雙語字幕
Human Circulatory System
人體循環(huán)系統(tǒng)
You can feel your heart fighting away every time you put your hand to your chest. But do you have any idea what's really going on in there, or what keeps your heart ticking as it should?
每次將手放在胸部，我們會感覺到心臟在跳動。但是，大家是否曾思考心臟跳動的機(jī)制是什么？哪些物質(zhì)保持心臟跳動？
Every day, your heart beats about 100,000 times sending 2,000 gallons of blood surging through your body. Although it's no bigger than your fist, your heart has the mighty job of keeping the blood flowing through 60,000 miles of blood vessels that feed your organs and tissues.
心臟每天跳動100,000次，向全身輸送2,000加侖的血液。雖然不足拳頭大小，但是它是保持血液通過約60,000m長的血管，供給器官和組織的重要器官。
Food, water and oxygen are essential for the existence of human life. Blood transports all these substances through various channels called blood vessels. Blood vessels involves arteries, veins, capillaries to keep the blood flowing throughout our body.
食物，水和氧氣是維持人類生命的關(guān)鍵物質(zhì)。通過血液運(yùn)輸所有這些物質(zhì)的不同管道稱為血管，包括動脈、靜脈和毛細(xì)血管，它們保持血液在全身流動。
We have a pumping system, and the heart is the pump, which is composed of muscle that pumps blood throughout the body beating approximately 72 times per minute of our lives. The human heart has four chambers, the right atrium, the left atrium, the right ventricle and the left ventricle. There are four valves in the heart. These valves are tricuspid valve, mitral valve, aortic valve, pulmonic valve. These valves are one-way valves.
人體內(nèi)存在泵血系統(tǒng)，心臟是泵，由肌肉組成，每分鐘跳動約72次，將血液泵送至全身，維持生命存活。心臟有四個腔室，即右心房、左心房、右心室和左心室。心臟有四個瓣膜，三尖瓣、二尖瓣、主動脈瓣和肺動脈瓣。這些瓣膜均是單向閥門。
Now, you have seen the structure of the heart, let us find out how it works. The blood becomes oxygen-rich by absorbing oxygen in the lungs. The function of the heart starts when oxygenated blood is carried from the lungs to the left atrium of the heart by means of the pulmonary veins. The left atrium relaxes, this blood is pumped into the heart. When the left atrium contracts, the left ventricle relaxes simultaneously.
現(xiàn)在，我們已經(jīng)知道了心臟的結(jié)構(gòu)，下面講解一下它的工作機(jī)制。血液吸收肺內(nèi)的氧氣，形成富氧血液。含氧血液通過肺靜脈自肺部流入心臟左心房時，心臟功能啟動。左心房松弛，血液被泵入心臟。左心房收縮，同時左心室松弛。
The left atrium pushes the blood into the left ventricle through the one-way valve. When the left ventricle contracts, the blood is pumped into the aorta which carries oxygenated blood to the different parts of the body except the lungs. Oxygenated blood reaches the different parts of the body through the blood vessels called the arteries. The arteries gets branched into capillaries which then reaches to the different organs of the body.
左心房推動血液通過單向瓣膜流入左心室。左心室收縮時，血液被泵入主動脈，主動脈將含氧血液輸送至除肺之外的其他不同身體部位。含氧血液到達(dá)身體不同部位所通過的血管稱為動脈。動脈分支為毛細(xì)血管，然后將血液輸送至身體不同的器官。
The blood then becomes deoxygenated and the blood capillaries gets mixed and form thicker blood vessels called the veins. The veins carry deoxygenated blood to the heart. The blood vessels that carry deoxygenated blood heart are known as the vena cava. The deoxygenated blood from different parts of body enters the upper right chamber of the heart which is called the right atrium. The right atrium get contracted allowing the blood to flow into the right ventricle which contracts with the expansion of The right atrium through the one-way valve. The right ventricle then contracts pushing the blood into the pulmonary artery.
然后，血液脫氧，毛細(xì)血管匯集，形成較粗的血管，即靜脈。靜脈將脫氧血液輸送入心臟。攜帶脫氧血液的血管稱為腔靜脈。來自身體不同部位的脫氧血液流入心臟右上腔室，即右心房。右心房收縮，使血液通過單向瓣膜流入右心室，右心室收縮伴右心房擴(kuò)張。然后右心室收縮，血液被推入肺動脈。
The pulmonary artery carries the deoxygenated blood to the lungs for oxygenation. The lungs oxygenate the blood by exchanging of gases and flows back into the heart through the pulmonary vein, and starts the circulatory cycle all over again.
肺動脈將脫氧血液攜帶入肺，進(jìn)行氧化。肺通過氣體交換使血液氧化，經(jīng)由肺靜脈，使血液流回心臟，并再次開始循環(huán)。
血液循環(huán)圖
