Circulatory systems
Introduced| English | Meaning |
|---|---|
| circulatory system/ˌsɜːkjʊˈleɪtəri ˈsɪstəm/ | The heart, blood and blood vessels that transport substances around the body. |
| double circulation/ˈdʌbl ˌsɜːkjʊˈleɪʃn/ | A system in which blood passes through the heart twice in a complete journey through the lungs and body. |
| pulmonary/ˈpʌlmənəri/ | pulmonary |
| systemic/sɪˈstemɪk/ | systemic |
The body's delivery network
- Your cells need a constant supply of oxygen and food, and a way to remove waste.
- The circulatory system 循环系统 — heart, blood and vessels — delivers it all.
In a double circulation, blood passes through the heart:
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Double circulation means two passes through the heart.
A double circulation 双循环
- Humans have a double circulation: blood passes through the heart twice per full circuit.
- One loop goes to the lungs (to pick up oxygen); the other goes to the body.
In a double circulation the blood passes through the heart twice on each trip round the body
Double circulation
Mammals have a double circulation — blood passes through the heart TWICE on each full trip round the body.
The pulmonary circulation carries blood between the heart and the:
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Pulmonary = to the lungs for oxygen.
The circulation that carries blood to the body (not the lungs) is the ______ circulation.
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Systemic = to the body; pulmonary = to the lungs.
The two loops
- Pulmonary 肺的 circulation: heart → lungs → heart (gets oxygen).
- Systemic 体循环的 circulation: heart → body → heart (delivers oxygen).
A benefit of double circulation is that blood reaching the body is:
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Re-pressurising the blood speeds delivery.
Fish have a single circulation, while mammals have a double circulation.
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Mammals pump blood twice per circuit.
Why double is better
- A double circulation lets blood be re-pressurised before going to the body.
- This delivers oxygen faster — important for active animals like mammals.
Fish have a single circulation; mammals have a double one. In a double circulation blood is pumped twice, keeping pressure high to the body. This supports a faster, more active lifestyle.
You've got it
- the circulatory system delivers oxygen/food and removes waste
- humans have a double circulation (blood through the heart twice per circuit)
- pulmonary loop = lungs; systemic loop = body; double = higher pressure, faster delivery