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  • If you lined up all the blood vessels in your body,

    假如你將身體內所有血管排成一直線

  • they'd be 95,000 kilometers long

    它們將會有 95,000 公里這麼長

  • and everyday, they carry the equivalent of over 7,500 liters of blood,

    每一天,它們都裝載了相當於 7,500 公升的血液

  • though that's actually the same four or five liters recycled over and over,

    不過真正只有五到六公升在不斷循環

  • delivering oxygen, and precious nutrients

    藉以運輸氧氣和其他珍貴的養份

  • like glucose and amino acids to the body's tissues.

    ,像是葡萄糖和胺基酸,到身體的組織

  • All that blood exerts a force on the muscular walls of the blood vessels.

    血液會對血管壁上的肌肉施加一力量

  • That force is called blood pressure,

    這力量就稱為「血壓」

  • and it rises and falls with the phases of the heartbeat.

    它會隨著心跳的收張而升降

  • It's highest during systole,

    在收縮時達到最高點

  • when the heart contracts to force blood through the arteries.

    當心臟壓縮推動血液進入動脈

  • This is your systolic blood pressure.

    這就是你的收縮壓

  • When the heart is at rest between beats,

    當心臟處於兩次跳動中間靜止狀態時

  • blood pressure falls to its lowest value, the diastolic pressure.

    血壓會降到一個最低值,這就是舒張壓

  • A typical healthy individual produces a systolic pressure

    一個標準健康的人,收縮壓

  • between 90 and 120 millimeters of mercury,

    會在 90 到120 公厘水銀柱

  • and diastolic pressure between 60 and 80.

    而舒張壓則會是 60 到 80

  • Taken together, a normal reading is a bit less than 120 over 80.

    綜合起來,正常的血壓讀值應該稍微低於 120 以及 80

  • The blood traverses the landscape of the body

    血液會經由循環系統的輸送管

  • through the pipes of the circulatory system.

    穿越整個壯闊的身體

  • In any plumbing system,

    在任何管道系統中

  • several things can increase the force on the walls of the pipes:

    許多東西都可能增加管壁的壓力

  • the properties of the fluid,

    液體的特性

  • extra fluid,

    額外的液體

  • or narrower pipes.

    或是較細的管道

  • So if the blood thickens,

    所以,假如血液較濃稠

  • a higher pressure is needed to push it, so the heart will pump harder.

    就需要用更大的壓力去推送,所以心臟會打得更用力

  • A high-salt diet will lead to a similar result.

    高鹽的飲食也會導致同樣的結果

  • The salt promotes water retention,

    鹽份會促進水份的保留

  • and the extra fluid increases the blood volume and blood pressure,

    然後這額外的液體就會增加血液量和血壓

  • and stress, like the fight or flight response,

    再來是壓力,像是戰鬥或是逃跑反應

  • releases hormones, like epinephrine and norepinephrine

    這會釋放荷爾蒙,像是腎上腺素和去甲腎上腺素

  • that constrict key vessels,

    這會壓縮關鍵的血管

  • increasing the resistance to flow and raising the pressure upstream.

    增加流動的阻力,然後提高上游的壓力

  • Blood vessels can usually handle these fluctuations easily.

    血管能夠輕易地經常處理這些變動

  • Elastic fibers embedded in their walls make them resilient,

    裡頭嵌有彈性纖維,這讓血管壁富有彈性

  • but if your blood pressure regularly rises above about 140 over 90,

    但假如你的血壓經常性地超過 140 與 90

  • what we call hypertension, and stays there,

    我們所謂的高血壓,並且停留在這種高壓

  • it can cause serious problems.

    可能會導致嚴重的問題

  • That's because the extra strain on the arterial wall

    這是因為過度的張力施加在動脈管壁上

  • can produce small tears.

    可能造成小裂縫

  • When the injured tissue swells up,

    當受傷的組織腫大

  • substances that respond to the inflammation,

    對發炎有反應的物質

  • like white blood cells, collect around the tears.

    ,像是白血球,會聚集在裂縫附近

  • Fat and cholesterol floating in the blood latch on, too,

    漂浮在血管內的脂肪跟膽固醇也會占據此處

  • eventually building up to form a plaque

    最終組合起來成為血小板

  • that stiffens and thickens the inner arterial wall.

    這動使得動脈管壁變得堅硬厚實

  • This condition is called atherosclerosis,

    這狀況稱為「動脈硬化症」

  • and it can have dangerous consequences.

    而這會造成可怕的後果

  • If the plaque ruptures, a blood clot forms on top of the tear,

    假如血小板斷裂,在裂縫處上方會產生血塊

  • clogging the already narrowed pipe.

    阻礙原本已經很窄的管道

  • If the clot is big enough,

    如果血塊夠大

  • it can completely block the flow of oxygen and nutrients to cells downstream.

    會使得要輸送到身體末梢的氧氣以及養份完全被擋住

  • In vessels that feed the heart,

    如是在要送回心臟的血管上

  • that will cause a heart attack,

    當氧氣無法送達,心肌細胞會逐漸死去

  • when oxygen-deprived cardiac muscle cells start to die.

    就會導致心臟病

  • If the clot cuts off blood flow to the brain,

    假如血塊切斷到大腦的血流

  • it causes a stroke.

    就會導致中風

  • Dangerously clogged blood vessels can be widened

    藉由一種名為「血管成型術」的手術,

  • by a procedure called an angioplasty.

    危險地阻塞的血管可以被加寬

  • There, doctors thread a wire through the vessel

    醫生穿過一跟線到血管裡

  • to the obstructed site,

    直到阻塞的地方

  • and then place a deflated balloon catheter over the wire.

    然後經由線導入一個癟氣球

  • When the balloon is inflated, it forces the passageway open again.

    當汽球充氣後,會強迫通道再度打開

  • Sometimes a rigid tube called a stent

    有時,則會放入一種堅硬的管子,稱為支架

  • is placed in a vessel to held hold it open,

    來讓血管保持撐開的狀態

  • letting the blood flow freely

    讓血流可以順暢

  • to replenish the oxygen-starved cells downstream.

    然後肢體末梢的缺氧細胞就能夠再度補充到氧氣

  • Staying flexible under pressure is a tough job for arteries.

    在壓力下保持彈性對動脈來說是個艱困的工作

  • The fluid they pump is composed of substances

    它們抽送的液體裡包含很多物質

  • that can get sticky and clog them,

    這些物質會讓液體變黏並把它們阻塞

  • and your typical healthy heart beats about 70 times a minute,

    你的標準心跳數約是每分鐘 70 下

  • and at least 2.5 billion times during an average lifetime.

    平均一生會至少跳動 25 億下

  • That may sound like an insurmountable amount of pressure,

    這聽起來像是會有難以想像的壓力施加在上面

  • but don't worry, your arteries are well suited for the challenge.

    但別擔心,你的動脈是非常能夠適應這種挑戰的

If you lined up all the blood vessels in your body,

假如你將身體內所有血管排成一直線

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B2 中高級 中文 美國腔 TED-Ed 血管 動脈 液體 血液 壓力

【TED-Ed】血壓是如何工作的--威爾弗雷德-曼薩諾。 (【TED-Ed】How blood pressure works - Wilfred Manzano)

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    SylviaQQ 發佈於 2021 年 01 月 14 日
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