Senior – B.P Apparatus Mercury – NSL

数字B.P设备最常通过sphygmomanometer从历史上看，这使用汞柱的高度反映了循环压力。^[1]血压值通常在汞的毫米（MMHG），尽管不包含Aneroid和电子设备mercury。

对于每个心跳，血压在收缩压和舒张压之间变化。收缩压是动脉中的峰值压力，发生在附近心脏周期当。。。的时候心室收缩。舒张压是最低前ssure in the arteries, which occurs near the beginning of the cardiac cycle when the ventricles are filled with blood. An example of normal measured values for a resting, healthy adult human is 120 mmHg收缩期和80 mmHg舒张期（写为120/80 mmhg，并以“八十多岁的二十多岁”而讲）。

Systolic and diastolic arterial blood pressures are not static but undergo natural variations from one heartbeat to another and throughout the day (in a昼夜节律rhythm). They also change in response tostress，营养因素，drugs，，，，disease, exercise, and暂时站起来。有时变化很大。高血压refers to arterial pressure being abnormally high, as opposed to低血压，当它异常低。随着体温，，，，呼吸频率，，，，and心率，血压是医疗专业人员和医疗保健提供者通常监测的四个主要生命体征之一。^[2]

Measuring pressure侵入性，，，，by penetrating the arterial wall to take the measurement, is much less common and usually restricted to a hospital setting.