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.
在你的脖子旁一個小器官, 具掌控你身體的巨大力量, 這就是甲狀腺。 就像一個公司的營運經理, 它的作用是確保 你體内的细胞正常工作。 它通過使用賀爾蒙 發送訊息給每一個細胞。 這種高級器官由甲狀腺小葉組成, 每個小葉都包含稱為濾泡的小細胞, 其中存儲可由甲狀腺 送至血液的賀爾蒙。 它分泌了兩種最重要的賀爾蒙, 甲狀腺素和三碘甲狀腺氨酸 或稱為T3和T4。 作為信使,賀爾蒙的工作 是指導體內的每一個細胞 藉由消耗的氧氣和營養, 來維持人體的新陳代謝。 一系列的反應使 我們的細胞供給我們能量。 這種來自甲狀腺荷爾蒙的通知, 使心臟泵血更有效, 並使得我們的細胞 分解營養成分更快。 當你需要更多能量時, 甲狀腺幫忙透過 發送賀爾蒙增加新陳代謝, 最終,甲狀腺控制細胞 使用能源、生長和繁殖。 甲狀腺被腦垂腺控制, 此大腦深處的荷爾蒙腺體 負責監督甲狀腺的工作, 確保它知道何時發送其賀爾蒙。 腦垂腺的作用是檢測 血液中的賀爾蒙 如果過低或過高, 它就會發出指令, 調節甲狀腺的賀爾蒙。 然而,即使在這樣嚴格的控制系統下, 管理有時仍會產生疏失。 如某些特定疾病 發生在甲狀腺, 或體內化學失衡時可能使甲狀腺混淆, 使其無法接收腦垂腺的指導命令。 第一個問題會導致甲狀腺功能亢進, 當腺體發出過多的賀爾蒙, 意味著將使細胞超載, 消耗過多的養分和氧氣。 它們過度活躍,結果 甲狀腺功能亢進症患者 具較高的新陳代謝率, 顯現出較快的心跳、 常有飢餓感,並快速減肥。 他們還覺得熱、出汗、焦慮, 並難以入睡。 與此相反的問題是 甲狀腺功能減退症, 這發生在甲狀腺發送太少賀爾蒙時, 意味著身體的細胞沒有 足夠多的訊息引導它們活動。 結果,細胞缺乏活力、新陳代謝減慢。 患有甲狀腺功能減退症 會有體重增加的症狀, 以及呆滯、對冷敏感、 關節腫脹和情緒低落。 幸運的是這可以醫治, 能觸發甲狀腺再次活耀起來, 並恢復身體到一個穩定的代謝率。 對於這樣一個小的器官, 甲狀腺握有很多可怕的權力。 但是,健康的甲狀腺 能有效地管理我們的細胞, 讓我們身體平穩運作, 以至於我們沒有注意到它的存在。