Integração dos sistemas corporais
International Baccalaureate · IB Diploma · Biology · SL Tópico 20 3:58 Narração em inglês · Legendas em inglês + 中文 gravadas
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Transcrição
Blood glucose rises after a meal, but usually does not keep rising indefinitely.
餐后血糖升高，但通常不会无限持续上升。
A control system responds to the change in internal conditions.
控制系统会对内部环境的变化作出反应。
Homeostasis maintains internal conditions within suitable limits.
稳态将内部条件维持在适宜范围内。
Receptors detect changes, coordination centres process information, and effectors respond.
感受器检测变化，协调中枢处理信息，效应器作出反应。
Negative feedback opposes the original change.
负反馈与原始变化相反。
Homeostasis is the maintenance of suitable internal conditions.
稳态即维持适宜的内部条件。
Negative feedback is a response opposing the original change.
负反馈即一种与原始变化相反的响应。
When blood glucose is high, insulin helps increase glucose uptake and storage as glycogen.
当血糖浓度较高时，胰岛素有助于增加葡萄糖的摄取和以糖原形式储存。
When it is low, glucagon supports release of glucose from stores.
当血糖浓度较低时，胰高血糖素支持从储存中释放葡萄糖。
These responses are coordinated, not identical effects of two hormones.
这些反应是协调一致的，而非两种激素产生的相同效应。
In the lab: Interpret a time graph by identifying the initial disturbance, the response and the return toward the normal range.
在实验室中，解读时间图时请识别初始扰动、反应以及向正常范围的回归。
Mark the delay before a response.
标记出反应出现前的延迟。
Do not assume a graph shows an instantaneous correction.
不要假设图表显示的是即时纠正。
Known: glucose changes from 5.0 to 7.0 arbitrary concentration units.
已知：葡萄糖浓度从 5.0 变为 7.0 任意浓度单位。
Increase equals final minus initial.
增量等于终值减去初值。
Increase equals 7.0 minus 5.0, which is 2.0 units.
增量等于 7.0 减 5.0，即 2.0 个单位。
Percentage increase equals 2.0 divided by 5.0, times 100, which is 40 percent.
百分比增量等于 2.0 除以 5.0，乘以 100，即 40%。
The numerical change is evidence of a disturbance, not a diagnosis on its own.
数值变化是干扰的证据，但本身并非诊断依据。
Your turn: A value rises from 4.0 to 5.0.
轮到你了：一个数值从 4.0 上升到 5.0。
Calculate the percentage increase.
请计算百分比增幅。
Pause the video and work it out.
请暂停视频，自己算一算。
Check: 1.0 divided by 4.0 is an increase of 25 percent.
核对：(5.0 − 4.0) ÷ 4.0，增加 25%。
Negative feedback does not mean the response is harmful or the measured value becomes negative.
负反馈并不意味着反应有害或测量值变为负数。
Diabetes has different mechanisms; do not treat every case as a failure to make insulin.
糖尿病的机制各不相同，不要将每种情况都视为胰岛素分泌失败。
Not true: Negative feedback always makes the measured value negative.
不正确。 负反馈并不总是使测量值变为负数。
Negative feedback means the response opposes the change - it pushes the value back towards the set point.
负反馈是指反应抵消变化，将数值推回设定点。
"Negative" describes the direction of correction, not a harmful effect or a negative measurement.
“负”描述的是纠正的方向，而非有害影响或负向测量值。
Homeostasis maintains internal conditions within suitable limits.
稳态将内部条件维持在适宜范围内。
When blood glucose is high, insulin helps increase glucose uptake and storage as glycogen.
当血糖升高时，胰岛素有助于增加葡萄糖的摄取和以糖原形式储存。
Watch for: negative feedback does not mean the response is harmful or the measured value becomes negative.
请注意：负反馈并不意味着反应有害或测量值变为负数。
A value rises from 5.0 to 6.5.
一个数值从 5.0 上升到 6.5。
Find the percentage increase.
请计算百分比增幅。
Negative feedback opposes the change. It does not make the value negative.
负反馈会抵消这种变化，但并不会使该数值变为负数。
The result is a rise of 30 percent.
结果是上升30%。
When blood glucose rises, insulin makes cells take up glucose and store it as glycogen.
血糖升高时，胰岛素使细胞吸收葡萄糖并储存为糖原。
When it falls, glucagon makes the liver release glucose.
血糖下降时，胰高血糖素使肝脏释放葡萄糖。
Each response reverses the change: negative feedback.
每种反应都逆转原来的变化：这就是负反馈。
A fictional regulated variable changes from 4 to 5 units, then returns to 4.
一个虚构的调节变量从 4 变为 5 个单位，随后又回到 4。
Explain the sign of the corrective response and why recovery alone does not identify the sensor.
请解释校正反应的方向，并说明为何仅凭恢复过程无法确定传感器。
The disturbance is plus 25 percent.
扰动是增加 25%。
A negative-feedback response opposes it.
负反馈反应会抵消这一变化。
Recovery is consistent with regulation but cannot by itself identify the sensor or the signalling pathway, or rule out another cause.
恢复与调节相符，但仅凭恢复本身无法确定感受器或信号通路，也无法排除其他原因。
Pause and check yourself. Explain each point on screen in your own words, then change one number in the last example and say which assumption must still hold.
暂停一下，自我检查：用自己的话解释屏幕上的每个要点，再改动最后一个例子中的一个数字，说明哪个假设仍然必须成立。