Right atrium右心房
A waiting room for blood that has given away its oxygen.
已經交出氧氣的血，先在這裡等候。
The Human Body · Lesson 3 · 人體探索 第三課
Where Does Your Blood Go?血液在身體裡怎麼流動？
Your heart sends blood around two loops, one to the lungs and one to the whole body. Tap along with your pulse, and the 3D heart beats with you.
心臟把血液送進兩個循環：一個到肺、一個到全身。跟著自己的脈搏點一點，3D 心臟就用你的心跳跳動。
Big idea · 一句話看懂
The heart is two pumps side by side. The right side sends blood to the lungs to pick up oxygen; the left side sends it to the rest of the body.
心臟是並排的兩個幫浦：右邊把血送到肺裡拿氧氣，左邊把血送到全身。
3D Model · 3D 模型
Two Pumps, Two Loops 兩個幫浦、兩個循環
Watch the blood cells flow: dark red on the way to the lungs, bright red after they pick up oxygen. Switch to slow motion to see the valves open and close, follow the glowing drop around both loops, or press Measure my pulse and tap along with your own heartbeat for 15 seconds. The heart in the model will then beat at your speed.
看血球流動：往肺去的時候是暗紅色，拿到氧氣之後變成鮮紅色。切到慢動作，看瓣膜一開一關；跟著發光的那一滴血繞完兩個循環；或按「量我的脈搏」，跟著自己的心跳按 15 秒，模型裡的心臟就會用你的速度跳。
Drag to turn · 拖曳旋轉 Scroll or pinch to zoom · 滾輪／雙指縮放
Drawn as if you are facing the person: their right side is on your left. · 像面對著一個人：他的右邊在你的左邊
This 3D model needs WebGL, which this browser does not support. The cards below still explain everything.
這個瀏覽器不支援 WebGL，無法顯示 3D 模型；下方的卡片一樣能看懂。
Follow one drop · 跟著一滴血
- Right atrium: blood from the body arrives右心房：從全身回來的血進來
- Right ventricle: squeezes it toward the lungs右心室：把血擠向肺
- Pulmonary artery: on the way to the lungs肺動脈：前往肺的路上
- Lungs: drops carbon dioxide, picks up oxygen肺：放下二氧化碳、帶走氧氣
- Pulmonary vein and left atrium: back to the heart肺靜脈、左心房：回到心臟
- Left ventricle: the strongest squeeze左心室：最用力的一擠
- Aorta: out to the whole body主動脈：送往全身
- Capillaries: delivers oxygen and food, picks up waste微血管：送出氧氣與養分、收走廢物
- Veins: back to the heart靜脈：回到心臟
- Bright red: blood rich in oxygen
鮮紅色：含氧多的血 - Dark red: blood low in oxygen. Real blood is never blue.
暗紅色：含氧少的血——真正的血從來不是藍色 - Cream disks: valves, shown closed. They open to let blood through one way.
米色圓片：瓣膜關上時的樣子；打開時只讓血往一個方向流 - Glowing drop: one blood cell you can follow
發光的點：可以跟著走的一顆血球
A simplified model, not real anatomy. The real heart is tilted, with its tip toward the lower left, and the chambers are hidden inside thick muscle walls. The loops are drawn short: in your body, one trip around both loops takes about a minute at rest, not a few heartbeats.
這是簡化的示意模型，不是真實解剖。真正的心臟是斜的，心尖朝左下，腔室藏在厚厚的心肌裡。循環也畫得很短：在身體裡，安靜時血液繞完兩個循環大約要一分鐘，不是幾下心跳。
Reading · 英文閱讀
3
Unit 3: Where Does Your Blood Go?
Press two fingers gently on the thumb side of your wrist. Each little bump you feel is your pulse, and every bump is one squeeze of your heart. Your heart is a muscle about the size of your fist, sitting behind your breastbone between your two lungs. It beats about 100,000 times a day, and in a long life, close to three billion times, without ever stopping to rest.
把兩根手指輕輕放在手腕靠拇指的那一側。你摸到的每一下小小的跳動，就是脈搏，而每一下都是心臟擠壓了一次。心臟是一塊大約拳頭大小的肌肉，位在胸骨後面、兩片肺的中間。它一天大約跳十萬下，長壽的人一輩子會跳將近三十億下，從來不停下來休息。
Why does it work so hard? Every cell in your body needs a steady supply of oxygen and food, and every cell makes waste, such as carbon dioxide, that has to be carried away. Blood is the delivery service. An adult has about five liters of it, and the heart pumps all of it around the body roughly once every minute when you are resting.
它為什麼要這麼努力？身體的每一個細胞都需要源源不絕的氧氣和養分，而每個細胞也會製造廢物，例如二氧化碳，必須被運走。血液就是這套快遞系統。成人全身大約有五公升的血，安靜時，心臟大約每一分鐘就把全部的血送完一圈。
The surprising part is that your heart is really two pumps, side by side, divided by a wall of muscle. The right side collects blood coming back from the body, which has given away much of its oxygen, and pumps it to the lungs. There the blood drops off carbon dioxide and picks up fresh oxygen. The left side collects that oxygen-rich blood from the lungs and pumps it out to the rest of the body. Both sides squeeze at the same moment, so every heartbeat sends blood around both loops at once. The left side has the thickest wall, because it has to push blood all the way to your toes and back.
令人意外的是，心臟其實是兩個並排的幫浦，中間隔著一道肌肉牆。右邊收集從全身回來、已經交出大部分氧氣的血，把它送到肺；血在肺裡放下二氧化碳、帶走新鮮的氧氣。左邊收集從肺回來、充滿氧氣的血，把它送到全身。左右兩邊在同一瞬間收縮，所以每一次心跳都同時把血送進兩個循環。左邊的心壁最厚，因為它得把血一路推到腳趾、再繞回來。
Each pump has two rooms, called chambers. The upper chamber, the atrium, collects blood. The lower chamber, the ventricle, is the strong one that squeezes it out. Between the chambers, and at the exits, are valves, flaps that work like one-way doors. When they snap shut, they make the sound a doctor hears through a stethoscope: lub-dub, lub-dub. The first sound is the doors between the atria and the ventricles closing, and the second is the doors at the exits closing.
每個幫浦都有兩個房間，叫做腔室。上面的心房負責收集血液，下面的心室是強壯的那一個，負責把血擠出去。腔室之間和出口都有瓣膜，也就是像單向門一樣的薄片。它們啪一聲關上時，就發出醫生用聽診器聽到的聲音：噗通、噗通。第一聲是心房和心室之間的門關上，第二聲是出口的門關上。
Blood travels through three kinds of tubes. Arteries carry it away from the heart. Their walls are thick and stretchy, and the pulse you feel is an artery swelling with each squeeze. Arteries branch into capillaries, tubes so thin that blood cells must line up in single file to pass through. Their walls are only one cell thick, so oxygen and food can slip out and waste can slip in. Capillaries join into veins, which carry the blood back to the heart. For a long time, people in Europe believed that the body used up blood and kept making new blood. In 1628, the English doctor William Harvey showed that it must flow around and around in a circle.
血液在三種管子裡流動。動脈把血帶離心臟，管壁厚又有彈性，你摸到的脈搏，就是動脈隨著每一次擠壓鼓起來。動脈分支成微血管，細到血球必須排成一列才能通過；微血管壁只有一個細胞厚，氧氣和養分可以滲出去，廢物可以滲進來。微血管再匯集成靜脈，把血帶回心臟。很長一段時間，歐洲人以為身體會把血用掉、再不斷製造新的血；直到 1628 年，英國醫生威廉・哈維證明，血液一定是一圈又一圈地循環。
Your heart rate changes all day. It is slowest when you are asleep, and it speeds up when you run, get excited, or feel scared, so that more oxygen reaches your working muscles. For most adults, a resting pulse is between 60 and 100 beats a minute, and children's hearts usually beat a little faster. Regular exercise makes the heart muscle stronger, so it can pump more blood with each beat. Now find your own pulse, count it for 15 seconds, and let the heart in the model beat with yours.
心跳速度一整天都在變：睡覺時最慢；跑步、興奮或害怕時變快，好讓更多氧氣送到正在工作的肌肉。大多數成人安靜時的脈搏是每分鐘 60 到 100 下，孩子的心跳通常稍微快一點。規律運動讓心肌更強壯，每跳一下就能打出更多血。現在找到自己的脈搏，數 15 秒，讓模型裡的心臟跟著你的心跳一起跳。
Read aloud · 課文朗讀
Questions · 閱讀理解
Why do we say the heart is two pumps?
Because the right side and the left side each pump blood on their own path: the right side sends blood to the lungs, and the left side sends it to the rest of the body.
What happens to blood in the lungs, and what happens to it in the capillaries of the body?
In the lungs, blood drops off carbon dioxide and picks up oxygen. In the capillaries of the body, it gives oxygen and food to the cells and picks up waste.
What makes the lub-dub sound of the heart?
The valves snapping shut: first the valves between the atria and the ventricles, then the valves at the exits of the ventricles.
Words & Phrases · 生字及片語
heart(n.)心臟Your heart beats faster when you run up the stairs.跑上樓梯時，你的心臟跳得比較快。pump(v.)（用幫浦）打送Firefighters pump water from the river to put out the fire.消防員從河裡抽水來滅火。oxygen(n.)氧氣Fish take oxygen from the water with their gills.魚用鰓從水中取得氧氣。artery(n.)動脈The nurse felt the artery in my wrist to count my pulse.護理師摸我手腕的動脈來數脈搏。vein(n.)靜脈You can see the blue lines of veins under the skin of your hand.你可以看到手背皮膚下青藍色的靜脈。capillary(n.)微血管A capillary is thinner than a single hair.一條微血管比一根頭髮還細。pulse(n.)脈搏After the race, my pulse was 150 beats a minute.賽跑完，我的脈搏是每分鐘 150 下。valve(n.)瓣膜；閥門Turn the valve to stop the water.轉動閥門把水關掉。
Quick Check · 小測驗
1. Where does the right side of the heart send blood?
2. Which vessels carry blood away from the heart?
3. What do the valves in the heart do?
4. About how much blood does an adult have?
5. According to the reading, what did William Harvey show in 1628?
Four Chambers · 四個腔室
Two pumps, four rooms 兩個幫浦、四個房間
Atria on top collect; ventricles below pump. The right side handles oxygen-poor blood, the left side oxygen-rich blood, and the two never mix.
上面的心房負責收集，下面的心室負責打出。右邊處理缺氧的血、左邊處理充氧的血，兩邊從不混在一起。
Right ventricle右心室
A gentle pump: the lungs are close by, so it does not need to push very hard.
溫和的幫浦：肺就在旁邊，不需要太用力。
Left atrium左心房
Collects bright red, oxygen-rich blood fresh from the lungs.
收集剛從肺回來、充滿氧氣的鮮紅色血液。
Left ventricle左心室
The strongest chamber, with the thickest wall. Its squeeze is the pulse you feel.
最強壯、心壁最厚的腔室；你摸到的脈搏，就是它擠出來的。
Three Kinds of Tubes · 三種血管
Arteries, capillaries, and veins 動脈、微血管、靜脈
Laid end to end, all the blood vessels in an adult would stretch for tens of thousands of kilometers, and almost all of that length is capillaries.
把成人全身的血管接成一條，長度有好幾萬公里，而其中幾乎全是微血管。
Arteries動脈
They swell with every heartbeat. That swelling is the pulse you feel in your wrist and neck.
每次心跳都會鼓起來，那就是你在手腕、脖子摸到的脈搏。
Capillaries微血管
So narrow that blood cells pass in single file. This is where oxygen, food, and waste trade places.
窄到血球只能排成一列通過；氧氣、養分和廢物就在這裡交換。
Veins靜脈
Blood here moves slowly and gently. Little valves stop it from sliding back down your legs.
這裡的血流得又慢又輕；小小的瓣膜防止血從腿往下倒流。
Measure Yourself · 親身測量
Find your pulse and give the heart your beat 找到脈搏，讓心臟用你的速度跳
Use two fingers, not your thumb, because your thumb has a pulse of its own. Then press Measure my pulse and tap once for every beat for 15 seconds.
用兩根手指，不要用拇指，因為拇指自己也有脈搏。然後按「量我的脈搏」，15 秒內每摸到一下就按一次。
- 1Find it · 找到它Put two fingers on the thumb side of your wrist, just below the palm, and press gently until you feel a beat.兩根手指放在手腕靠拇指的一側、手掌下方一點，輕輕按到感覺有跳動。
- 15Count · 數一數Count the beats for 15 seconds, then multiply by 4 to get beats per minute. The model does the math for you.數 15 秒內跳幾下，再乘以 4 就是每分鐘的心跳。模型會幫你算。
- 30Move and measure again · 動一動再量Do 30 jumping jacks, then measure again right away. How much faster is it? How long until it slows down?做 30 下開合跳，馬上再量一次。快了多少？多久才慢下來？
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 lots of oxygen, dark red with less. Veins only look blue through your skin because of the way skin scatters light.血永遠是紅色的：含氧多是鮮紅、含氧少是暗紅。靜脈隔著皮膚看起來是藍的，是皮膚散射光線造成的。
✗ Myth · 迷思Your heart is on the left side of your chest.心臟在胸口的左邊。
✓ Fact · 事實It sits almost in the middle, behind the breastbone. Its tip points to the left, and the strong left ventricle is there, so the beat is easiest to feel on the left.它幾乎在正中間、胸骨後面，只是心尖朝左，強壯的左心室又在那一側，所以左邊最容易摸到心跳。
✗ Myth · 迷思Arteries carry oxygen-rich blood, and veins carry oxygen-poor blood.動脈裡是充氧血，靜脈裡是缺氧血。
✓ Fact · 事實Arteries and veins are named for their direction, not their oxygen. The pulmonary artery carries oxygen-poor blood to the lungs, and the pulmonary veins carry oxygen-rich blood back.動脈、靜脈是依方向命名，不是依含氧量。肺動脈把缺氧的血送到肺，肺靜脈再把充氧的血帶回來。
✗ Myth · 迷思The heart pumps blood to the lungs first, and then to the body.心臟先把血送到肺，再送到全身。
✓ Fact · 事實Both sides squeeze at the same moment. With every beat, the right side pushes blood toward the lungs while the left side pushes blood toward the body.左右兩邊在同一瞬間收縮。每跳一下，右邊把血推向肺的同時，左邊也把血推向全身。
Remember It · 記憶口訣
The heart in a sentence 一句話記住心臟
A for Artery, A for AwayArtery 的 A＝Away（離開）
Arteries carry blood away from the heart. Veins bring it back.
動脈把血帶離心臟，靜脈把血帶回來。
Right to breathe, left to feed右邊送去呼吸，左邊送去餵飽全身
The right side sends blood to the lungs to breathe in oxygen. The left side sends it out to feed every cell.
右心把血送到肺裡「呼吸」拿氧氣；左心把血送出去「餵」每一個細胞。
Lub-dub is two doors closing噗通＝兩道門關上
Lub: the doors between the upper and lower chambers shut. Dub: the doors at the exits shut. Turn on the sound in the model and watch the valves.
噗：上下腔室之間的門關上；通：出口的門關上。在模型裡打開心跳聲，對照瓣膜看看。
Your fist is your heart拳頭就是你的心臟
Make a fist: your heart is about that size, and it grows as you grow. Squeeze your fist hard: your heart does that about 100,000 times a day.
握個拳頭：你的心臟大約就這麼大，而且跟著你一起長大。用力握緊拳頭——你的心臟一天要這樣擠大約十萬次。
In Chinese · 中文怎麼說
Taking the Pulse, and a Ring with No End 把脈，與「如環無端」
In Chinese, taking someone's pulse is 把脈 (bǎmài), and in traditional Chinese medicine a doctor feels the pulse at three spots on the wrist. The ancient medical classic, the Yellow Emperor's Inner Classic (黃帝內經), describes the body's flow as moving “like a ring with no end” (如環無端). And Chinese often uses 心 (heart) for the mind as well: 心想 means to think, and 心跳 is simply a heartbeat.
中文把量脈搏叫「把脈」，中醫會在手腕上的三個位置切脈。古老的醫書《黃帝內經》形容身體裡的運行「如環無端」，像一個沒有終點的環。中文也常用「心」來指心思：「心想」是想，「心跳」就是心臟的跳動。
Classroom Activity 1 · 課堂活動一
Rest, Exercise, Recover: A Pulse Graph 安靜、運動、恢復：畫出脈搏圖
You need · 準備材料
- A clock or timer with seconds有秒針的時鐘或計時器
- A worksheet or graph paper學習單或方格紙
- Space to jump safely可以安全跳動的空間
Steps · 步驟
- Sit quietly for two minutes, then count your pulse for 15 seconds and multiply by 4.安靜坐兩分鐘，數 15 秒脈搏，再乘以 4。
- Do 30 jumping jacks and measure again right away.做 30 下開合跳，馬上再量一次。
- Measure again after 1, 2, and 3 minutes of rest.休息 1、2、3 分鐘後各再量一次。
- Graph your results: time along the bottom, beats per minute up the side. How long does your heart take to recover?把結果畫成圖：橫軸是時間、縱軸是每分鐘心跳。你的心臟要多久才恢復？
Teaching tip: compare graphs without ranking students. A heart that slows down quickly after exercise is a sign of fitness, and every student's graph will look a little different. Anyone with a heart condition can do the counting without the jumping.
教學提示：比較圖形，但不要替學生排名。運動後心跳很快就慢下來，是體能好的表現，而每個人的圖都會有點不一樣。有心臟疾病的學生可以只負責數，不用跳。
Classroom Activity 2 · 課堂活動二
A Paper-Tube Stethoscope 紙筒聽診器
You need · 準備材料
- An empty paper towel tube, or a sheet of paper rolled into a tube一個空的廚房紙巾捲筒，或一張捲成筒狀的紙
- A quiet room一間安靜的教室
- A partner一位同伴
Steps · 步驟
- Place one end of the tube on your partner's chest, a little left of the middle, and your ear on the other end.把紙筒一端放在同伴胸口正中偏左一點，另一端貼著你的耳朵。
- Listen for lub-dub. Count the beats for 15 seconds.聽「噗通」聲，數 15 秒跳幾下。
- Have your partner do 20 jumping jacks, then listen again. What changed?請同伴做 20 下開合跳，再聽一次。有什麼改變？
- Switch roles.交換角色。
Teaching tip: always ask before touching, and let students listen to their own heart if they prefer. The first sound is longer and lower; the second is shorter and sharper. Match them to the valves in the 3D model in slow motion.
教學提示：碰觸別人之前一定要先徵得同意，也可以讓學生聽自己的心跳。第一聲比較長、比較低，第二聲比較短、比較清脆；用 3D 模型的慢動作對照瓣膜看看。
⚕ Health note · 健康提醒This lesson is for learning about the body. It is not medical advice. If your heart races for no reason, or you feel chest pain or faint, stop and tell an adult right away. When feeling a pulse in the neck, press gently and on one side only.本課是認識身體的教材，不是醫療建議。如果心跳無緣無故變得很快，或覺得胸痛、快要昏倒，請馬上停下來告訴大人。在脖子量脈搏時要輕輕按，而且只按一邊。