with your hands on your hips for 30 seconds. Keep your feet and hands as still as possible.

雙手放在臀部，持續30秒。雙腳和雙手儘量保持不動。

If your hands lift off your hips, you lose a point. If your toes come off the ground,

如果你的手從臀部抬起來，你就會失去一分。如果你的腳趾離地。

you lose a point. If that's too easy, close your eyes. That should've made it harder,

你失去了一個點。如果太簡單，就閉上眼睛。這應該讓它更難。

but not impossible. With your eyes still closed, put your hands

但並非不可能。閉上你的眼睛，把你的手

hands over your ears. That should've made it harder, but why?

手捂住耳朵這應該會讓你更難受，但為什麼？

Yes, you changed your balance point to be more top heavy, but you also changed

是的，你改變了你的平衡點，使其更加上重下輕，但你也改變了。

one of your primary ways of establishing balance — your ears. While balancing on one foot

你建立平衡的主要方式之一--你的耳朵。當單腳平衡時

makes for a fun little challenge, this phenomenon also explains the sensation of vertigo. So

使得一個有趣的小挑戰，這種現象也解釋了眩暈的感覺。所以

in this video, we'll go over the delicate anatomy that gives us our sense of balance.

在這段視頻中，我們將走過微妙的解剖學，給我們的平衡感。

To understand how our ears influence balance, we'll need some background anatomy. Anatomists

為了瞭解我們的耳朵如何影響平衡，我們需要一些背景解剖學。解剖學家

typically divide the ear into three main sections: the outer, middle, and inner ear. The outer

通常將耳朵分為三大部分：外耳、中耳、內耳。外耳

ear includes everything you see on the surface plus the ear canal — mostly elastic cartilage

耳朵包括你所看到的一切，加上耳道--主要是彈性軟骨。

wrapped in skin that's rich with sebaceous oil glands and ear wax glands. At this point,

包裹在皮脂腺和耳蠟腺豐富的皮膚中。此時。

the purpose of the ear is just to collect sound waves, kind of like how a satellite

耳朵的作用只是收集聲波，有點像衛星的作用

dish is concave to collect radio waves. Those sound waves rattle the eardrum, or tympanic

碟子是凹的，用來收集無線電波。這些聲波敲擊耳膜，或鼓膜。

membrane, an extremely thin membrane that amplifies and transmits sound waves to the

膜，是一種極薄的膜，可以將聲波放大並傳遞到

three smallest bones in our bodies — the hammer, anvil, and stirrup or malleus, incus,

我們身體裡最小的三塊骨頭--錘子、鐵砧和馬鐙或馬蹄鐵，incus。

and stapes if you want to use Latin. Then those vibrations wiggle the cochlea in the

和stapes，如果你想用拉丁語。然後，這些振動晃動耳蝸在。

inner ear, which transforms vibrations into nervous impulses that travel to the brain

內耳，將振動轉化為神經衝動，傳入大腦

and get interpreted as your favorite Tiktok song. This is my how do you do, fellow kids

並被演繹成你最喜歡的提克托克歌曲。這是我怎麼做的，小朋友們

moment isn't it? Right next to the cochlea is the tiny vestibular system, which includes

瞬間不是嗎？緊挨著耳蝸的是微小的前庭系統，其中包括了

three semicircular canals, and tiny segments called the utricle and saccule, all of which

三條半圓形的管道，以及被稱為 "胞宮 "和 "囊袋 "的微小部分，所有這些都是

are filled with fluid. These things are the main organs for balance. If we shrunk down

是充滿液體的。這些東西是平衡的主要器官。如果我們縮小

into the semicircular canals, we'd find a space lined with little sensory cells called

在半圓形的管道中，我們會發現有一個空間，裡面有一些小的感覺細胞，叫作 "感覺細胞"。

hair cells, named so because they poke out of the canal a little bit — not because

毛細胞，之所以如此命名，是因為它們從管子裡伸出來一點點--而不是因為

they're actual hair. Whenever we turn or tilt our heads, the inner ear moves with it,

他們是真正的頭髮。每當我們轉頭或仰頭時，內耳就會隨之移動。

and the fluid inside the canals sloshes back and forth. And that movement of the fluid

而運河內的液體來回滑動。而這種液體的運動

pushes on the hair cells, which are sensitive enough to detect less than a nanometer's

推動毛細胞，它的靈敏度足以檢測到小於一納米的毛細胞。

length worth of movement. Each of those canals detects motion on a different axis — one

值得運動的長度。每一個通道都能檢測到不同軸線上的運動--一個軸線上的運動。

detects tilting up or down, one detects rotation, and one detects bending left or right. The

檢測上下傾斜，一個檢測旋轉，一個檢測左右彎曲。該

other organs, the utricle and saccule, works similarly. They both have those hair cells,

其他的器官 胞衣和囊衣的工作原理是相似的。它們都有這些毛細胞。

but they have tiny calcium crystals on them. That makes this part of the balance organ

但它們上面有細小的鈣晶體。這使得這部分平衡器官

specialized to detect acceleration. I personally picture the balance organs like those spirit

專門用來檢測加速度的。我個人認為平衡器官就像那些精神

levels with the bubbles inside them. But instead of our eyes determining the position of the

的水準與裡面的氣泡。但是，我們的眼睛並沒有確定這些氣泡的位置。

bubble visually, the sensors are built into the level. From there, the balance organs

保麗龍視覺，傳感器內置在水準。從那裡，平衡機關

work like any other sense. They convert the motion from the hair cells into nervous impulses

像其他感覺一樣工作。它們將毛細胞的運動轉化為神經衝動。

and send them to the brain. There, they combine with information like what your eyes are focusing

並將它們發送到大腦。在那裡，它們與資訊結合起來，比如你的眼睛正在關注的東西

on, or the position of your foot, or the stretch of certain tendons. But every now

或你腳的位置，或某些肌腱的伸展。但每當

and then, those different inputs conflict with each other like when you're on a boat

然後，這些不同的輸入互相沖突 就像你在船上一樣

or airplane, which manifests as dizziness or even nausea. Unfortunately, all of these

或飛機，表現為頭暈甚至噁心。不幸的是，所有這些

sensory systems break down as you get older. So it's no surprise that the elderly are

隨著年齡的增長，感覺系統會出現故障。所以，老人家也就不足為奇了。

at a drastically increased risk of experiencing dizziness and falls over their younger selves.

比起年輕時的自己，出現頭暈和跌倒的風險大大增加。

While just about every part of your balance organs deteriorates over time, you start losing

當你的平衡器官的每一個部分都隨著時間的推移而退化時，你就會開始失去。

hair cells as you age which contributes to impaired balance. But even before you start

頭髮細胞隨著年齡的增長，會導致平衡受損。但即使在您開始

aging, if you have a disease or injury that affects the inner ear, there's a good chance

衰老，如果你有影響內耳的疾病或損傷，很有可能是

it'll throw off your balance. The most common cause of vertigo in adults is called benign

它會讓你失去平衡。成人最常見的眩暈原因叫做良性眩暈

paroxysmal positional vertigo, or BPPV, and it happens when some of the crystals in the

陣發性位置性眩暈，或稱BPPV，它發生在一些晶體的時候。

inner ear become dislodged from where they usually are. Or there's Meniere's disease

內耳會從平時的位置脫落。或者是美尼爾氏病。

which is an inner ear disorder that might be caused by abnormal buildup of fluid in

這是一種內耳疾病，可能是由於內耳積液異常引起的。

the balance organs — scientists aren't totally sure why it happens. This causes vertigo

平衡器官--科學家們還不完全確定為什麼會發生這種情況。這將導致眩暈

and ringing in the ears, although typically just one ear. So it's a bit of a tradeoff.

和耳鳴，雖然一般只是一隻耳朵。所以這就有點得不償失了。

We have this intricate, three dimensional system for detecting our position in space,

我們有這個複雜的三維繫統來檢測我們在空間的位置。

but it's delicate. I wish I could give you hope, or tell you the one secret doctors don't

但它是微妙的。我希望我能給你希望 或者告訴你一個醫生不知道的祕密

want you to know, but it's a fact of life. You get old, systems break down, then you

想讓你知道，但這是生活的事實。你老了，系統崩潰，然後你

die. Well… Thanks for watching Human. Speaking of things coming to an end, this episode marks

死吧好吧，謝謝你看 "人類"。說到即將結束的事情，這一集標誌著：

the end of season 2 of Human. Don't worry, we're still working on videos behind the

《人類》第二季的結尾。別擔心，我們還在製作 "人類 "背後的視頻。

scenes, so make sure to subscribe to us here on Youtube and drop a comment if you have

場景，所以一定要在Youtube上訂閱我們，如果你有

a topic you want me to cover in Season 3. Thanks for watching. 

你希望我在第三季中涉及的話題。謝謝你的觀看