Plasma血漿
A pale yellow liquid, mostly water, with food, waste, and messages dissolved in it.
淡黃色的液體，大部分是水，裡面溶著養分、廢物和訊息。
The Human Body · Lesson 27 · 人體探索 第27課
What Is in a Drop of Blood?一滴血裡有什麼？
Zoom into one drop: red cells, white cells, platelets, and the liquid that carries them. Watch each one do its job in 3D, and find out how much blood you have.
把鏡頭對準一滴血：紅血球、白血球、血小板，還有載著它們的液體。在 3D 裡看它們各做各的工作，再算算你全身有多少血。
Big idea · 一句話看懂
Blood is a liquid full of cells, and each kind has one job: carry oxygen, fight germs, or plug a leak.
血液是裝滿細胞的液體，每一種細胞各做一件事：載氧氣、打病菌，或是堵住漏洞。
3D Model · 3D 模型
Dive into a Drop 潛進一滴血
A single drop of blood sits on a glass slide, the kind used with a microscope. Press play, or drag the slider: every step takes you ten times closer. At first the drop is simply red. Then, at about the width of a hair, it turns into a crowd. At the last stop, choose a job to watch: a red cell picking up oxygen, a white cell catching a germ, or platelets plugging a hole. The glass tube on the right shows what you get when blood is left to settle.
一滴血放在一片載玻片上——就是顯微鏡用的那種玻璃片。按播放，或是拖動滑桿：每一步都靠近十倍。一開始，那滴血就只是紅色的；到了大約一根頭髮的寬度，它忽然變成擠滿了東西的一大群。到最後一站，選一件工作來看：紅血球接氧氣、白血球抓細菌，或是血小板堵住破洞。右邊那根玻璃管，是把血液靜置之後會看到的樣子。
Loading… · 載入中…
Drag to turn · 拖曳旋轉 Scroll or pinch to zoom · 滾輪／雙指縮放
Magnified 1 times · 放大 1 倍
This 3D model needs WebGL, which this browser does not support. The blood tool and the cards below still work.
這個瀏覽器不支援 WebGL，無法顯示 3D 模型；下方的血量工具和卡片一樣能用。
How much blood? · 有多少血？
5liters of blood公升的血
This number stays on this screen. It is not saved or sent anywhere.這個數字只留在這個畫面上，不會儲存，也不會傳到任何地方。
How many cells? · 有多少血球？
🔴—red blood cells個紅血球
⚪—white blood cells個白血球
🩹—platelets片血小板
- Red discs: red blood cells
紅色的圓盤：紅血球 - Pale ball: a white blood cell
淡色的球：白血球 - Small yellow chips: platelets
黃色的小碎片：血小板 - Green rod: a germ
綠色的桿子：細菌 - Straw-colored liquid: plasma
稻草色的液體：血漿
The hand bones are real shapes from BodyParts3D; everything else is our own drawing, with the sizes kept roughly right at each step. Real blood is far more crowded than we can show: nearly half of every drop is red cells. We drew one white cell among a few hundred red cells so that you can find it; in real blood there is about one for every 700. The colors are brighter than real cells, which look pale under a microscope until they are stained.
手的骨頭是 BodyParts3D 的真實形狀；其餘都是本站自繪的示意圖，每一站的大小比例大致是對的。真正的血液比這裡畫的擠得多：每一滴血有將近一半都是紅血球。我們在幾百個紅血球裡畫了一個白血球，好讓你找得到；在真正的血液裡，大約每 700 個紅血球才有一個白血球。顏色也比真的鮮豔——在顯微鏡下，這些細胞要染色之後才看得清楚。
Bone model: BodyParts3D, © The Database Center for Life Science, licensed under CC BY 4.0. We selected the bones of the hand, simplified the shapes, and turned the model upright; the slide, the drop, and the blood cells are our own drawing. · 骨骼模型來源：BodyParts3D（日本生命科學資料庫中心，CC BY 4.0 授權）；本站挑選手的骨頭、簡化形狀並轉正方向，載玻片、血滴與血球為本站自繪示意。
Reading · 英文閱讀
27
Unit 27: What Is in a Drop of Blood?
Blood looks like a simple red liquid, like paint. But if you look at one drop under a microscope, you will find it is full of living things. In fact, a drop of blood is more like a busy river full of boats than like paint.
血看起來是很單純的紅色液體，像顏料一樣。可是如果把一滴血放到顯微鏡下面，你會發現裡面全是活的東西。其實，一滴血不像顏料，倒比較像一條擠滿了船的繁忙河流。
The river itself is called plasma. It is a pale yellow liquid, mostly water, and it makes up a little more than half of your blood. Plasma carries food from your intestines, waste on its way to your kidneys, and chemical messages from one part of the body to another. Everything else floats in it.
這條河本身叫做血漿。它是淡黃色的液體，大部分是水，占了血液的一半多一點。血漿載著從腸子來的養分、要送去腎臟的廢物，還有從身體的一處傳到另一處的化學訊息。其他的一切都漂在它裡面。
Most of the boats are red blood cells. They are soft discs with a dent on each side, and they are packed with a red substance that contains iron. Oxygen sticks to the iron, so red cells can carry oxygen from your lungs to every part of you. There are about five million red cells in a drop of blood the size of a pinhead. They are what make blood red: bright red when they are full of oxygen and darker red when they are not. Blood is never blue.
大部分的船是紅血球。它們是軟軟的圓盤，兩面各凹下去一塊，裡面塞滿一種含鐵的紅色物質。氧氣會黏在鐵上，所以紅血球可以把氧氣從肺載到身體的每個地方。針頭那麼大的一小滴血裡，就有大約五百萬個紅血球。血是紅色的，就是因為它們：裝滿氧氣的時候鮮紅，沒有的時候暗紅。血從來不是藍色的。
White blood cells are the guards. There are far fewer of them, about one for every 700 red cells, but they are bigger, and they can crawl. When germs get in, white cells chase them and swallow them, as you learned in the lesson about fighting germs.
白血球是守衛。它們的數目少得多——大約每 700 個紅血球才有一個——可是它們比較大，而且會爬。病菌闖進來的時候，白血球會追上去，把它們吞掉，就像你在對抗病菌那一課學到的。
Platelets are the repair crew. They are not even whole cells, only tiny pieces of cell. When a blood vessel is cut, platelets stick to the edges of the hole and to each other and plug it. Sticky threads then form a net over the plug. That is how a cut stops bleeding.
血小板是修理隊。它們甚至不算完整的細胞，只是細胞的小碎片。血管被割破的時候，血小板會黏到破洞的邊緣、再一個黏一個，把洞塞住；然後黏黏的絲在上面織成一張網。傷口就是這樣止血的。
All three kinds are made in the soft marrow inside your bones, millions of them every second, because blood cells wear out. A red cell lasts about four months, and a platelet lasts only about nine days. A grown-up has about five liters of blood. Children have less, because they are smaller. Blood is about one fourteenth of your body's weight. Blood also comes in different types, such as A, B, AB, and O. That is why hospitals check a person's type before giving blood from someone else.
這三種全都是在骨頭裡軟軟的骨髓製造的，每秒鐘好幾百萬個，因為血球會用舊。一個紅血球大約能用四個月，一片血小板只能用大約九天。一個大人大約有五公升的血；小朋友比較少，因為身體比較小。血液大約占體重的十四分之一。另外，血還分成不同的血型，例如 A、B、AB 和 O——所以醫院在把別人的血輸給病人之前，一定會先檢查血型。
Read aloud · 課文朗讀
Questions · 閱讀理解
What is plasma, and what does it carry?
The pale yellow liquid part of blood. It carries food, waste, and chemical messages, and the blood cells float in it.
What are the jobs of red blood cells, white blood cells, and platelets?
Red cells carry oxygen, white cells fight germs, and platelets plug holes in blood vessels.
Where are blood cells made, and why must the body keep making them?
In the marrow inside the bones. The body keeps making them because blood cells wear out: a red cell lasts about four months and a platelet about nine days.
Words & Phrases · 生字及片語
blood(n.)血；血液Blood carries oxygen around your body.血液把氧氣帶到全身。drop(n.)一滴A drop of rain fell on my nose.一滴雨落在我的鼻子上。liquid(n.)液體Water is a liquid.水是一種液體。carry(v.)運送；攜帶Red blood cells carry oxygen.紅血球運送氧氣。germ(n.)病菌Wash your hands to get rid of germs.洗手可以把病菌洗掉。plug(v.)塞住；堵住We used a cloth to plug the hole.我們用一塊布把洞塞住。float(v.)漂浮The leaves float on the pond.葉子漂在池塘上。type(n.)類型；血型Do you know your blood type?你知道自己的血型嗎？
Quick Check · 小測驗
1. What is the liquid part of blood called?
2. Which blood cells carry oxygen?
3. What do platelets do?
4. Where are blood cells made?
5. What color is blood that has given up its oxygen?
The Crew · 船員
One river, three kinds of boats 一條河，三種船
If you let blood stand in a glass tube, it settles into layers: straw-colored plasma on top, a dark red layer of red cells at the bottom, and a thin pale line between them. That thin line holds all the white cells and platelets.
把血液靜置在玻璃管裡，它會分層：上面是稻草色的血漿，下面是暗紅色的紅血球，中間夾著薄薄一條淡色的線——所有的白血球和血小板，都在那條細線裡。
Red blood cells紅血球
Soft discs with no nucleus, full of iron. Each one lasts about four months.
沒有細胞核的軟圓盤，裡面裝滿了鐵。每一個大約用四個月。
White blood cells白血球
Bigger than red cells, with a nucleus. They can crawl out of the blood to where they are needed.
比紅血球大，有細胞核。它們可以爬出血管，到需要它們的地方去。
Platelets血小板
Pieces of cell, not whole cells. Each one lasts about nine days.
細胞的碎片，不是完整的細胞。每一片大約用九天。
Bone marrow骨髓
The factory. It turns out millions of new blood cells every second.
工廠。它每秒鐘製造好幾百萬個新的血球。
Measure Yourself · 親身測量
How much blood do I have? 我有多少血？
Blood is about one fourteenth of the body's weight, so the tool below the model can estimate yours. The number stays on your screen: it is not saved or sent anywhere, and the tool shows only the blood.
血液大約占體重的十四分之一，所以模型下方的工具可以幫你估算。數字只留在你的螢幕上，不會儲存，也不會傳到任何地方；工具只顯示血量。
- ⚖️Type your weight · 輸入體重Type in your weight in kilograms. If you would rather not, skip this step: the tool also shows a grown-up's five liters.輸入你的體重（公斤）。如果不想輸入，可以跳過這一步：工具也會顯示大人的五公升是多少。
- 🧴Count the bottles · 數瓶子The tool turns your blood into bottles of 600 milliliters, the size of a drink bottle.工具會把你的血量換成幾瓶 600 毫升的寶特瓶——就是一般飲料瓶的大小。
- 🩸Count the cells in a drop · 數一滴血裡的血球Then tap a button to see how many cells are in a pinhead of blood, in one drop, or in a teaspoon.再點按鈕，看看針頭大的一小滴、一滴，或是一茶匙的血裡有多少血球。
Myth vs. Fact · 常見迷思
Four things people get wrong 四個常見的誤會
✗ Myth · 迷思The blood in your veins is blue.靜脈裡的血是藍色的。
✓ Fact · 事實Blood is always red: bright red with oxygen, darker red without. Veins only look blue through your skin.血永遠是紅色的：有氧氣時鮮紅，沒有時暗紅。靜脈只是隔著皮膚看起來偏藍。
✗ Myth · 迷思Blood is a red liquid all the way through.血從裡到外都是紅色的液體。
✓ Fact · 事實More than half of blood is pale yellow plasma. The red comes from the cells floating in it.血液有一半以上是淡黃色的血漿。紅色來自漂在裡面的細胞。
✗ Myth · 迷思Once you lose some blood, it is gone for good.流掉的血就永遠沒有了。
✓ Fact · 事實Your bone marrow makes millions of new blood cells every second.骨髓每秒鐘都在製造好幾百萬個新的血球。
✗ Myth · 迷思Your blood type decides your personality.血型決定一個人的個性。
✓ Fact · 事實Studies have not found a link. Blood type matters when someone needs blood from another person.研究並沒有發現這樣的關聯。血型重要的地方，是在需要輸別人的血的時候。
Remember It · 記憶口訣
Blood in a sentence 一句話記住血液
A river full of boats一條擠滿船的河
Plasma is the river. The cells are the boats.
血漿是河，血球是船。
Red carries, white fights, platelets plug紅的載、白的打、血小板堵
Oxygen, germs, and leaks: one job each.
氧氣、病菌、漏洞：一種管一件事。
Made in the marrow骨髓製造
Millions of new cells every second, inside your bones.
在你的骨頭裡，每秒鐘好幾百萬個新的血球。
Never blue從來不是藍色的
Bright red with oxygen, darker red without.
有氧氣時鮮紅，沒有時暗紅。
In Chinese · 中文怎麼說
Thicker Than Water 血濃於水
English and Chinese share a proverb, almost word for word: “Blood is thicker than water,” 血濃於水 (xuè nóng yú shuǐ). Both mean that family ties are stronger than any others. And it is true in the plain sense as well: with all those cells in it, blood really is thicker than water! The two languages part ways on one phrase, though. In Chinese, 熱血 (rèxuè), “hot blood,” is praise for someone full of energy and ideals. In English, a “hot-blooded” person is someone who gets angry easily. In Taiwan you will also see the slogan 捐血一袋，救人一命: “Give one bag of blood, save one life.” Blood cannot be made in a factory, so it has to come from people who choose to give it.
英文和中文有一句幾乎一模一樣的諺語：Blood is thicker than water——「血濃於水」，意思都是親情比什麼都深。照字面看，這句話也是對的：裡面有那麼多細胞，血真的比水濃！不過有一個詞，兩種語言走了不同的路：中文的「熱血」是稱讚一個人有幹勁、有理想；英文的 hot-blooded 卻是說一個人容易發脾氣。在台灣，你還會看到這句標語：「捐血一袋，救人一命。」血沒辦法在工廠裡製造，只能來自願意捐出來的人。
Classroom Activity 1 · 課堂活動一
Blood in a Bottle 瓶子裡的血液
You need · 準備材料
- A clear bottle or jar with a lid一個有蓋子的透明瓶子或罐子
- Water with a little yellow food coloring, or weak tea加了一點黃色食用色素的水，或是淡茶
- Red beads or dried red beans, one large white bean, and a pinch of rice紅色的珠子或紅豆、一顆大的白豆，還有一小撮米
Steps · 步驟
- Fill the bottle a little more than halfway with the yellow water. This is the plasma.把黃色的水倒到比半瓶多一點。這是血漿。
- Add red beads until the bottle is nearly full. These are the red blood cells.加進紅色的珠子，直到瓶子快滿。這些是紅血球。
- Add the one white bean and the pinch of rice: a white blood cell and some platelets.加進那一顆白豆和一小撮米：一個白血球和一些血小板。
- Close the lid and tip the bottle gently. Then let it stand. What happens?蓋上蓋子，輕輕搖一搖，再靜置。發生了什麼事？
Teaching tip: the heavier beads sink and the liquid clears above them, much as real blood settles in a tube. Ask how hard it is to find the one white bean: in real blood, the red cells outnumber the white cells by about 700 to 1.
教學提示：比較重的珠子會沉下去，上面的液體變清——和真正的血液在試管裡分層很像。可以問學生：那一顆白豆好不好找？在真正的血液裡，紅血球和白血球的比例大約是 700 比 1。
Classroom Activity 2 · 課堂活動二
Bright Red, Dark Red 鮮紅和暗紅
You need · 準備材料
- Red and dark red paper circles, about twenty of each鮮紅色和暗紅色的紙圓片，各約二十個
- Three signs: LUNGS, HEART, MUSCLES三張牌子：肺、心臟、肌肉
Steps · 步驟
- Put the three signs in a big triangle on the floor. Students are red blood cells.把三張牌子在地上排成一個大三角形。學生是紅血球。
- At LUNGS, pick up a bright red circle: you have loaded oxygen.到「肺」那裡，拿一張鮮紅色的圓片：你裝上氧氣了。
- Walk past HEART to MUSCLES, and swap it there for a dark red circle: you have delivered the oxygen.經過「心臟」走到「肌肉」，在那裡換成一張暗紅色的圓片：你把氧氣送到了。
- Walk past HEART again and back to LUNGS. How many trips can you make in one minute?再經過「心臟」回到「肺」。一分鐘可以跑幾趟？
Teaching tip: this acts out the two loops from the lesson about the heart. Point out that nobody ever carries a blue circle: blood that has delivered its oxygen is dark red.
教學提示：這是把心臟那一課的兩個循環演出來。請特別指出：沒有人拿過藍色的圓片——送完氧氣的血是暗紅色的。
⚕ Health note · 健康提醒This lesson is for learning about the body. It is not medical advice. The amount of blood shown by the tool is an estimate for learning, not a medical measurement. Never touch another person's blood: tell an adult instead. If a cut will not stop bleeding, press on it with a clean cloth and get an adult's help right away.本課是認識身體的教材，不是醫療建議。工具算出來的血量只是學習用的估計，不是醫學上的測量。絕對不要碰別人的血——請告訴大人。如果傷口一直止不住血，用乾淨的布壓住，並且馬上請大人幫忙。