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  • 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.

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

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B2 US TED-Ed thyroid metabolism organ pituitary sends

【TED-Ed】How does the thyroid manage your metabolism? - Emma Bryce

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    稲葉白兎 posted on 2015/03/07
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