The pressure exerted by the flow of blood on the elastic walls of the arteries is called blood pressure. The blood pressure is greater during the systole than during the diastole. The blood pressure is measured by the use of sphygmomanometer. In normal young person the systolic pressure is 120mmHg and diastolic pressure is 80mmHg. Stethoscope was invented by William Stockers (1804−1878).