščitnica pošilja v vašo kri. Dva od najpomembnejših hormonov, ki jih proizvaja, sta tiroksin in trijodotironin, ali T3 in T4. Naloga hormonov je, da kot prenašalci sporočil dajo navodila vsaki celici v telesu, kdaj naj porabi kisik in hranila. To vzdržuje metabolizem telesa, serijo reakcij, ki jih naše celice izvajajo, da nas preskrbijo z energijo. Hormonsko opozorilo iz ščitnice povzroči, da je črpanje srca bolj učinkovito in da se hranila v celicah razgrajujejo hitreje. Ko potrebuješ več energije, ščitnica pomaga tako, da pošlje ven hormone za povečanje metabolizma. Ščitnica navsezadnje dovoli celicam porabo energije, rast in razmnoževanje. Ščitnico nadzoruje hipofiza, hormonska žleza globoko v možganih, ki nadzoruje naloge ščitnice, poskrbi, da ve, kdaj poslati ven svoje prenašalce. Naloga hipofize je zaznati, če je raven hormonov v krvi prenizka ali previsoka, v tem primeru pošlje ven navodila v obliki ščitnico-stimulirajočega hormona. A celo v tem tesno kontroliranem sistemu včasih nadzoru spodrsne. Določene bolezni, razraščanje v ščitnici ali kemično neravnovesje v telesu lahko zmedejo organ in ga naredijo gluhega za ukaze hipofize. Prvi problem, ki ga to povzroči, je hipertiroidizem, ki se zgodi, ko organ pošlje ven preveč hormonov. To pomeni, da so celice preobremenjene z navodili, naj porabljajo hranila in kisik. Zato postanejo preveč aktivne, kar pomeni, da ima oseba s hipertiroidizmom hitrejši metabolizem, ki ga označujejo hitrejši utrip, stalna lakota in hitra izguba teže Prav tako jim je vroče, potijo se, so anksiozni in imajo težave s spanjem. Nasprotni problem je hipotiriodizem, ki nastane, ko ščitnica pošilja ven premalo hormonov. kar pomeni, da celice v telesu nimajo toliko sporočil, ki bi jih vodila. Zato celice stagnirajo in metabolizem se upočasni. Ljudje s hipotirodizmom se zredijo, so počasni, občutljivi na mraz, imajo zatekle sklepe in so potrti. Na srečo obstaja zdravljenje, ki pomaga spet vzpodbuditi aktivnost ščitnice in spravi telo na stabilen metabolni ritem. Čeprav je tako majhna, ima ščitnica res veliko moč. A zdrava ščitnica upravlja z našimi celicami tako učinkovito, da gladko živimo, ne da bi sploh opazili njeno prisotnost.