How does the thyroid manage your metabolism? - Emma Bryce

甲状腺がどのように体の代謝を調整しているのか―エマ・ブライス

翻訳: Naomi Mandel 校正: Reiko Ogura

Nestled in the tissues of your neck is a small unassuming organ

我々の首にある小さな臓器

that wields enormous power over your body.

体の司令塔ともいえる

It's called the thyroid.

甲状腺は

Like the operations manager in a company,

会社にとっての運営部長—

its role is to make sure that the cells in your body are working properly.

体の細胞が正しく機能するよう 管理する役目をし

It does that by using hormones to deliver messages to every single one of them.

ホルモンを使って各細胞に指令を送ります

This high-ranking organ is made up of lobules

この大切な臓器は多くの小葉からなり

that each contains smaller cells called follicles,

その中の小胞と呼ばれる小さな細胞は

which store the hormones the thyroid sends out into your blood.

甲状腺が血管へ送るホルモンを蓄えます

Two of the most important hormones it produces

甲状腺が作る２種類の大事なホルモン

are thyroxine and triiodothyronine, or T3 and T4.

チロキシン（Ｔ４）と トリヨードサイロニン（Ｔ３）は

As messengers, the hormone's job

メッセンジャーとして

is to instruct every cell in the body when to consume oxygen and nutrients.

細胞へ酸素と栄養の吸収を指示し

That maintains the body's metabolism,

新陳代謝を促し

the series of reactions our cells perform to provide us with energy.

細胞が一連の反応を通して 体にエネルギーを供給できるようにするのです

This hormonal notification from the thyroid

甲状腺からのホルモンで

gets the heart pumping more efficiently,

心臓が効率よく血液を循環させるのを助け

and makes our cells break down nutrients faster.

細胞が栄養分解をする過程を速やかにします

When you need more energy,

体がもっとエネルギーを必要とする時は

the thyroid helps by sending out hormones to increase metabolism.

甲状腺はホルモンを送り 新陳代謝を促進させます

Ultimately, the thyroid allows our cells to use energy, grow and reproduce.

最終的に細胞がエネルギーを使い 成長し再生するのを助けます

The thyroid is controlled by the pituitary gland,

甲状腺は 脳深部のホルモン分泌線である

a hormonal gland deep in the brain that oversees the thyroid's tasks,

脳下垂体に制御され

making sure it knows when to send out its messengers.

必要に応じ体中に指示を出しています

The pituitary's role is to sense if hormone levels in the blood

脳下垂体は 血液中のホルモンのレベルが

高すぎないか低すぎないかを感知し

are too low or too high,

in which case it sends out instructions

甲状腺刺激ホルモンの形で

in the form of the thyroid- stimulating hormone.

体中に指示を送ります

Even in this tightly controlled system, however,

これほど綿密な制御体制が敷かれていても

management sometimes slips up.

管理が失敗することもあります

Certain diseases,

ある種の病気や

growths in the thryoid

甲状腺内の腫瘍

or chemical imbalances in the body can confuse the organ

体内の化学的不均衡が甲状腺を混乱させ

and make it deaf to the pituitary's guiding commands.

脳下垂体からの指令を無視したりします

The first problem this causes is hyperthyroidism,

その１つが甲状腺機能亢進症で

which happens when the organ sends out too many hormones.

甲状腺からのホルモン過剰分泌が 原因で起きます

That means the cells are overloaded with instructions

つまり細胞に

to consume nutrients and oxygen.

栄養と酸素を摂取する指示が過剰に行き

They become overactive as a result,

その結果として

meaning a person with hyperthyroidism experiences a higher metabolism

新陳代謝が過剰になり

signaled by a faster heartbeat, constant hunger, and rapid weight loss.

心拍数の増加 過食 体重の急激な減少や

They also feel hot, sweaty, anxious, and find it difficult to sleep.

また発熱 発汗 不安感 不眠症なども症状として現れます

The opposite problem is hypothyroidism,

その反対は 甲状腺機能低下症で

which happens when the thyroid sends out too few hormones,

甲状腺からのホルモン不足で

meaning the body's cells don't have as many messengers to guide them.

細胞に十分な指示が行かず

In response, cells grow listless and metabolism slows.

細胞の働きが鈍り 代謝が低下するのです

People with hypothyroidism see symptoms in weight gain,

症状は体重の増加

sluggishness, sensitivity to cold, swollen joints and feeling low.

倦怠感 冷え性 関節の腫れ うつ などです

Luckily, there are medical treatments

幸い 医学療法を使い

that can help trigger the thyroid's activities again,

甲状腺の働きを正常化させ

and bring the body back to a steady metabolic rate.

体の代謝を健康な状態に戻すことができます

For such a little organ, the thyroid wields an awful lot of power.

小さな臓器でも 甲状腺はとても支配力があります

But a healthy thyroid manages our cells so effectively

正常な甲状腺は細胞を効率的に働かせ

that it can keep us running smoothly without us even noticing it's there.

我々がその存在に気付かないほど スムーズに体の健康を保っているのです